| Popis: |
We have previously described isolation of suppressors to a temperature-sensitive mutation of ribosomal protein S12; one such suppressor mutation was found to be an alteration of the RNaseIII gene on the E. coli chromosome (Nashimoto, et al., 1985; Nashimoto & Uchida, 1985). In these studies, a series of cold-sensitive mutations defective in the assembly of ribosomes at 20°C was isolated by localized mutagenesis of a region near the me gene on the E. coli chromosome. The genes defined by the cold sensitive mutations were named rbaA and rbaB, for ribosome assembly. Although both of these genes map close to the me gene on the E. coli chromosome, at least rbaB was found to be definitely different from the me gene. Both of the rba genes accumulated premature ribosomal subunits during growth at 20°C. Otherwise, they were not characterized further at that time. Now, they were mapped more precisely, the genes cloned, and their nucleotide sequence determined. |
