Interspecies comparison reveals evolution of control regions in the nematode sex-determining gene tra-2.
The Caenorhabditis elegans sex-determining gene tra-2 promotes female development and expresses 4.7-, 1.9- and 1.8-kb mRNAs. The 4.7-kb mRNA encodes the major feminizing activity of the locus, a predicted membrane receptor that mediates cell-to-cell communication, named TRA-2A. The tra-2 gene was characterized from a close relative, C. briggsae. The Cb-tra-2 gene expresses only a 4.7-kb mRNA and alternatively spliced variants, which encode TRA-2A homologues. The Cb-TRA-2A and Ce-TRA-2A sequences are highly diverged, sharing only 43% identity, although their hydropathy profiles remain remarkably similar. Three potential regulatory sites of Ce-tra-2 activity were previously identified by analyzing tra-2(eg), tra-2(gf), and tra-2(mx) mutations. Two of these sites, the EG site and MX region, are conserved in Cb-tra-2. By contrast, the two direct repeat elements in the Ce-tra-2 3' untranslated region, which are disrupted in tra-2(gf) mutants, are absent. Injection of Cb-tra-2 antisense RNA into C.briggsae mimics the Ce-tra-2 loss-of-function phenotype. Thus, antisense RNA permits studies of gene activity in nematodes that lack extensive genetics.
Medical Research Council Laboratory of Molecular Biology, Cambridge, England. pek@mrc-lmb.cam.ac.uk
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Kuwabara
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018509:DNA, Helminth; D019143:Evolution, Molecular; D005260:Female; D015801:Helminth Proteins / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010641:Phenotype; D012313:RNA; D016372:RNA, Antisense; D012045:Regulatory Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012732:Sex Determination Analysis
D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; D015801:Helminth Proteins; D008565:Membrane Proteins; D016372:RNA, Antisense; C076107:tra-2 protein, C elegans; D012313:RNA