Molecular identification of virilizer, a gene required for the expression of the sex-determining gene Sex-lethal in Drosophila melanogaster.
Sex-lethal (Sxl) is a central switch gene in somatic sexual development of Drosophila melanogaster. Female-specific expression of Sxl relies on autoregulatory splicing of Sxl pre-mRNA by SXL protein. This process requires the function of virilizer (vir). Besides its role in Sxl splicing, vir is essential for male and female viability and is also required for the production of eggs capable of embryonic development. We have identified vir molecularly and found that it produces a single transcript of 6 kb that is ubiquitously expressed in male and female embryos throughout development. This transcript encodes a nuclear protein of 210 kD that cannot be assigned to a known protein family. VIR contains a putative transmembrane domain, a coiled-coil region and PEST sequences. We have characterized five different alleles of vir. Those alleles that affect both sexes are associated with large truncations of the protein, while alleles that affect only the female-specific functions are missense mutations that lie relatively close to each other, possibly defining a region important for the regulation of Sxl.
Niessen
M
M
Zoological Institute, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Schneiter
R
R
Nothiger
R
R
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005091:Exons; D005260:Female; D015723:Gene Library; D017403:In Situ Hybridization; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes
D029721:Drosophila Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C067777:Sxl protein, Drosophila; C425767:vir protein, Drosophila