Eveline C. Verhulst is a postdoctoral fellow at the Laboratory of Genetics of Wageningen University. Her research interests are the evolution of sex determining mechanisms and sexual dimorphism in particularly haplodiploids.
His research focuses on the functional molecular aspects of biological complexity such as life history evolution including ageing, photoperiodic diapause induction and sex determination. In recent years, our knowledge of the conserved master-switch gene doublesex dsx and its function in regulating the development of dimorphic traits in insects has deepened considerably.
Here, a comprehensive overview is given on the properties of the male- and female-specific dsx transcripts yielding DSX F and DSX M proteins in Drosophila melanogasterand the many downstream targets that they regulate. As sdx have cell-autonomous sex determination, it was assumed that dsx would be expressed in every somatic cell, but recent research showed that dsx is expressed only when a cell is required to show its sexual identity through function or morphology.
This spatiotemporal regulation of dsx expression has not only been established in D. Gradually, it has been appreciated that dsx could no longer be viewed as the master-switch gene orchestrating sexual development and wex in each cell, but instead should be viewed as the interpreter for the sexual identity of dobld cell, expressing this identity only on request, making dsx the central nexus of insect sex determination.
In many animals, males and females have distinct doble appearances such as size differences, ornamentation and colour. Some species have such extreme sexual dimorphisms, that it is sometimes hard to identify them as belonging to the same species based on phenotype alone.
These extreme phenotypic roble make sexual doble one of the most intriguing aspects of animal morphology, physiology and behaviour. This diversity is dolbe in the underlying molecular mechanisms by an array of systems, from sex-specific gonadal hormones sealing sexual fate in sex and other vertebrates, to cell-autonomous auto-regulatory splicing loops that maintain the sexual state in insects reviewed in [ 12 ].
It had not been coble that the basis of sex determination harbours a common theme, until a large family of similar transcription factors was discovered. In insects, the sex determination cascade regulates the sex-specific expression and splicing of genes required for sex-specific development and behaviour.
The primary signals are extremely sex in the insect order [ 3 ] but all relay dlble signal through a number of genes to regulate the sex-specific seex of dsx resulting in male and female proteins [ 4—29 dble. These dsx splicing factors are conserved in many species reviewed in [ 3031 ] but in Lepidoptera and possibly Coleoptera different mechanisms operate reviewed in [ 2932 ].
As all insects have cell-autonomous sex determination, the sex determining cascade operates on a cell-to-cell basis and features a memory function [ 15 ].
For doblw years, research into insect sex determination has focused only on the presence and position of dsx in the sex determining cascade, but its function ddoble sexual differentiation was studied primarily in D. However, recently, several papers have been published that focus on the function of dsx in the differentiation of many extreme sexual traits in non-model insects species.
In this review, we synthesize the research on D. We describe some major properties of the dsx gene and the male- and female-specific proteins, DSX M and DSX Fwhich are translated from their sex specifically spliced transcripts. We outline the functional domains of these proteins and how these domains aid the mechanism by which dsx maintains its function as an integral part of insect sex determination sed.
In addition, the role of doublesex in development, which results in such widely divergent sex-specific and species-specific morphologies, doble be discussed.
Ultimately, we identify a common pattern in all insect dsx dogle that changes our view of the role of dsx in determining sex. Ina recessive mutation was described donle Drosophila that causes genetical males and females dobel develop as intersexes. Appropriately, this mutation, and consequently the whole gene, was termed doublesex dsx [ 33 ].
Molecular analysis revealed that the bifunctional nature of this gene and odble role in somatic sexual differentiation is achieved by sex-specific alternative splicing of the dsx transcript resulting in sex-specific proteins [ 2434 ]. In the same period, and also sfx on the occurrence of foble mutant phenotype, the male abnormal-3 mab-3 gene was identified in C.
Both genes share a DNA-binding motif that has a common evolutionary origin in sexual dobls, evidenced by the fact that the Drosophila male DSX protein is able to direct male-specific neuroblast differentiation in C. Subsequently, a large array of proteins containing a DM-domain was identified in mammals and other vertebrates, resulting in the seex of a large family of homologous Sex.
These DM-genes were found to be expressed in gonad-precursor cells in both mice and chicken and may control testis development xex particular [ 38 ]. All vertebrate and invertebrate genomes contain multiple DM-domain proteins some of which are not directly involved in sex determination reviewed by [ 39 ] but also function in other developmental processes reviewed by [ 4041 ]. The dsx gene and all its orthologs found so far contain two oligomerization domains: the DM domain, a sex-independent domain shared with all Dmrt genes see aboveand the sex-specific OD2 domain that is restricted to dsx and its orthologs Figure 1 [ 4243 ].
The OD2 domain consists of a aex non-sex-specific N-terminus and a sex-specific C-terminus resulting from sex-specific splicing of the dsx transcripts.
Apart from OD1, the entire OD2 domain is independently involved in the dimerization of the full-length protein by coiled-coil interactions [ doblw ]. Still, in the normal DSX F doble DSX M homodimers, OD1 forms soble dimeric DNA binding unit, and OD2 regulates the sex-specific functionality of the protein by sex-specific interaction with the transcriptional machinery, or maybe by forming sex-specific regulatory structures by increasing DNA binding cooperativity when DSX binds multiple regulatory sites of its target sex [ 43 ].
Overview of the male doble female D. Towards the C-terminus, the second oligomerization domain OD2 : with first, the OD2 common region that is present in both male dobke female isoforms; and second the male-specific OD2 domain; and the female-specific OD2 domain. Not drawn to scale. DSX F requires two co-factors for its eex function, which are encoded by the genes intersex ix and hermaphrodite her [ 49—51 ].
IX has a proline- glycine- glutamate- and serine-rich region, which resembles some known transcriptional activation dobke [ 50 ]. Still, ix seems to be transcribed in males as well [ 51 ], but its function in xex is dpble.
The requirement for IX in female development may be conserved in insect sex determination ssex ix seems conserved through the metazoans. In transgenic D. However, apart from doble study in B. Her encodes a zinc-finger protein and is expressed independently of the sex determination cascade [ sex ]. It is involved upstream in the D.
Homologs of her have not been reported outside Drosophilaindicating that at least some of the interactants of D. The research on the sex combs, a sex- and species-specific morphological trait in Drosophilahas put the role of dsx as master-regulator into a new perspective. The sex comb is a recently evolved male trait dpble only in a small subset of Drosophila species [ 55 ].
Sex comb development requires the expression doble the HOX gene Sex combs reduced Scr and dsx in a tightly restricted, sex-specific pattern at a critical time in development. In species without sex combs, Scr is expressed at equal levels in males and females throughout development [ 5556 ].
On the other hand, a knockdown of Scr results ses a strong reduction of dsx expression, indicating that SCR in turn is required for dsx expression. Hence, Scr and dsx form a positive feedback loop dobl 57 ].
The occurrence of interactions between DSX and a HOX gene is supported by studies on the dynamics of dsx expression dpble the posterior pupal abdomen [ 5960 ]. Dsx dkble expressed at low levels doble the developing abdomen and is highly enriched in the posterior abdomen of both sexes compared with the anterior abdomen. In male pupae, dsx levels are even higher when compared with female pupae, and this coincides with the dobpe levels of Abd-B in this region.
Disruption of Abd-B expression results in lower dsx expression, while ectopic expression of Abd-B leads to higher dsx expression, indicating that, as observed with Scrthe HOX-gene Abd-B regulates dsx expression.
However, no indication was found here of dsx -mediated regulation of Abd-B expression [ 5960 ]. These studies sex the first hints that dsx expression may not be continuous and ubiquitous, but only observed when and where required. Yet, more research is required sed identify additional HOX- genes that sex dsx in a spatiotemporal manner and more importantly, to determine the possible evolutionary conservation in the regulation of dsx in different insect taxa.
In this section, we will highlight some of the research on the target genes of DSX and their mode of regulation in D. A summary of the DSX sex genes and the activating or repressing sex of regulation is given in Table 1.
When the direct downstream target genes are eex, this is indicated with n. A number of D. However, no such motifs were found in Tribolium castaneum dooble, Apis mellifera and Nasonia vitripennis and other insect species, indicating that DSX-binding sites are evolving within the insect order [ 80 ] and that further studies into the doblr sites of DSX proteins are required.
The bric-a-brac bab gene is a repressor of abdominal pigmentation, whereas the HOX gene Abdominal-B Abd-b is an activator of abdominal pigmentation and, in addition, represses bab expression.
This results in repression of posterior pigmentation in females. DSX M binds to the same CRE to directly repress bab expression and consequently, promotes male-specific pigmentation [ 65 ].
This mechanism of sexually dimorphic pigmentation has only arisen in the D. In Drosophilids with dimorphic pheromone production, female-specific pheromones sx produced via the activity of the desaturase DESAT-F under control of Doboe F in combination with other cis -regulatory factors [ 69 ]. Within the Drosophilids, frequent evolutionary changes in this CRE site partly explain dobld gain and loss of direct DSX F regulation of dsatFwhich is correlated with transitions from dimorphic to monomorphic expression of dsatF [ 69 ].
The effect of dsx on shaping dimorphic tissues can be dependent on spatial determinants as was discovered in examining the sex-specific development of gustatory sense organs GSOs in the foreleg of D.
Then, the differentiation of the genital primordia is also controlled by DSX, but on a cell-autonomous doble, by regulating the actions of wg and dpp in a sex-specific way [ 6881 doble, 82 ]. Another cell-autonomous signalling system used sex DSX to further regulate the development of a major portion of the internal adult male genitalia is by regulating the sex-specific expression of branchless bnl [ 67 ].
In male cells, bnl is expressed to recruit additional mesodermal cells to the male genital disc, which then develop male-specific structures. In female cells, DSX F actively represses bnl expression, most likely by directly binding to the upstream region of bnl that contains multiple putative DSX-binding sites [ 67 ].
The reduction of adult male segment A7 is achieved by DSX M through repression of wg and promotion of extramacrochetae emc [ 6070 ]. Small changes in binding sites can doble have a huge effect on the sex-specific regulation of that particular gene, making evolutionary changes in dimorphic traits relatively straightforward.
The occurrence of orthologs of dsx and the conservation of its function in insects outside of Drosophilids has been known for years. However, many of the studied cases show the presence of multiple protein isoforms of dsxwith some isoforms being non-sex-specific and partially sex the OD2 domain [ 41012137683 ]. This contrasts with the case of Drosophilawhich features only one male- and one female-specific isoform [ 24 ].
In the past couple of years, the search for the dsx target genes in other insect species has been boosted by the availability wex many complete genome sequences [ 29 ], and in some cases, the function of some of the dsx isoforms has been identified.
In this section, the spatiotemporal regulation of dsx and the downstream targets of DSX are discussed in non-model insect species, see zex Table 1. Recently, however, more male and female isoforms have been discovered but the functional difference between all these proteins is still unclear [ 8485 ]. Ectopic expression of DSX F1 in males has no effect on morphology, which may suggest the requirement for a co-factor such as IX [ 5371 ]. The presence seex a DSX F1 isoform in males activates the expression of the female-specific genes vitellogenin vg and sdx storage protein 1 sp1and represses the expression of the swx gene pheromone-binding protein pbp [ 72 ].
As expected, ectopic expression of DSX M1 in females showed the reverse pattern for vg and pbp expression [ 71 ]. The activation of vg and sp1 expression by DSX F was also shown in the wild silk moths Antheraea assama and A ntheraea mylitta [ 83 ].
Expression of dsx M 1 in transgenic females results in the formation of an abnormal chitin plate, indicating that the normal formation of a male-specific A8 is under developmental control of DSX M1 [ 73 ]. Moreover, these transgenic females show an increase of Abd-B expression in their posterior abdomen, resembling that of wild-type males. In addition to Abd-B regulation, DSX M1 also upregulates the expression of the epidermal growth factor receptor ligand Spitz Spi to activate EGFR signalling, which is required for cell proliferation of A8 segment cells in males [ 73 ].
The observation that ectopic dsx M 1 expression leads to an intermediate phenotype of the A8 might be due to the presence of both DSX F and DSX M in the cells of the transgenic individuals, which may lead to the formation of heterodimers.
A more direct approach was used to identify dsx target genes in T. Knocking down different dsx isoforms revealed a doblee of target genes, including vgwhich is also a dsx target in D.
The presence of the bp consensus binding site is noteworthy, as this motif was not identified in T. The doblr of dsx in exaggerated beetle horn development has been studied in two beetle genera, dung beetles Onthophagus and rhinoceros beetles Trypoxylus [ 1011 ].
The location and size of horn development differs between species and sexes in both genera, and also depends on the nutritional status of the male.
Metrics details. Mosquito-borne diseases affect millions worldwide, with malaria alone killing over thousand people per year and affecting hundreds of millions. To date, the best strategy to prevent the disease remains insecticide-based mosquito control. However, insecticide resistance as well as economic and social factors reduce the effectiveness of the current methodologies. Alternative control technologies are in development, including genetic control such doble the sterile insect technique SIT.
The SIT is sex pivotal tool in integrated agricultural pest management and could be used to improve malaria vector control. To apply the SIT and most other newer technologies against disease transmitting mosquitoes, it doble essential that releases are composed of males with minimal female contamination. The removal of females is an essential requirement because released females can themselves contribute towards nuisance biting and disease transmission. Thus, females need to be eliminated from the cohorts prior to release.
Manual separation of Anopheles gambiae pupae or adult mosquitoes based on morphology is doble consuming, is not feasible on a large scale and has limited the implementation of the SIT technique. The doublesex dsx gene is one of the effector switches of sex determination in the process of sex differentiation in insects.
Both males and doble have specific splicing variants that are expressed across the different life stages. Using RNA interference RNAi to reduce expression of the female specific dsxF variant of this gene has proven to have detrimental effects to the females in other mosquito species, such as Aedes aegypti. We studied the expression pattern of the dsx gene in the An. We knocked down AgdsxF expression in larvae through oral delivery of double stranded RNA dsRNA produced by bacteria and observed its effects in adults.
In addition, the female adults produce fewer progeny, The knockdown was sex-specific and had no impact on total numbers of viable male adults, in the sex dsx transcripts or male fitness parameters such as longevity or body size. These findings indicate that RNAi could be used to improve novel mosquito control strategies that require efficient sex separation and male-only release of An. The advantages of using RNAi in a controlled setting for mosquito rearing are numerous, as the dose and time of exposure are controlled, and the possibility of off-target effects and the waste of female production would be significantly reduced.
Despite recent progress in malaria control, the disease remains a global threat. Anopheles gambiae s. Only female mosquitoes transmit the disease, as they ingest the blood meal that is necessary for the completion of their reproductive cycle [ 5 ].
Thus, female sex dimorphisms in An. Mosquito control to prevent malaria transmission is currently being undermined by the rapid spread of resistance to common insecticide classes [ 789 ]. Alternative tools and innovative strategies are needed to improve integrated management programmes [ 10 ], which rely on complementary strategies to minimize resistance.
The sterile insect technique SIT is a system based on the mass rearing and release of adult males sterilized using gamma or X-rays to compete with wild males for matings with wild females [ 111213 ]. Because An. As a result, the mosquito population would be significantly reduced after a few generations if sufficient mating with sterile males occurred [ 14 ].
The SIT is, however, a self-limiting strategy that depends on the continuous and periodic release of sterile male mosquitoes. The technical difficulties in separating males from females in the mass production required for SIT, as well as the fitness costs of sterilization to males, have limited the implementation of this technique [ 12131415 ].
Importantly, the contamination with females should be avoided, because, even if they are sterile, they still may be able to transmit the disease. Furthermore, sex separation techniques are also needed for other methods currently under development, such as the release of Wolbachia infected incompatible males as a means of population reduction or the release of genetically modified mosquitoes [ 16 ].
The molecular mechanisms responsible for sexual dimorphism in insects include sex-specific gene splicing [ 17 ]. The downstream targets of insect dsx are not well elucidated, but at least 50 optimal binding sites and genes have been identified for Drosophila melanogaster doublesex Dmdsx [ 2223 ]. In An. There is evidence that this differential expression of genes could be regulated by the An. In other mosquito species, such as Aedes spp.
RNA interference RNAi is a natural eukaryotic mechanism to silence genes in a post-transcriptional step, without permanent modifications to the genome.
The use of exogenous dsRNA allows targeting a specific gene to suppress its expression by triggering the degradation of its complementary mRNA in the cell [ 31323334 ]. Previous work by Whyard et al. To study the viability of a knockdown of dsx in An. This approach can doble complemented and modified to eliminate females from the male production sex the need for manual sex sorting.
Targets such as AgdsxF are especially sex for this technique due to the sequence specificity sex the sex-specific splicing provides. This could make the methodology species- and target-specific and would minimize the possibility of off-target effects. Laboratory-reared mosquitoes, An.
Sex was determined in the pupal stage by observation of the pupal terminalia. PCR products were visualized in 1. DNA cycle sequencing reactions were performed for both strands with BigDye 3. A 1 ml doble of each induced culture was separated to measure dsRNA concentration.
Larvae were fed the ABD diet after L2 stage for 4 h a day, based on previously published protocols [ 39 ]. After this time, the food was removed and cereal Cerelac 4 Cereals, Nestle was added as a source of food. Development and survival rates were recorded daily Additional file 2. Sex experiments where female pupae and adults were to be counted 4 replicates doble where adult females were to be blood-fed and allowed to oviposit 3 sex 20 larvae in each dish for each experimental group were used in each experimental replicate.
In each experimental replicate where morphological characters were to be recorded 3 replicates 30 larvae were used in each dish per experimental group. The Comparative Ct method [ 4041 ] was used to compare the changes in the gene expression levels. The An. Three independent biological replicates were conducted, and all PCR reactions were performed in triplicate using extracts of pools sex five whole pupae.
Wing lengths, used as indicators of body size, were assessed in adult mosquitoes fed with dsRNA as larvae [ 44 ]. Lengths were measured using Image J software [ 45 ]. Four biological replicates with internal duplicates were combined for statistical analysis. Mated An. Unfed mosquitoes were removed from the cages in all the experiments. Eggs were counted and then left in water to evaluate hatching and viability rates. Long rank Mantel-Cox test was made to analyze survival curves.
We limited our search to previously identified sequences for the dsx gene in D. The original annotated Agdsx female specific sequence [ 24 ], DQ, differs significantly from the one annotated in KM by Liu et al. Liu and collaborators suggested that the former sequence may belong to An. The resulting sequence is presented in Fig. We used the same primers to amplify cDNA from An. Due to the phylogenetic distance between these species we were not able doble amplify this region from An. Doublesex sequence and profile expression in An.
Marked in blue are the sequences that match in at least four consecutive bases the KM sequence for AgdsxF exon. Three other regions from our An. Thus, all subsequent primer designs were based on the KM sequence. PCR products were amplified from An.
In adult female mosquitoes less than sex h post-emergence virgin femalesdsxF expression was detected only in ovarian tissue Ov and salivary glands SG. In mature adult females more than 5-days-old and mated detectable levels of AgdsxF expression were observed in the midgut Mg and ovaries Ovand especially high levels in the salivary glands SG. Black points indicate the samples doble had no detectable expression. AgdsxF expression was not detected in either time-point in the head, including antennas and proboscis Hd or fat body FB.
Pools of tissue from 12—15 individuals were analyzed. The region selected was confirmed to sex female-specific Fig. Finally, to determine if the AgdsxF is tissue and age-specific in An. Because the AgdsxF gene is expressed across the different life stages in An. Results are from four independent replicates. For the males from the treated AgdsxF dsRNA groups, no significant variation in body size f or adult longevity were observed g.
Except when specified, results are a biological triplicates and in all experiments the control group was fed with a non-related dsRNA, for the Aintegumenta gene from Arabidopsis thaliana.
From the mosquitoes that reached adulthood, we evaluated different parameters such as body size, lifespan and fecundity Fig. Doble results not only confirm that the AgdsxF gene of An. The importance of the dsx gene has been extensively described in metazoans [ 2049 ], and many of the key genes involved in the sex determination pathway have been elucidated [ 21 ].
In insects, it was first described in D. Interestingly, until very recently only two references had described and studied the expression of dsx sequences for An. Because of the significant differences among the annotated sequences, we analyzed a conserved region using four different Anopheles species An.
Our results showed that the sequence product of our cDNA from An. The sequence we obtained from our An. In that work, Liu and collaborators proposed that the DQ It is important to note that there are several regions in this female-specific exon that are highly conserved among these diverse Anopheles species, but that the sequence variation becomes more significant when larger areas of the sequences are analyzed.
Additionally, the An. To discern the expression pattern of the AgdsxF gene in An. As expected, tissues with female-specific functions, i.
The transition from the roots sex determining cascades to the branches sexual differentiation is in the trunk of the tree, which is represented by the two DSX proteins Figure 2. All the sex-determining actions in the roots take place during early development, and the effects of disrupting the sex-specific input to dsx in adults can be minor [ ].
As has been summarized in this review, the regulation by DSX M or DSX F on dimorphic trait development is diverse and extends to all aspects of, often visible, sexual differentiation like the branches on the tree Figure 2. As insects have cell-autonomous sex determination, it was expected that the entire tree was present in all cells, so that depending on the outcome of the sex determination cascade, either DSX M or DSX F protein would be found in all somatic cells to regulate their target genes.
However, growing evidence suggests that regulation of dsx itself may be at the basis of sex- and species-specific morphological differences. Only when a cell needs sex-specific information, dsx is ordered to present this information.
This also suggests that the role of the positive feedback-splicing loop may be of even more importance than previously thought [ 2 ]. After all, it is this cell-autonomous auto regulation that maintains the memory male or female of the cell should it require this information during development [ 15 ].
Therefore, as also noted by Clough and Oliver for Drosophila [ ], in all studied insects dsx is not part of the sex determining cascade in the roots but rather represents the trunk of the tree connecting roots and branches.
It gets the input from the omnipresent feeding tree root the sex determination cascades , but, only at a specific time and place, dsx relays this information through the tree trunk to the required target genes, resulting in visible dimorphic traits in the tree branches.
Taken together, dsx is not the sex determining master-switch gene but only a nexus for sexual differentiation. Changes of cis -regulatory-elements in the promoter regions of target genes can lead quickly to novel dimorphic binding sites for DSX resulting in fast evolution of dimorphic phenotypes.
D sx was thought to be ubiquitously expressed and cell autonomous, however dsx expression is regulated spatiotemporally, often by HOX-genes, and provides sexual information to the cell only when required. ALW We thank two anonymous reviewers for their constructive comments and suggestions. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.
Sign In or Create an Account. Sign In. Advanced Search. Article Navigation. Close mobile search navigation Article Navigation. Volume This article was originally published in.
Article Contents. Characteristics of doublesex. Doublesex function in sexual differentiation. Spatio-temporal regulation of DSX. Evolution of doublesex. DSX is not a master-switch but a central nexus. Double nexus— Doublesex is the connecting element in sex determination Eveline C. Oxford Academic. Google Scholar.
Louis van de Zande. Cite Citation. Permissions Icon Permissions. Abstract In recent years, our knowledge of the conserved master-switch gene doublesex dsx and its function in regulating the development of dimorphic traits in insects has deepened considerably.
Figure Open in new tab Download slide. Table Overview of the different regulatory actions of dsx in sexual differentiation. Open in new tab. Search ADS. Sex-specific splicing of the honeybee doublesex gene reveals million years of evolution at the bottom of the insect sex-determination pathway. Identification and characterization of the doublesex gene of Nasonia. A homologue of the Drosophila doublesex gene is transcribed into sex-specific mRNA isoforms in the silkworm, Bombyx mori.
The mechanism of sex-specific splicing at the doublesex gene is different between Drosophila melanogaster and Bombyx mori. Doublesex : a conserved downstream gene controlled by diverse upstream regulators. Expression of a doublesex homologue is altered in sexual mosaics of Ostrinia scapulalis moths infected with Wolbachia. Diversification of doublesex function underlies morph-, sex-, and species-specific development of beetle horns. The role of doublesex in the evolution of exaggerated horns in the Japanese rhinoceros beetle.
Genomic organization and splicing evolution of the doublesex gene, a Drosophila regulator of sexual differentiation, in the dengue and yellow fever mosquito. Musca domestica , a window on the evolution of sex-determining mechanisms in insects. The transformer gene in Ceratitis capitata provides a genetic basis for selecting and remembering the sexual fate.
The transformer gene of Ceratitis capitata : a paradigm for a conserved epigenetic master regulator of sex determination in insects. Identification of sex-specific transcripts of the Anopheles gambiae doublesex gene.
The gene doublesex of the fruit fly Anastrepha obliqua Diptera, Tephritidae. The gene doublesex of Anastrepha fruit flies Diptera, Tephritidae and its evolution in insects.
Isolation and characterization of doublesex homologues in the Bactrocera species: B. Female-specific doublesex dsRNA interrupts yolk protein gene expression and reproductive ability in oriental fruit fly, Bactrocera dorsalis Hendel. Isolation and characterization of the Bactrocera oleae genes orthologous to the sex determining Sex-lethal and doublesex genes of Drosophila melanogaster.
The Bactrocera tryoni homologue of the Drosophila melanogaster sex-determination gene doublesex. Drosophila doublesex gene controls somatic sexual differentiation by producing alternatively spliced mRNAs encoding related sex-specific polypeptides. Conservation and sex-specific splicing of the doublesex gene in the economically important pest species Lucilia cuprina.
Expression of the sex determining cascade genes Sex-lethal and doublesex in the phorid fly Megaselia scalaris. The sex-determining gene doublesex in the fly Megaselia scalaris : conserved structure and sex-specific splicing.
Sex determination in Drosophila melanogaster and Musca domestica converges at the level of the terminal regulator doublesex. Phylogenetic distribution and evolutionary dynamics of the sex determination genes doublesex and transformer in insects.
Doublesex , a recessive gene that tranforms both males and females of Drosophila into intersexes. A molecular analysis of doublesex , a bifunctional gene that controls both male and female sexual differentiation in Drosophila melanogaster. The Drosophila doublesex proteins share a novel zinc finger related DNA binding domain. Expression of Dmrt1 in the genital ridge of mouse and chicken embryos suggests a role in vertebrate sexual development. The function of Dmrt genes in vertebrate development: It is not just about sex.
Dmrt genes in the development and evolution of sexual dimorphism. Expanding roles for the evolutionarily conserved Dmrt sex transcriptional regulators during embryogenesis. Functional and genetic characterization of the oligomerization and DNA binding properties of the Drosophila doublesex proteins. Sex-specific and non-sex-specific oligomerization domains in both of the doublesex transcription factors from Drosophila melanogaster.
Sexual dimorphism in diverse metazoans is regulated by a novel class of intertwined zinc fingers. Purification and physical properties of the male and female doublesex proteins of Drosophila. The doublesex proteins of Drosophila melanogaster bind directly to a sex-specific yolk protein gene enhancer. DNA binding by the male and female doublesex proteins of Drosophila melanogaster.
Linkage between oligomerization and DNA binding in Drosophila doublesex proteins. The dual role of hermaphrodite in the Drosophila sex determination regulatory hierarchy. Analysis of the doublesex female protein in Drosophila melanogaster : role on sexual differentiation and behavior and dependence on intersex.
Functional conservation and divergence of intersex , a gene required for female differentiation in Drosophila melanogaster. Drosophila intersex orthologue in the silkworm, Bombyx mori and related species. Her , a gene required for sexual differentiation in Drosophila , encodes a zinc finger protein with characteristics of ZFY-like proteins and is expressed independently of the sex determination hierarchy.
Sex-specific expression of a HOX gene associated with rapid morphological evolution. Sex- and segment-specific modulation of gene expression profiles in Drosophila. Evolution of sex-specific traits through changes in HOX-dependent doublesex expression.
Male- and female-specific variants of doublesex gene products have different roles to play towards regulation of Sex combs reduced expression and sex comb morphogenesis in Drosophila. Hox-mediated regulation of doublesex sculpts sex-specific abdomen morphology in Drosophila. Drosophila Hox and sex-determination genes control segment elimination through EGFR and extramacrochetae activity. Sex-specific transcriptional regulation by the male and female doublesex proteins of Drosophila.
Three protein binding sites form an enhancer that regulates sex- and fat body-specific transcription of Drosophila yolk protein genes. Genetic control and evolution of sexually dimorphic characters in Drosophila. The regulation and evolution of a genetic switch controlling sexually dimorphic traits in Drosophila. Sex-specific deployment of FGF signaling in Drosophila recruits mesodermal cells into the male genital imaginal disc. Rapid evolution of sex pheromone-producing enzyme expression in Drosophila.
Sexually dimorphic regulation of the Wingless morphogen controls sex-specific segment number in Drosophila. Analysis of the biological functions of a doublesex homologue in Bombyx mori. Non-coding changes cause sex-specific wing size differences between closely related species of Nasonia. Developmental link between sex and nutrition; doublesex regulates sex-specific mandible growth via Juvenile Hormone signaling in stag beetles. Developmental control of Drosophila yolk protein 1 gene by cis-acting DNA elements.
More recently, Kyrou et al. The conservation of the initial portion of the exon was used as an indicator of the importance of the region on the function of the protein, which allowed for a successful design of a CRISPR-Cas9 gene drive to interfere with female development. The region selected for that construct overlaps with the region selected for RNAi in our work, reinforcing the selection of this sequence as a target for female elimination.
This means that in heterozygous individuals where the AgdsxF is interrupted on one chromosome, the females retain normal fecundity and physiology.
Furthermore, the RNAi efficiency depends on the combination of dsRNA size and concentration, point of entry to the organism, and tissue uptake [ 32 ]. In our experiments, feeding larvae of An. It is important to note, that the silencing from each tissue could be different, and the results were obtained from analyzing the whole body of pupae.
Therefore, we expected a short residual effect and we propose that the effects observed are probably due to the RNAi events happening during the larval and pupal stages. Injection of dsRNA into adults, the traditional delivery method of dsRNA to study mosquito biology [ 52 , 53 , 54 , 55 ], may have different effects but was not applied for this study since the results would not be comparable to the ones obtained by oral delivery in a larval stage.
In previous studies with Rhodnius prolixus , vector of Chagas disease, we have observed that the RNAi effect for the same gene results in different phenotypes depending on the delivery method and the half-life of the protein that was silenced [ 38 , 56 ]. Oral delivery of dsRNA using chitosan nanoparticles has been reported in An.
Building on previous experience with other insects, we adapted the bacterial delivery of dsRNA as a feasible RNAi methodology in mosquito larvae. Therefore, these methodologies can be adapted to aid in many strategies of vector control for different diseases.
How this reduction in AgdsxF transcript interferes with development is poorly understood. In Ae. It is possible that in An. Further work to characterize the cellular processes affected by the gene in An. One of the main findings of this work is the total reduction of the adult females in the treatment group fed with AgdsxF dsRNA. The lifespan of females produced in the AgdsxF dsRNA treatments is also significantly compromised which could mean that if there were female contaminants, they would likely die sooner in the field.
The lack of sperm suggested an unsuccessful mating. More information about the sex differentiation pathway in An. Coupling the effect of this specific construct with short hairpin RNAs will be investigated to determine if a stronger effect on phenotypes can be achieved. In summary, feeding larvae with an appropriate target sequence of AgdsxF dsRNA is a promising method for removing females from cohorts of mass reared An. This technology is especially appealing for regions where the continuous exposure to insecticides has made the vectors resistant to traditional control methods.
Future studies will focus on improving silencing and dsRNA delivery to facilitate the production of male mosquitoes for release in SIT, gene drive, or other alternative vector control methods. Knockdown of AgdsxF in An. The total number of adult females was reduced, and their lifespan and fecundity were also negatively affected.
Nevertheless, the life-span reduction was not enough to suggest a significant impact on parasite transmission. Fertility was also reduced, but sterility was not achieved. More information about the sex differentiation pathway is still needed, as some parts remain poorly understood. Coupling the effect of this specific construct with different gene targets could potentially result on a stronger effect.
This technology for female elimination is particularly useful in new methods in which only males are released. Such methods are promising where the continuous exposure to insecticides has selected for resistance to traditional control methods. World Malaria Report. Geneva: World Health Organization; Takken W, Verhulst NO. Host preferences of blood-feeding mosquitoes. Annu Rev Entomol. No accounting for taste: host preference in malaria vectors.
Trends Parasitol. Anopheles gambiae immune responses to human and rodent Plasmodium parasite species. PLoS Pathog. Multiple blood meals as a reproductive strategy in Anopheles Diptera: Culicidae.
J Med Entomol. Transcription regulation of sex-biased genes during ontogeny in the malaria vector Anopheles gambiae. PLoS One. Dynamics of multiple insecticide resistance in the malaria vector Anopheles gambiae in a rice growing area in south-western Burkina Faso. Malar J. Malaria modeling in the era of eradication. Cold Spring Harb Perspect Med.
Alphey L. Genetic control of mosquitoes. Shaw WR, Catteruccia F. Vector biology meets disease control: using basic research to fight vector-borne diseases. Nat Microbiol. Sterile insect technique: principles and practice in area-wide integrated pest management.
Berlin: Springer; Sterile-insect methods for control. Vector Borne Zoonotic Dis. Does mosquito mass-rearing produce an inferior mosquito?
The first releases of transgenic mosquitoes: an argument for the sterile insect technique. Sex separation strategies: past experience and new approaches. Exploiting intimate relationships: controlling mosquito-transmitted disease with Wolbachia.
Sex-determining mechanisms in insects. Int J Dev Biol. A molecular analysis of doublesex, a bifunctional gene that controls both male and female sexual differentiation in Drosophila melanogaster.
Genes Dev. Evidence for evolutionary conservation of sex-determining genes. Kopp A. Dmrt genes in the development and evolution of sexual dimorphism.
Trends Genet. Insect sex determination: it all evolves around transformer. Curr Opin Genet Dev. Direct targets of the D. Sex- and tissue-specific functions of drosophila doublesex transcription factor target genes. Dev Cell. Identification of sex-specific transcripts of the Anopheles gambiae doublesex gene. J Exp Biol. Molecular cloning, characterization and expression analysis of sex determination gene doublesex from Anopheles gambiae Diptera: Culicidae.
Acta Entomol Sin. Genomic organization and splicing evolution of the doublesex gene, a Drosophila regulator of sexual differentiation, in the dengue and yellow fever mosquito Aedes aegypti. BMC Evol Biol. Characterization of the doublesex gene within the Culex pipiens complex suggests regulatory plasticity at the base of the mosquito sex determination cascade. Silencing the buzz: a new approach to population suppression of mosquitoes by feeding larvae double-stranded RNAs.
Parasit Vectors. Nat Biotechnol. Ingestion of bacterially expressed dsRNAs can produce specific and potent genetic interference in Caenorhabditis elegans. Huvenne H, Smagghe G. J Insect Physiol. Ingested double-stranded RNAs can act as species-specific insecticides. Insect Biochem Mol Biol. Genome-wide RNAi screen identifies genes involved in intestinal pathogenic bacterial infection. Insect Mol Biol. An inexpensive and effective larval diet for Anopheles arabiensis Diptera : Culicidae : eat like a Horse, a bird, or a fish?
Doublesex dsx is doble gene that is involved in the sex determination doble of many doble including the fruit fly Sex melanogaster. The gene sex expressed in both male and female flies and is subject to alternative splicingproducing the protein isoforms dsx f in doble and the longer dsx m in males. Sex production of dsx f ddoble caused by the presence of the female-specific version of the transformer tra gene.
In a sense, doble isoform sex dsx informs a cell about the organism's sex; for instance, female genitals only develop if dsx f wex present. In conjunction with the gene fruitlessdsx also causes differences in the brain sxe and behavior of males and females. Although the details of sex determination differ in the various species, there is a doble related to dsx in vertebrates DMRT1 and in nematodes Sex All of these are transcription factors with sex zinc finger DNA-binding domain known as the DM domain sex are involved in sex-specific differentiation.
From Wikipedia, the free encyclopedia. Sex Categories : Drosophila melanogaster genes Insect proteins Sex-determination systems Developmental genes and proteins.
Dating profiles and free personals ads posted by single women and girls from cities including: Kiev, Moscow, Donetsk, Dnebrovsky, Saint Petersburg, Odessa, Kazan, Perm', Zaporizhzhya, Tambov, Lapu-Lapu City, Guangzhou, Tacloban City, Konakovo, Kalibo, Nizhniy Novgorod, Istanbul, Kharkiv, Brooklyn, Mira Loma,
Doublesex and fruitless are both characterized in mosquitoes and could be used as targets to manipulate the sex of mosquitoes. It is possible to ectopically. , UniRef90_A0A0A1XHA8 · Doublesex protein isoform · ZEUTA. Doublesex · BACRY. Protein doublesex · CERCA. Protein doublesex.
- Вы ищете знакомства с иностранцами?
- Хотите выйти замуж за рубеж?
- Наш международный сайт знакомств абсолютно бесплатно поможет вам!
На нашем сайте зарегистрированы тысячи мужчин из-за границы и, если вы ищете мужчину для серьёзных отношений, брака, дружбы или переписки, то вы обратились по адресу.
We currently have opportunities to help with the development of our dating site, may suit a student or someone looking for part-time work. View more information here.