ALTERATION OF RNA-I METABOLISM IN A TEMPERATURE-SENSITIVE ESCHERICHIA-COLI RNPA MUTANT STRAIN

E. coli strain A49 carries the themosensitive mutation in the rnpA gene encoding the protein component of RNase P, a tRNA-processing enzyme. Two small RNAs were highly accumulated in the A49 carrying derivatives of ColEl-type plasmids, at nonpermissive temperature. Characterization of these RNAs showed that they were the processed or degraded products derived from RNA I, which is the negative controller of ColEl-type plasmid replication. These derivatives of RNA I only differ in size at the 5′ ends. The data of their degradation and synthesis kinetics suggest that they are intermediates of RNA I metabolism. © 1992 Academic Press, Inc.