Functional conservation of the Sex-lethal sex determining promoter, Sxl-Pe, in Drosophila virilis
Tóm tắt
The primary sex determination signal in Drosophila melanogaster, the ratio of X chromosomes to autosomes, sets the activity state of the switch gene, Sex-lethal (Sxl), by regulating the establishment promoter, m-Sxl-Pe. We have identified and characterized the establishment promoter, v-Sxl-Pe, of the distantly related species Drosophila virilis. Like melanogaster, the virilis Sxl-Pe is organized into four sub-domains: the Sxl-Pe mRNA leader and exon E1 of Sxl protein, the core promoter, the sex-specific element and the augmentation element. The core promoter and sex-specific element of v-Sxl-Pe show considerable sequence similarity to m-Sxl-Pe and contain target sites for components of the X/A signaling system. While the augmentation element of v-Sxl-Pe also has sequence motifs that could function as target sites for the X/A signaling system, it shows little similarity to the melanogaster augmentation element. Functional studies reveal that v-Sxl-Pe drives sex-specific expression in D. melanogaster embryos and that the activity of the virilis promoter is controlled by known components of the melanogaster X/A counting system. Although v-Sxl-Pe responds appropriately to the melanogaster sex determination signal, it is less active than Sxl-Pe from melanogaster. Unexpectedly, the reduced activity is due to differences in the activity of the conserved core promoter, while the non-conserved augmentation element functions effectively. These findings suggest that low-affinity target sites for the X/A counting system are critical for the functioning of Sxl-Pe.
Tài liệu tham khảo
Bopp D, Calhoun G, et al (1996) Sex-specific control of Sex-lethal is a conserved mechanism for sex determination in the genus Drosophila. Development 122(3):971–982
Cline TW, Meyer BJ (1996) Vive la difference: males vs females in flies vs worms. Annu Rev Genet 30:637–702
Deshpande G, Calhoun G, et al (1999) The N-terminal domain of Sxl protein disrupts Sxl autoregulation in females and promotes female-specific splicing of tra in males. Development 126(13):2841–2853
Erickson JW, Cline TW (1998) Key aspects of the primary sex determination mechanism are conserved across the genus Drosophila. Development 125(16):3259–3268
Estes PA, Keyes LN, et al (1995) Multiple response elements in the Sex-lethal early promoter ensure its female-specific expression pattern. Mol Cell Biol 15(2):904–917
Harrison DA, McCoon PE, et al (1998) Drosophila unpaired encodes a secreted protein that activates the JAK signaling pathway. Genes Dev 12(20):3252–3263
Hoshijima K, Kohyama A, et al (1995) Transcriptional regulation of the Sex-lethal gene by helix-loop-helix proteins. Nucleic Acids Res 23(17):3441–3448
Jinks TM, Polydorides AD, et al (2000) The JAK/STAT signaling pathway is required for the initial choice of sexual identity in Drosophila melanogaster. Mol Cell 5(3):581–587
Keyes LN, Cline TW, et al (1992) The primary sex determination signal of Drosophila acts at the level of transcription. Cell 68(5):933–943
Meise M, Hilfiker-Kleiner D, et al (1998) Sex-lethal, the master sex-determining gene in Drosophila, is not sex-specifically regulated in Musca domestica. Development 125(8):1487–1494
Muller-Holtkamp F (1995) The Sex-lethal gene homologue in Chrysomya rufifacies is highly conserved in sequence and exon-intron organization. J Mol Evol 41(4):467–477
Penalva LO, Sakamoto H, et al (1996) Regulation of the gene Sex-lethal: a comparative analysis of Drosophila melanogaster and Drosophila subobscura. Genetics 144(4):1653–1664
Saccone G, Peluso I, et al (1998) The Ceratitis capitata homologue of the Drosophila sex-determining gene sex-lethal is structurally conserved, but not sex-specifically regulated. Development 125(8):1495–1500
Salz HK, Maine EM, Keyes LN, Samuels ME, Cline TW, Schedl P (1989) The Drosophila female-specific sex-determination gene, Sex-lethal, has stage-, tissue-, and sex-specific RNAs suggesting multiple modes of regulation. Genes Dev 3:708–719
Sefton L, Timmer JR, et al (2000) An extracellular activator of the Drosophila JAK/STAT pathway is a sex-determination signal element. Nature 405(6789):970–973
Sievert V, Kuhn S, et al (2000) Sequence conservation and expression of the sex-lethal homologue in the fly Megaselia scalaris. Genome 43(2):382–390
Thummel CS, Boulet AM, et al (1988) Vectors for Drosophila P-element-mediated transformation and tissue culture transfection. Gene 74(2):445–456
Winston RL, Millar DP, et al (1999) Characterization of the DNA binding properties of the bHLH domain of Deadpan to single and tandem sites. Biochemistry 38(16):5138–5146
Yang D, Lu H, et al (2001) Interpretation of X chromosome dose at Sex-lethal requires non-E-box sites for the basic helix-loop-helix proteins SISB and daughterless. Mol Cell Biol 21(5):1581–1592
Yanowitz JL, Deshpande G, et al (1999) An N-terminal truncation uncouples the sex-transforming and dosage compensation functions of sex-lethal. Mol Cell Biol 19(4):3018–3028