Mapping and characterization of a mutation in Escherichia coli that reduces the level of ribonuclease III specific for double-stranded ribonucleic acid

Abstract

Localization of a mutation affecting ribonuclease III activity (an enzyme specific for double-stranded ribonucleic acid) in Escherichia coli was attempted. By a series of matings and transduction experiments, the mutation rnc-105 was mapped near the nadB gene. In strains carrying this mutation, another mutation (ranA2074) was also found. Based on available data, their order on the E. coli chromosome appears to be tyrA, ranA, nadB, rnc, duction and matings were performed as described previously (4,11,12).Bacteriophage plating. Phage were plated as described previously (4).Assay of RNase III. RNase assays were done as described by Robertson et al. (14), Meyhack et al. (13), and Apirion and Watson (4).Nomenclature. We suggest that genes affecting RNase activities should be referred to as ma, rnb, etc., 317 on July 31, 2020 by guest

Processing of procaryotic ribonucleic acid.

“…Genetic analysis of strain AB301-105 revealed the presence of at least seven mutations other than the RNase III lesion, confirming the original indication that it was not isogenic with the parental strain (17). For study of the effect of the RNase III mutation rnc-105 by itself, the mutation was first mapped at 54.5 min (18,168) (Fig. 5), and isogenic rnc+/rnc-105 pairs were then constructed by transducing the rnc-105 mutation into a different genetic background (18) which allowed further study of the physiological role of RNase III (see below).…”

“…The loci are discussed in the text. rnc, RNase III (18,168); rne, RNase E (9); rnp, RNase P (10, 21, 155a); cca, nucleotidyltransferase (38, 47a). A mutation which affects RNase D (rnd) was mapped at 39.8 min (M. ), and those at the rnpB locus affect the RNA component of RNase P (80).…”

Processing of unstable bacteriophage T4 gene 32 mRNAs into a stable species requires Escherichia coli ribonuclease E.

“…The percentage of surviving bacteria was <2% for the rnp strain, -20% for the rnc+ strain and as high as 40% for the rnc strain. Apirion and Watson (1975) had found that T4 had a reduced ability to infect an rncmutant strain of E.coli.…”

Cloning, sequence analysis, and expression of alteration of the mRNA stability gene (ams+) of Escherichia coli

“…A mutant with low RNase III has been found to stabilize mRNA. The ams gene has been mapped at 23' on the E. coli chromosome (13), but RNase III maps at 55' (1,17). In addition to RNase III, other RNases, RNase I and RNase II, map at 14' and 28' on the E. coli chromosome, respectively (12)(13)(14)(15).…”