Biomaterial Database

Hyperrecombination at a specific DNA sequence in pneumococcal transformation. 1984

J C Lefèvre, and A M Gasc, and A C Burger, and P Mostachfi, and A M Sicard

In pneumococcal transformation, recombination frequency between point mutations is usually proportional to physical distances. We have identified an aberrant marker belonging to the amiA locus that appeared to markedly enhance recombination frequency when crossed with any other markers of this gene. This mutation results from the C-to-A transversion in the sequence A-T-T-C-A-T----A-T-T-A-A-T. This effect is especially apparent for short distances as small as 27 base pairs. The hyperrecombination does not require the wild-type function of the pneumococcal gene for an ATP-dependent DNase (which is homologous to the product of the Escherichia coli recBC genes) or of the hex genes, which correct certain mismatched bases in transformation. The hyperrecombination is affected by the presence of nearby mismatched bases that trigger an excision-repair system. It is proposed that the mutation that shows hyperrecombination is sometimes converted to the wild-type allele at the heteroduplex stage of transformation.

UI	MeSH Term	Description	Entries
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
D004274	DNA, Recombinant	Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.	Genes, Spliced,Recombinant DNA,Spliced Gene,Recombinant DNA Research,Recombination Joint,DNA Research, Recombinant,Gene, Spliced,Joint, Recombination,Research, Recombinant DNA,Spliced Genes
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
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
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D013296	Streptococcus pneumoniae	A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.	Diplococcus pneumoniae,Pneumococcus
D014169	Transformation, Bacterial	The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.	Bacterial Transformation