In vivo mechanism of UVRABC-initiated and T4 endonuclease V-initiated DNA excision repair
Various E. coli repair mutants were transformed with plasmids containing the denV gene cloned in the sense or antisense orientation relative to a prokaryotic promoter. Analyses of time course plasmid isolates from UV-irradiated uvrA/sup -/ recA/sup -/ denV/sup -/ E. coli revealed that no repair had occurred. In the case of time course repair in uvrA/sup -/ recA/sup -/ denV/sup +/ E. coli, the intensity at the position of the form I DNA at the early time points diminishes with the concomitant increase in intensity at the position of the form II DNA. At later time points intensity at the position of the form I DNA increases and a ladder of topological plasmid DNA forms is visible. Analyses of the plasmid isolates after endonuclease V treatment in vitro, show that the intensity at the position of form I DNA increases with time which indicates the accumulation of completely repaired form I DNA. This increase is linear with time suggesting that endonuclease V acts processively in vivo. Time course repair of UV-irradiated uvr/sup +/ recA/sup -/ denV/sup -/ E. coli shows that the plasmid isolates exhibit no change in the intensity at the positions of form I or II DNA throughout the time course. In addition there is no visible ladder of plasmid topological forms. However, completely repaired form I DNA accumulates with time. One possible explanation for these results is that repair, as initiated by UVRABC, proceeds to completion without a loss of superhelicity. The increase in fully repaired plasmid DNAs also increases linearly with time, suggesting processive repair.
- Research Organization:
- Vanderbilt Univ., Nashville, TN
- OSTI ID:
- 6176499
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ENDONUCLEASES
ENZYME ACTIVITY
ESCHERICHIA COLI
DNA REPAIR
GENETIC RADIATION EFFECTS
DNA
GENES
IN VIVO
PLASMIDS
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CONSTITUENTS
DNA-ASE
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERASES
GENETIC EFFECTS
HYDROLASES
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
560130* - Radiation Effects on Microorganisms