RAPID DEGRADATION OF POLYADENYLATED OOP RNA

The oop RNA is a short (77 nucleotides (nt)) transcript encoded by bac teriophage lambda which acts as an antisense RNA for lambda cll gene e xpression. Recently we demonstrated that oop RNA is specifically polya denylated gt its 3' end by poly(A) polymerase I (PAP I), the pcnB gene product. Here we demonstrate that the half life of oop RNA is 3 times longer in the pcnB mutant relative to the pcnB(+) host, indicating th at polyadenylation of this transcript causes its accelerated degradati on. Although it was proposed that polyadenylation of RNAs in bacteria leads to their enhanced degradation, in most cases stabilization of th ese molecules was observed only when other mutations (pnp, lab and rpe ) were present in the pcnB(-) strain. Therefore it seems that oop RNA may serve as a very useful model in further studies on molecular mecha nisms of RNA polyadenylation and degradation in bacteria, Analysis of oop RNA and its degradation product isolated from Escherichia coli cel ls suggests that both polyadenylated and non-modified oop transcripts can act as antisense RNA. (C) 1998 Federation of European Biochemical Societies.