Derr L K, Strathern J N
Laboratory of Eukaryotic Gene Expression, NCI Frederick Cancer Research and Development Center, Maryland 21702.
Nature. 1993 Jan 14;361(6408):170-3. doi: 10.1038/361170a0.
Recombination between a diffusible reverse transcript and its homologous chromosomal allele has been proposed as a mechanism for the precise removal of introns from DNA and gene conversion of dispersed repeated sequences. We have reported that RNA-mediated recombination occurs in the yeast Saccharomyces cerevisiae. This recombination requires expression of the retrotransposon Ty, and results in intron loss from a plasmid-borne marker gene and the formation of pseudogenes. Because the pseudogenes are embedded in Ty sequences, chromosomal insertion could have been mediated by Ty integrase or by homologous recombination with endogenous Ty sequences. The structure of the chromosomal recombinants and the fact that plasmid and chromosomal recombination can have different requirements demanded a direct demonstration of RNA-mediated gene conversion of a chromosomal allele. Here we report the first demonstration, to our knowledge, of recombination between a reverse transcript and its chromosomal homologue and describe an assay that specifically detects this novel recombination pathway.
一种可扩散的逆转录产物与其同源染色体等位基因之间的重组被认为是从DNA中精确去除内含子以及分散重复序列基因转换的一种机制。我们已经报道RNA介导的重组发生在酿酒酵母中。这种重组需要反转录转座子Ty的表达，并导致质粒携带的标记基因内含子缺失以及假基因的形成。由于假基因嵌入Ty序列中，染色体插入可能是由Ty整合酶介导的，也可能是与内源性Ty序列的同源重组介导的。染色体重组体的结构以及质粒和染色体重组可能有不同要求这一事实，要求直接证明RNA介导的染色体等位基因的基因转换。在此，据我们所知，我们首次证明了逆转录产物与其染色体同源物之间的重组，并描述了一种专门检测这种新型重组途径的检测方法。
