Biomaterial Database

Altered DNA-protein relaxation complex in a replication mutant of plasmid ColE1. 1978

J Collins, and S Yanofsky, and D R Helinski

Approximately 200,000 clones of Escherichia coli carrying mutagen-treated colicinogenic plasmid E1 (ColE1) were examined for irreversible loss of the plasmid at 43 degrees. Thirty of these clones that appeared to be most defective in plasmid DNA replication at the non-permissive temperature were selected for the study of: (a) the kinetics of plasmid and chromosomal DNA replication during a temperature shift in either the presence or absence of chloramphenicol; (b) the temperature stability of the plasmid DNA-protein relaxation complex; and (c) the temperature effect on F-promoted conjugal transfer. Two mutant plasmids, pJC307 and pJC301, showed defects in their relaxation complex. The relaxation complex of pJC307 exhibited an altered temperature stability in vitro. Reversion to temperature resistant replication resulted in four out of five cases in a concomitant change in the temperature stability of the relaxation complex. Conjugal mobility of this mutant was not markedly reduced at the permissive or non-permissive temperature. Plasmid pJC301 could not be isolated in the form of a relaxation complex and it was very poorly mobilized in an F'-promoted conjugation. These results indicate that the ColE1 plasmid codes for at least one of the proteins of the relaxation complex and that the relaxation complex is involved in ColE1 DNA replication. In addition, the properties of the mutant plasmid pJC301 are consistent with a role for the complex in the mobilization of ColE1 during conjugation.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010641	Phenotype	The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.	Phenotypes
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D003087	Colicins	Bacteriocins elaborated by strains of Escherichia coli and related species. They are proteins or protein-lipopolysaccharide complexes lethal to other strains of the same species.	Colicin,Colicin E9,Colicine,Colicines,Colicin A,Colicin B,Colicin E,Colicin E1,Colicin E2,Colicin E3,Colicin E8,Colicin HSC10,Colicin Ia,Colicin Ib,Colicin K,Colicin K-K235,Colicin M,Colicin N,Colicin V,Colicins E,Colicins E9,Precolicin E1,Colicin K K235,E9, Colicin
D003227	Conjugation, Genetic	A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.	Bacterial Conjugation,Conjugation, Bacterial,Genetic Conjugation
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot