ABSTRACT

RNA stability, determined by the rates of transcription and degradation, is a major constituent of the control of gene expression in the chloroplast. The molecular mechanism of the degradation pathway has been largely uncovered in the past few years. It includes endonucleolytic cleavage, polyadenylation of the cleavage product and only then exonucleolytic degradation. This mechanism was found to be general for prokaryotes and the choloroplast. However, exploring the molecular details of the RNA degradation pathway in E. coli, cyanobacteria and the chloroplast revealed several differences hinting at evolutionary relationships of this molecular mechanism for RNA degradation.