[Role of the product of recB-gene in the thymine-less death and characteristics of this phenomenon in a thy-recB--mutant of Escherichia coli K-12].
Thymine requiring mutants of rec+ and recB- Escherichia coli strains have been tested for their response to thymine deprivation. Exonuclease V-deficient mutant is less sensitive to thymine deprivation than the wild type strain, because there is no lag period at thymineless death of recB- thy- cells. However, the mechanism of thymineless death of thy- rec+ and thy- recB- cells may be different. Two types of thymineless death are proposed to exist. The first type is due to DNA primary structure damages (single-strand breaks or gaps), accompanied by DNA degradation. The restoration of the balance disturbed by the thymine deprivation between DNA and protein synthesis rates by their balanced inhibition promotes a complete repair of structural damages in DNA and prevents the death of rec+ cells. The second type of thymineless death is not linked with the formation of DNA damages, and this is observed in recB- thy- mutant, defective in exonuclease V.
D001426:Bacterial Proteins / Q000096:biosynthesis*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005092:Exonucleases / Q000502:physiology; D009154:Mutation; D013941:Thymine
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005092:Exonucleases; D013941:Thymine
Rol' produkta recB-gena v bestiminovoĭ gibeli i osobenmosti étogo fenomena u thy-recB--mutanta Escherichia coli K-12.