Karst S M, Rütz M L, Menees T M
Department of Cell Biology, School of Biological Sciences, Kansas City, Missouri, 64110, USA.
Biochem Biophys Res Commun. 2000 Feb 5;268(1):112-7. doi: 10.1006/bbrc.1999.2048.
A mutant screen has been initiated to identify host genes important for the replication of retrotransposons in Saccharomyces cerevisiae. Two mutants were identified that undergo Ty1 and Ty3 transposition at <10% of the wild-type frequency. Both these mutants have deficiencies in the accumulation of full-length Ty1 and Ty3 cDNAs, although Ty proteins (including reverse transcriptase) accumulate at wild-type levels. The DBR1 gene, encoding the yeast debranching enzyme, complements both mutants. This suggests that Dbr1p is important for either reverse transcription or the stability of Ty cDNA, roles that have not been previously reported for this protein. The deficiency in accumulation of Ty cDNAs in dbr1 mutants is apparent when engineered Ty elements are expressed for short time periods (6-10 h) but is not apparent following long expression periods (>24 h).
已启动一项突变体筛选，以鉴定酿酒酵母中对逆转座子复制重要的宿主基因。鉴定出两个突变体，其Ty1和Ty3转座频率低于野生型频率的10%。尽管Ty蛋白（包括逆转录酶）以野生型水平积累，但这两个突变体在全长Ty1和Ty3 cDNA的积累方面均存在缺陷。编码酵母去分支酶的DBR1基因可互补这两个突变体。这表明Dbr1p对逆转录或Ty cDNA的稳定性很重要，此前尚未报道该蛋白具有这些作用。当工程化的Ty元件短时间（6 - 10小时）表达时，dbr1突变体中Ty cDNA积累的缺陷很明显，但长时间（>24小时）表达后则不明显。
