Drosophila IRBP/Ku p70 corresponds to the mutagen-sensitive mus309 gene and is involved in P-element excision in vivo.
The P family of transposable elements in Drosophila transpose by a cut-and-paste mechanism involving double-strand gap repair. We report here that a Drosophila mutagen-sensitive mutant, mus3O9, contains a mutation in IRBP (inverted repeat binding protein), the Drosophila homolog of the mammalian Ku p70 gene. We show that the repair of double-strand DNA breaks after P-element excision is severely reduced in mus3O9 mutants using an in vivo assay for P-element transposase activity. In addition, excision products recovered from mus3O9 mutant embryos by use of a plasmid-based P-element mobility assay contain large deletions, suggesting that IRBP is involved in the repair of double-strand DNA breaks. Our findings provide the first demonstration that a mutation in the IRBP gene affects double-strand DNA break repair and suggest that DNA repair functions are conserved between Drosophila and mammals.
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Department of Molecular and Cell Biology, University of California, Berkeley, 94720-3204, USA.
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D000818:Animals; D034961:Antigens, Nuclear; D001483:Base Sequence; D004265:DNA Helicases; D004260:DNA Repair; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000502:physiology*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D017344:Genes, Insect; D005816:Genetic Complementation Test; D000072200:Ku Autoantigen; D008297:Male; D008969:Molecular Sequence Data; D009153:Mutagens; D009687:Nuclear Proteins / Q000502:physiology; D012091:Repetitive Sequences, Nucleic Acid
D034961:Antigens, Nuclear; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C086846:Irbp protein, Drosophila; D009153:Mutagens; D009687:Nuclear Proteins; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen