Biomaterial Database

Cloning of gene lon (capR) of Escherichia coli K-12 and identification of polypeptides specified by the cloned deoxyribonucleic acid fragment. 1980

B A Zehnbauer, and A Markovitz

A mutation in the lon (capR) gene of Escherichia coli K-12 results in overproduction of capsular polysaccharide and increased sensitivity to ultraviolet and ionizing radiations. The lon (capR) gene deoxyribonucleic acid was cloned from a new F' factor. The new plasmids, designated pBZ201 and pBZ203, (i) contained an additional 8.2-megadalton (Md) EcoRI fragment that had the same mobility as one of the EcoRI fragments of the F', and (ii) conferred repression of capsular polysaccharide synthesis and repression of sensitivity to ultraviolet radiation in a bacterial transformation experiment with capR mutant recipient strains. A capR9 mutant plasmid, pBZ201M9, was also isolated and conferred expression of mucoidy and ultraviolet sensitivity to a capR(+) (lon(+)) strain, indicating that the capR9 allele was dominant. Plasmids pBZ201M80, pBZ201M9-INSA, and pBZ201M9-INSB were characterized by transformation as containing recessive capR mutant alleles. Heteroduplex analyses and agarose gel electrophoresis of restriction endonuclease digests of plasmid DNA preparations revealed that (i) pBZ201M9-INSA and pBZ201M9-INSB each contains a 0.5-Md insertion (probably IS1) in the cloned DNA fragment at the same site, and (ii) pBZ201 and pBZ203, both capR(+) plasmids, contain the same 8.2-Md fragment cloned in opposite orientations with respect to the cloning vehicle, pSC101. Plasmid-specified polypeptides were determined by using strain CSR603 maxicells containing each plasmid. Two new polypeptides were coded by the lon(+) (capR(+)) 8.2-Md DNA fragment: Z1, 94 kilodaltons (94K), and Z2, 67K. The maxicells containing recessive capR mutant plasmids were deficient only in synthesis of the 94K polypeptide, and the dominant (capR9) mutant plasmid specified 5 to 10 times more of the 94K polypeptide than the maxicells containing the capR(+) plasmid. Other data indicated that the capR9-specified "94K polypeptide" was not identical to the capR(+)-specified "94K polypeptide." Thus the altered mutant polypeptide was synthesized in increased quantities, suggesting a defective mode of autogenous regulation for the capR9 polypeptide and effective autogenous regulation of the capR(+) polypeptide.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
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
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
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, 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
D005144	F Factor	A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.	Resistance Transfer Factor,Sex Factor F,Sex Factor, Bacterial,Bacterial Sex Factor,Bacterial Sex Factors,F Plasmid,F Plasmids,Factor, Bacterial Sex,Factors, Bacterial Sex,Fertility Factor, Bacterial,Sex Factors, Bacterial,Bacterial Fertility Factor,Bacterial Fertility Factors,F Factors,Factor F, Sex,Factor Fs, Sex,Factor, Bacterial Fertility,Factor, F,Factor, Resistance Transfer,Factors, Bacterial Fertility,Factors, F,Factors, Resistance Transfer,Fertility Factors, Bacterial,Fs, Sex Factor,Plasmid, F,Plasmids, F,Resistance Transfer Factors,Sex Factor Fs,Transfer Factor, Resistance,Transfer Factors, Resistance
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial