In vitro analysis of the terminator T-II of the inhibitor antisense rna IIgene from plasmid pMV158

One element involved in the copy number control of plasmid pMV 158 is the a ntisense RNA II. We have determined the precise size of this RNA synthesize d in vitro. Transcript termination occurs at two consecutive template posit ions within a typical rho-independent terminator, T-ll. Using a series of p lasmid derivatives in which the T-ll terminator has been partially or total ly removed, we have analyzed the relationship between the predicted stabili ty of the RNA hairpin encoded by T-ll and the efficiency of in in vitro int rinsic termination. All the plasmids of the pMV158 family, constituted so f ar of 19 replicons. harbor putative antisense RNA-encoding genes which shar e in common the relative location with respect to the essential rrl, gene. the small size, and the presence of rho-independent transcription terminato rs. (C) 2001 Academic Press.