Department of Molecular Biology, Odense University, Campusvej 55, DK-5230 Odense M, Denmark.
EMBO J. 1982;1(3):323-8. doi: 10.1002/j.1460-2075.1982.tb01168.x.
The copy number control gene, copA, of plasmid R1 codes for an 80-nucleotide untranslatable RNA. In Escherichia coli minicells, some copA hybrid plasmids and R1 miniplasmids also express a transcript of 200 nucleotides. Only the small RNA mediates the CopA phenotype. The switch between 80- and 200-nucleotide RNA synthesis is shown to be caused by convergent transcription; if transcription proceeds in both directions the inactive larger RNA is synthesised; the active small RNA is formed when copA transcription is not opposed by transcription from the other direction. The data presented indicate that convergent transcription interferes with copA expression by abolishing or reducing normal copA transcription termination.
复制数控制基因 copA 位于质粒 R1 上，编码一段 80 个核苷酸的非翻译 RNA。在大肠杆菌小型细胞中，一些 copA 杂种质粒和 R1 小型质粒也表达一段 200 个核苷酸的转录本。只有小 RNA 介导 CopA 表型。80 核苷酸和 200 核苷酸 RNA 合成之间的转换被证明是由转录的趋同引起的；如果转录在两个方向上进行，就会产生无活性的较大 RNA；当 copA 转录不受来自另一个方向的转录的拮抗时，就会形成有活性的小 RNA。所提出的数据表明，趋同转录通过消除或减少正常的 copA 转录终止来干扰 copA 的表达。
