title: Mutations affecting replication and copy number control in plasmid mini-F both reside in the gene for the 29-kDa protein.
abstract: We have isolated and characterized cop, copts, and repam mutants of plasmid mini-F after in vitro mutagenesis with hydroxylamine. cop mutants exhibit a copy number of about 10 per cell. The copts mutants are cold-sensitive and have, at 25 degrees C, a copy number of about 30-40 copies per cell, which drops to 4 copies at 42 degrees C. The cop and repam mutations affect the 29-kDa E protein. The Copts phenotype results from the simultaneous occurrence of two mutations, a cop mutation in the E protein and a temperature-dependent mutation (termed ecp) enhancing the Cop phenotype at low temperature. The latter new type of mutation is located within the DNA region 44.1-44.85F. Complementation experiments with plasmid cointegrates show that the wild-type gene is dominant over the cop allele. The nucleotide sequences of the cop and the repam mutations have been determined.
mesh_terms: D001483:Base Sequence; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D005144:F Factor; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D010641:Phenotype; D012093:Replicon
chemical_list: D004269:DNA, Bacterial