Kumar C C, Novick R P
Proc Natl Acad Sci U S A. 1985 Feb;82(3):638-42. doi: 10.1073/pnas.82.3.638.
A transcription map of the replication control region of the Staphylococcus aureus plasmid pT181 has been constructed. Two major leftward transcripts, RNA III and RNA IV, start at positions 339 and 413, respectively. These two RNAs can serve as mRNAs for a plasmid-specific replication protein RepC. Two short rightward transcripts, RNA I and RNA II, approximately 85 and 150 nucleotides long, respectively, start at position 246. These rightward transcripts (referred to as countertranscripts) do not appear to be translated but act directly as negative regulators of plasmid replication, probably by interfering with translation of the RepC mRNAs. There is no significant base sequence homology among the countertranscripts of pT181, ColE1, and R1/NR1/R6-5, suggesting that the structural parallelism has risen by convergent molecular evolution.
已构建出金黄色葡萄球菌质粒pT181复制控制区的转录图谱。两个主要的向左转录本RNA III和RNA IV分别起始于第339位和第413位。这两种RNA可作为质粒特异性复制蛋白RepC的信使核糖核酸。两个短的向右转录本RNA I和RNA II，长度分别约为85和150个核苷酸，起始于第246位。这些向右转录本（称为反义转录本）似乎不被翻译，但直接作为质粒复制的负调控因子，可能是通过干扰RepC信使核糖核酸的翻译来实现的。pT181、ColE1以及R1/NR1/R6 - 5的反义转录本之间不存在显著的碱基序列同源性，这表明这种结构上的相似性是通过趋同分子进化产生的。
