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

Abstract

Sexually dimorphic characters have two-fold complexities in pattern formation as they have to get input from both somatic sex determination as well as the positional determining regulators. Sex comb development in Drosophila requires functions of the somatic sex-determining gene doublesex and the homeotic gene Sex combs reduced. Attempts have not been made to decipher the role of dsx in imparting sexually dimorphic expression of SCR and the differential function of sex-specific variants of dsx products in sex comb development. Our results in this study indicate that male-like pattern of SCR expression is independent of dsx function, and dsx F must be responsible for bringing about dimorphism in SCR expression, whereas dsx M function is required with Scr for the morphogenesis of sex comb.[Devi TR and Shyamala BV 2013 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. J. Biosci. 38 [455][456][457][458][459][460]

Identification and characterization of doublesex in Bemisia tabaci

“…It is well known that dsx is a terminal transcription factor in the sex determination pathway and influences the development of both behavioural and morphological secondary sex characteristics by regulating the sex‐specific gene expression of downstream target genes during development (Kijimoto et al ., ; Devi & Shyamala, ). In our research, when Btdsx ‐dimer isoforms were silenced by RNAi, the two tail pins of the male genitalia gradually disappeared and the genitalia were severely malformed, suggesting that the Btdsx ‐dimer isoforms are important in the development of male genitalia in B. tabaci .…”

“…Its protein contains two functional domains: an atypical zinc‐finger (znf) (C2H2C4) DNA‐binding domain (DM or OD1) belonging to the doublesex‐ and mab‐3‐related transcription factor gene family (Erdman & Burtis, ), and a dimerization domain (dsx dimer or OD2). This gene influences the development of both behavioural and morphological secondary sex characteristics (Kijimoto et al ., ; Devi & Shyamala, ). dsx is also a terminal transcription factor in the sex determination pathway and regulates sex‐specific gene expression of downstream target genes during development.…”

Sex- and Tissue-Specific Functions of Drosophila Doublesex Transcription Factor Target Genes

“…There is precedent for feedback in sex determination as TRA is a feedback regulator of Sxl (Siera and Cline, 2008). Similarly, predicted targets of DSX such as Sex combs reduced , Abdominal-B ( Abd-B ), and others encode transcription factors known to regulate dsx expression (Chatterjee et al, 2011; Devi and Shyamala, 2013; Tanaka et al, 2011; Wang and Yoder, 2012). Recently, micro-RNAs have been shown to modulate sex determination (Weng et al, 2013) suggesting we are far from understanding even the basic framework for sex determination and differentiation.…”

Characterization of the doublesex gene within the Culex pipiens complex suggests regulatory plasticity at the base of the mosquito sex determination cascade

“…The 5' end of the male-specific region has been shown to exhibit signs of positive selection in the Anastrepha fraterculus species group [ 39 ], however unlike Anastrepha , we find significantly higher levels of peptide evolution (Ka) and potential positively selected sites (Ka/Ks) in the male-specific doublesex transcript as compared to the female-specific and common regions in these closely related mosquitoes. Hughes [ 38 ] proposed a mechanism for this observation based on the fact that 1) doublesex influences not only development of insect genitalia but also of morphological and behavioral secondary sex characteristics [ 56 – 58 ] and 2) these secondary traits are commonly exaggerated and diverge rapidly during sexual selection in response to female choice [ 59 ]. If female choice itself were a product of neutral mutation [ 60 ], the pleiotropic repercussions of evolving linked male characters in response could create “runaway” evolutionary pressures on the male-specific DSX protein and result in the Ka and Ka/Ks patterns witnessed in our data.…”