Lauermann V, Nam K, Trambley J, Boeke J D
Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
J Virol. 1995 Dec;69(12):7845-50. doi: 10.1128/JVI.69.12.7845-7850.1995.
Reverse transcription in the yeast retrotransposon Ty1 follows the general "rules" of retroviral replication overall. However, some details of the retroviral and Ty1 reverse transcription processes are different. We have identified and determined the structure of plus-strand strong-stop DNA and examined the effect of polypurine tract deletion mutations on its synthesis. Furthermore, we have defined the stop signal for plus-strand strong-stop DNA synthesis as an unusual 2'-O-ribosylated nucleotide in the primer tRNA. Full-length plus-strand strong-stop DNA, following strand transfer, would have a terminal 2-base mismatch with minus-strand DNA. These findings indicate that the mechanism of plus-strand strong-stop DNA transfer in Ty1 differs from that of the retroviral transfer and suggest that full-length plus-strand strong-stop DNA is not a direct intermediate in Ty1 retrotransposition.
酵母逆转座子Ty1中的逆转录总体上遵循逆转录病毒复制的一般“规则”。然而,逆转录病毒和Ty1逆转录过程的一些细节有所不同。我们已经鉴定并确定了正链强终止DNA的结构,并研究了聚嘌呤序列缺失突变对其合成的影响。此外,我们将正链强终止DNA合成的终止信号定义为引物tRNA中一种不寻常的2'-O-核糖基化核苷酸。链转移后,全长正链强终止DNA与负链DNA会有一个末端2碱基错配。这些发现表明,Ty1中正链强终止DNA转移的机制与逆转录病毒转移的机制不同,并表明全长正链强终止DNA不是Ty1逆转座过程中的直接中间体。