A TRANSCRIPTION TERMINATOR SIGNAL NECESSARY FOR PLASMID COLLB-P9 REPLICATION

作者：MORI A; ITO K; MIZOBUCHI K; NAKAMURA Y

来源：Molecular Microbiology, 1995, 17(2): 291-301.

DOI：10.1111/j.1365-2958.1995.mmi_17020291.x

Replication of the Incl alpha plasmid Collb-P9 requires the repZ gene, which encodes an essential, unstable initiator protein termed RepZ. Although many functional features of the Collb-P9 replicon resemble those of structurally unrelated IncFll plasmids R1 and NR1, the role of transcription of repZ towards the replication origin is poorly understood. Using a series of deletion and substitution mutants of the Collb-P9 replicon, we found that RepZ prefers to act in cis and that a spacer sequence between repZ and the origin is required for replication. This spacer element, referred to as CIS, retained strong transcription terminator activity. Efficient transcription terminators, whether Rho-dependent or -independent, were capable of replacing CIS function for in vivo replication; Collb-P9 replicated better as transcription terminated more efficiently within CIS. When the CIS element was substituted for by a strong Rho-dependent terminator, such as lambda tR1 or E. coli trp t', in vivo replication of these recombinant replicons became dependent on the Rho factor, in contrast to the authentic Collb-P9 replicon.

• 出版日期1995-7
• 单位河北医科大学