Mutations affecting replication and copy number control in plasmid mini-F both reside in the gene for the 29-kDa protein |
| |
Authors: | M Helsberg J Ebbers R Eichenlaub |
| |
Affiliation: | 1. Ruhr-Universität Bochum, Lehrstuhl Biologie der Mikroorganismen, Postfach 10 21 48, D-4630 Bochum 1, Federal Republic of Germany;1. Universität Hamburg, Institut für Allgemeine Botanik, Ohnhorststrasse 18, D-2000 Hamburg 52, Federal Republic of Germany |
| |
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. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|