title: Cloning of a 1.1-kb fragment including srnB+ gene in the F plasmid and isolation of an srnB mutant.
abstract: The srnB+ gene, promoting stable RNA degradation at 42 C in the presence of rifampin, was cloned by using pBR322 as a vector; it was located on a 1.1-kilobase (kb) Eco RI/Bam HI fragment between 1.4 and 2.5 kb of the F plasmid. The region between 93.3 and 4.0 kb of the F plasmid was physically mapped by using restriction endonucleases EcoRI, HindIII, BamHI, PstI, and SmaI, with reference to a standard HindIII site in IS3. An srnB1 mutant was isolated from a chimeric plasmid, pOY54, after treatment of its DNA with hydroxylamine. The srnB1 allele on the F fragment of the mutant plasmid was recessive to the wildtype allele. Thermal elevation of cell cultures to 39 C was high enough to promote RNA degradation in strain YS12 carrying plasmid pOY54.
mesh_terms: D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics*; D005144:F Factor; D005796:Genes; D005798:Genes, Bacterial; D009154:Mutation; D012329:RNA, Bacterial / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D004262:DNA Restriction Enzymes