Postmaturational Cleavage of 23 s Ribosomal Ribonucleic Acid and Its Metabolic Control in the Blue-Green Alga Anacystis nidulans

Abstract

Data are presented consistent with the notion that the 23 s ribosomal ribonucleic acid (rRNA) of Anacystis nidulans undergoes specific endonucleolytic cleavage in vivo, to produce two fragments with molecular weights of 0.88 × 10 6 and 0.17 × 10 6 daltons. Cleavage occurred at random after 23 s rRNA formation and was stimulated by light in this organism, an obligately photoautotrophic unicellular blue-green alga. The half-life of intact 23 s rRNA was about 5 h in illuminated cultures and 10 h in unilluminated cultures. 3-( p -Chlorophenyl)-1, 1-dimethylurea, an inhibitor of photosystem II, retarded 23 s rRNA cleavage in the light. The results are discussed in the context of recent reports of rRNA instability in a variety of eukaryotic and prokaryotic organisms.