Involvement of DNA end-binding protein Ku in Ty element retrotransposition.
Saccharomyces cerevisiae Ty elements are retrotransposons whose life cycles are strikingly similar to those of retroviruses. They transpose via an RNA intermediate that is converted to linear double-stranded cDNA and then inserted into the host genome. Although Ty integration is mediated by the element-encoded integrase, it has been proposed that host factors are involved in this process. Here, we show that the DNA end-binding protein Ku, which functions in DNA double-strand break repair, potentiates retrotransposition. Specifically, by using a galactose-inducible Ty1 system, we found that in vivo, Ty1 retrotransposition rates were substantially reduced in the absence of Ku. In contrast, this phenotype was not observed with yeast strains containing mutations in other genes that are involved in DNA repair. We present evidence that Ku associates with Ty1 viruslike particles both in vitro and in vivo. These results provide an additional role for Ku and suggest that it might function in the life cycles of retroelements in other systems.
Downs
J A
JA
Wellcome/CRC Institute and Department of Zoology, Cambridge University, Cambridge CB2 1QR, United Kingdom.
Jackson
S P
SP
D034961:Antigens, Nuclear; D001483:Base Sequence; D004265:DNA Helicases; D017931:DNA Primers / Q000235:genetics; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D007181:Inclusion Bodies, Viral / Q000378:metabolism; D000072200:Ku Autoantigen; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D011995:Recombination, Genetic; D018626:Retroelements / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism* / Q000821:virology; D029701:Saccharomyces cerevisiae Proteins
D034961:Antigens, Nuclear; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D018626:Retroelements; D029701:Saccharomyces cerevisiae Proteins; C081647:high affinity DNA-binding factor, S cerevisiae; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen