Cluster of ribosomal protein genes in Escherichia coli containing genes for proteins S6, S18, and L9.

A mutant of Escherichia coli K-12 isolated for temperature-sensitive growth was found to harbor an alteration in robosomal protein L9. Because the chromosomal location of the structural gene for this protein (rplI) was not known, we mapped the mutation by using various Hfr strains. The fine mapping of this gene by Plkc phage-mediated transductions has revealed that it forms a gene cluster at 94 min on the E. coli genetic map together with the genes coding for two other ribosomal proteins, S6 (rpsF) and S18 (rpsR). Furthermore, the region of the E. coli genetic map containing this cluster was found to be shorter than previously estimated by approximately 2 min.