Inouye S, Hsu M Y, Eagle S, Inouye M
Department of Biochemistry, Robert Wood Johnson Medical School at Rutgers University of Medicine and Dentistry of New Jersey, Piscataway 08854.
Cell. 1989 Feb 24;56(4):709-17. doi: 10.1016/0092-8674(89)90593-x.
Myxobacteria have been shown to produce a peculiar RNA-DNA complex called msDNA, in which a single-stranded DNA is branched out from a RNA molecule (msdRNA) by a 2',5' phosphodiester linkage. It has been predicted that reverse transcriptase is required for msDNA biosynthesis. We identified a gene for reverse transcriptase in M. xanthus in the region that has been demonstrated to code for a cis- or transacting element for msDNA synthesis. This gene is located immediately downstream of the msdRNA coding region, and codes for a polypeptide of 485 amino acid residues. The polypeptide shows sequence similarity with retroviral reverse transcriptases. This fact, together with the mode of msDNA synthesis, suggests a possible relationship between retroviruses and the msDNA system. The analysis of the gene and the distribution of the msDNA system in independent isolates of M. xanthus indicate that the element is as old as other essential genes in M. xanthus and that it was not recently acquired into the genome.
粘细菌已被证明能产生一种名为msDNA的特殊RNA - DNA复合物，其中单链DNA通过2',5'磷酸二酯键从RNA分子（msdRNA）分支出来。据预测，msDNA生物合成需要逆转录酶。我们在黄色粘球菌中已被证明编码msDNA合成的顺式或反式作用元件的区域鉴定出一个逆转录酶基因。该基因位于msdRNA编码区的紧邻下游，编码一个485个氨基酸残基的多肽。该多肽与逆转录病毒逆转录酶具有序列相似性。这一事实，连同msDNA的合成模式，提示了逆转录病毒与msDNA系统之间可能存在的关系。对该基因以及黄色粘球菌独立分离株中msDNA系统分布的分析表明，该元件与黄色粘球菌中的其他必需基因一样古老，并非近期才进入基因组。
