POLYADENYLATION OF OOP RNA IN THE REGULATION OF BACTERIOPHAGE-LAMBDA DEVELOPMENT

We have shown that Escherichia coli pcnB mutants are lysogenized by ba cteriophage lambda with lower efficiency as compared to the pcnB(+) st rains. Our genetic analysis revealed that expression of the lambda cII gene is decreased in the pcnB mutants. However, using various lacZ fu sions we demonstrated that neither activities of p(L) and p(R) promote rs nor transcription termination at t(R1) were significantly impaired in the pcnB(-) host. On the other hand, we found that oop RNA, an anti sense RNA for cll expression, is involved in this regulation. Primer p rotection experiments revealed that oop RNA was polyadenylated and tha t this polyadenylation was impaired in the pcnB mutant. We found that the oop RNA was more abundant in the pcnB mutant than in the pcnB(+) s train. Furthermore, we showed that activity of the p(0) promoter was n ot stimulated in the pcnB mutant. Such findings indicated that degrada tion of oop RNA in the pcnB strain was slower because of inefficient p olyadenylation, which could lead to more effective inhibition of cII e xpression by the antisense oop RNA, resulting in less efficient lysoge nization of the;host. The oop RNA was found previously to play a role in phage lambda development only under conditions of overproduction of this transcript. Here we demonstrate for the first time, the physiolo gical function of oop RNA in lambda development, confirming that this short transcript plays an important role in the negative regulation of cII gene expression during lambda infection. Moreover, polyadenylatio n of oop RNA is one of very few known examples of specific RNA polyade nylation by PAP I in prokaryotic cells and its role in gene expression regulation. (C) 1998 Elsevier Science B.V. All rights reserved.