Kim K, Meyer R J
Nucleic Acids Res. 1986 Oct 24;14(20):8027-46. doi: 10.1093/nar/14.20.8027.
We have shown previously [Kim, K. and Meyer, R.J. (1985) J. Mol. Biol. 185,755-767] that copy-number of the broad host-range plasmid R1162 is controlled by the amounts of two proteins, encoded by cotranscribed genes comprising a region of the plasmid called RepI. We have now demonstrated that expression of RepI is negatively regulated by a 75 base RNA that is complementary to a segment of the RepI message. Increased intracellular amounts of RNA molecules that include this segment relieve the inhibition of RepI gene expression, suggesting that the target for regulation is the mRNA itself. A mutation decreasing the amount of the 75 base RNA results in elevated plasmid copy-number. Thus, consistent with our previous observations, regulation of the expression of the RepI genes is a factor in controlling plasmid copy-number.
我们之前已经表明[Kim, K.和Meyer, R.J. (1985)《分子生物学杂志》185, 755 - 767]，广宿主范围质粒R1162的拷贝数由两种蛋白质的量控制，这两种蛋白质由共转录基因编码，这些基因组成了质粒中一个名为RepI的区域。我们现在已经证明，RepI的表达受到一种75个碱基的RNA的负调控，该RNA与RepI信息的一段互补。包含该片段的RNA分子细胞内含量增加会解除对RepI基因表达的抑制，这表明调控的靶标是mRNA本身。一个降低75个碱基RNA量的突变会导致质粒拷贝数升高。因此，与我们之前的观察结果一致，RepI基因表达的调控是控制质粒拷贝数的一个因素。
