Wilhelm M, Boutabout M, Heyman T, Wilhelm F X
Unité Propre de Recherches 9002 du Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, Strasbourg, 67084, France.
J Mol Biol. 1999 May 14;288(4):505-10. doi: 10.1006/jmbi.1999.2723.
Replication of the yeast Ty1 retrotransposon occurs by a mechanism similar to that of retroviruses. According to the current model of retroviral reverse transcription, two strand transfers (the so-called minus-strand and plus-strand strong-stop DNA transfers) are required to produce full-length preintegrative DNA. Because two genomic RNA molecules are packaged inside the viral particles, the strand transfers can be either intra- or intermolecular. To study the mode of transfer of minus-strand strong-stop DNA during reverse transcription of the yeast Ty1 retrotransposon, we have analyzed the cDNA products that accumulate in the cytoplasmic virus-like particles of yeast cells harboring two marked Ty1 elements. Our results indicate that Ty1 minus-strand transfer occurs in a random manner with approximately similar frequencies of intra- and intermolecular transfer. It has been observed recently that intra- and intermolecular minus-strand transfer occur at similar frequencies during replication of a complex retrovirus such as HIV-1. These results together with the observation that genetic recombination occurs with a high frequency during minus-strand synthesis suggest that both packaged RNA molecules are needed for the synthesis of one minus-strand DNA.
酵母Ty1逆转录转座子的复制机制与逆转录病毒相似。根据目前的逆转录病毒逆转录模型，产生全长整合前DNA需要两次链转移（即所谓的负链和正链强终止DNA转移）。由于两个基因组RNA分子被包装在病毒颗粒内，链转移可以是分子内的，也可以是分子间的。为了研究酵母Ty1逆转录转座子逆转录过程中负链强终止DNA的转移模式，我们分析了在含有两个标记Ty1元件的酵母细胞的细胞质类病毒颗粒中积累的cDNA产物。我们的结果表明，Ty1负链转移以随机方式发生，分子内和分子间转移频率大致相似。最近观察到，在诸如HIV-1这样的复杂逆转录病毒复制过程中，分子内和分子间负链转移以相似频率发生。这些结果以及负链合成过程中高频发生基因重组的观察结果表明，合成一条负链DNA需要两个包装的RNA分子。
