1sxl

Structural highlights

Function

SXL_DROME Sex determination switch protein which controls sexual development by sex-specific splicing. Regulates dosage compensation in females by suppressing hyperactivation of X-linked genes. Expression of the embryo-specific isoform is under the control of primary sex-determining signal, which depends on the ratio of X chromosomes relative to autosomes (X:A ratio). Expression occurs in 2X:2A cells, but not in X:2A cells. The X:A ratio seems to be signaled by the relative concentration of the X-linked transcription factors SIS-A and SIS-B. As a result, the embryo-specific product is expressed early only in female embryos and specifies female-adult specific splicing; in the male where it is not expressed, the default splicing gives rise to a truncated non-functional protein. The female-specific isoform specifies the splicing of its own transcript, thereby initiating a positive autoregulatory feedback loop leading to female development pathway. The female-specific isoform controls the sex-specific splicing of transformer (TRA); acts as a translational repressor for male-specific lethal-2 (MSL-2) and prevents male-less (MLE), MSL-1 and MSL-3 proteins from associating with the female X chromosome.^{[1] [2] [3]}

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

References

1. ↑ Bell LR, Maine EM, Schedl P, Cline TW. Sex-lethal, a Drosophila sex determination switch gene, exhibits sex-specific RNA splicing and sequence similarity to RNA binding proteins. Cell. 1988 Dec 23;55(6):1037-46. PMID:3144435
2. ↑ Samuels ME, Schedl P, Cline TW. The complex set of late transcripts from the Drosophila sex determination gene sex-lethal encodes multiple related polypeptides. Mol Cell Biol. 1991 Jul;11(7):3584-602. PMID:1710769
3. ↑ Keyes LN, Cline TW, Schedl P. The primary sex determination signal of Drosophila acts at the level of transcription. Cell. 1992 Mar 6;68(5):933-43. PMID:1547493