DMRT genes encode a conserved family of transcription factors that share a unique DNA binding motif, the DM domain [ (PUBMED:28774758) ]. This domain was first discovered in the doublesex proteins of Drosophila melanogaster [ (PUBMED:9490411) ]. In D. melanogaster the doublesex gene controls somatic sexual differentiation by producing alternatively spliced mRNAs encoding related sex-specific polypeptides [ (PUBMED:8978051) ]. These proteins are believed to function as transcription factors on downstream sex-determination genes, especially on neuroblast differentiation and yolk protein genes transcription [ (PUBMED:1907913) (PUBMED:3046751) ]. The DM domain binds DNA as a dimer, allowing the recognition of pseudopalindromic sequences [ (PUBMED:8978051) (PUBMED:9927589) (PUBMED:10898790) ]. The NMR analysis of the DSX DM domain [ (PUBMED:10898790) ] revealed a novel zinc module containing 'intertwined' CCHC and HCCC zinc-binding sites. The recognition of the DNA requires the carboxy-terminal basic tail which contacts the minor groove of the target sequence.
GO process:
regulation of transcription, DNA-templated (GO:0006355)
Functional and genetic characterization of the oligomerization and DNA binding properties of the Drosophila doublesex proteins.
Genetics. 1996; 144: 1639-52
Display abstract
The doublesex (dsx) gene of Drosophila melanogaster encodes both male-specific (DSXM) and female-specific (DSXF) polypeptides, which are required for normal differentiation of numerous sexually dimorphic somatic traits. The DSX polypeptides are transcription factors and have been shown previously to bind through a zinc finger-like domain to specific sites in an enhancer regulating sex-specific expression of yolk protein genes. We have determined the consensus target sequence for this DNA binding domain to be a palindromic sequence AGNNACTAAATGTNNTC composed of two half-sites around a central (A/T) base pair. As predicted by the symmetric nature of this site, we have found that the DSX proteins exist as dimers in vivo and have mapped two independent dimerization domains by the yeast two-hybrid method; one in the non-sex-specific amino-terminal region of the protein and one that includes the partially sex-specific carboxy-terminal domains of both the male and female polypeptides. We have further identified a missense mutation that eliminates dsx function in female flies, and shown that the same mutation prevents dimerization of DSXF in the yeast two-hybrid system, indicating a critical role for dimerization in dsx function in vivo.
The Drosophila doublesex proteins share a novel zinc finger related DNA binding domain.
EMBO J. 1993; 12: 527-35
Display abstract
The doublesex gene of Drosophila melanogaster is the final member of a well characterized hierarchy of genes that controls somatic sex determination and differentiation. The male-specific and female-specific doublesex polypeptides occupy a terminal position in the hierarchy, and thus regulate those genes responsible for the development of sexually dimorphic characteristics of the fly. To investigate the molecular mechanism by which these two related proteins interact with specific target genes, we have identified and characterized their DNA binding domains. Using gel mobility shift experiments with sequentially deleted polypeptides, site-directed mutagenesis and spectrophotometric assays, we have shown that the two doublesex proteins share a common and novel zinc finger-related DNA binding domain distinct from any reported class of zinc binding proteins. We have further shown that of 10 null dsx alleles, six encode proteins deficient in DNA binding activity, and that three of these alleles are the result of mutations that alter cysteine and histidine residues in the metal binding domain. Our results provide evidence that both the male-specific and female-specific doublesex proteins share and depend upon the same DNA binding domain for function in vivo, suggesting that both proteins bind to, but differentially regulate, a common set of genes in both sexes.
Drosophila doublesex gene controls somatic sexual differentiation by producing alternatively spliced mRNAs encoding related sex-specific polypeptides.
Cell. 1989; 56: 997-1010
Display abstract
The doublesex (dsx) gene regulates somatic sexual differentiation in both sexes in D. melanogaster. Two functional products are encoded by dsx: one product is expressed in females and represses male differentiation, and the other is expressed in males and represses female differentiation. We have determined that the dsx gene is transcribed to produce a common primary transcript that is alternatively spliced and polyadenylated to yield male- and female-specific mRNAs. These sex-specific mRNAs share a common 5' end and three common exons, but possess alternative sex-specific 3' exons, thus encoding polypeptides with a common amino-terminal sequence but sex-specific carboxyl termini. Genetic and molecular data suggest that sequences including and adjacent to the female-specific splice acceptor site play an important role in the regulation of dsx expression by the transformer and transformer-2 loci.
