Functional conservation of the sex-lethal sex determining promoter, Sxl-Pe, in Drosophila virilis.
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.
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Timothy Morgan
TM
Jinks
Gretchen
G
Calhoun
Paul
P
Schedl
D020121:5' Untranslated Regions; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics; D004625:Embryo, Nonmammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D019849:Sex Determination Processes; D015398:Signal Transduction
D020121:5' Untranslated Regions; D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; C067777:Sxl protein, Drosophila