Doublesex Functions Early and Late in Gustatory Sense Organ Development

David J Mellert,Carmen C Robinett,Bruce S Baker,Edward Giniger

doi:10.1371/journal.pone.0051489

David J Mellert, Carmen C Robinett + Show 2 more

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https://doi.org/10.1371/journal.pone.0051489

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Abstract

Somatic sexual dimorphisms outside of the nervous system in Drosophila melanogaster are largely controlled by the male- and female-specific Doublesex transcription factors (DSXM and DSXF, respectively). The DSX proteins must act at the right times and places in development to regulate the diverse array of genes that sculpt male and female characteristics across a variety of tissues. To explore how cellular and developmental contexts integrate with doublesex (dsx) gene function, we focused on the sexually dimorphic number of gustatory sense organs (GSOs) in the foreleg. We show that DSXM and DSXF promote and repress GSO formation, respectively, and that their relative contribution to this dimorphism varies along the proximodistal axis of the foreleg. Our results suggest that the DSX proteins impact specification of the gustatory sensory organ precursors (SOPs). DSXF then acts later in the foreleg to regulate gustatory receptor neuron axon guidance. These results suggest that the foreleg provides a unique opportunity for examining the context-dependent functions of DSX.

Highlights

Studies in Drosophila melanogaster have revealed that many complex biological processes, such as the specification of somatic structures [1,2], segmental identity [3], and sexual differentiation [4,5], are under the control of master regulatory genes
We revisited the T1 dimorphism and asked if dsx regulates the number of gustatory sense organs (GSOs) in T2–T4 by examining the forelegs of males and females that are null for dsx function and comparing them to those with one wild-type copy of dsx
Dsx null flies exhibited no significant differences between males and females in the numbers of GSOs in foreleg T1–T4 (Fig. 1E), indicating that sex-specific dsx functions are necessary for this sexual dimorphism

Summary

Introduction

Studies in Drosophila melanogaster have revealed that many complex biological processes, such as the specification of somatic structures [1,2], segmental identity [3], and sexual differentiation [4,5], are under the control of master regulatory genes These genes may act at multiple times in the course of these processes to regulate the expression of distinct sets of target genes. DSXM and DSXF contain a shared zinc finger DNA-binding domain but differ in having sex-specific C-termini [7,8,9] They are thought to bind to, and sex- regulate the transcription of, a common set of target genes. The chromosomal sex of a cell determines the sexspecific functions of dsx via post-transcriptional mechanisms

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