Zhang S P, Yan L F, Zubay G
Fairchild Center for Biological Sciences, Columbia University, New York, New York 10027.
J Bacteriol. 1988 Dec;170(12):5460-7. doi: 10.1128/jb.170.12.5460-5467.1988.
cea, imm, and kil are a cluster of three functionally related genes of the plasmid ColE1. The cea and kil genes are in the same inducible operon, with transcription being initiated from a promoter adjacent to the cea gene. The imm gene is located between the cea and kil genes, but it is transcribed in the opposite direction. Complementary interaction between the imm mRNA and the anti-imm sequences in the middle of the cea-kil transcript causes a pronounced delay in expression of the kil gene when the cea-kil operon is induced. A segment in the overlapping region between the cea and imm genes causes delayed expression of the kil gene in the absence of imm gene transcription. This delay effect increases the yields of colicin synthesized in induced cells.
cea、imm和kil是质粒ColE1上一组功能相关的三个基因。cea和kil基因位于同一个可诱导操纵子中，转录从与cea基因相邻的启动子开始。imm基因位于cea和kil基因之间，但转录方向相反。当cea - kil操纵子被诱导时，imm mRNA与cea - kil转录本中间的抗imm序列之间的互补相互作用导致kil基因的表达明显延迟。在没有imm基因转录的情况下，cea和imm基因重叠区域的一个片段会导致kil基因表达延迟。这种延迟效应提高了诱导细胞中合成的大肠杆菌素的产量。
