Processive nicking activity of T4 endonuclease V on UV-irradiated chromatin
T4 endonuclease V initiates the excision repair of pyrimidine dimers in UV-irradiated T4 infected E. coli cells. The pyrimidine dimer specific nicking activity of T4 endonuclease V functions by a processive scanning on UV-irradiated DNA. Previously it has been demonstrated that introduction of endonuclease V into repair-deficient human cells causes a restoration of UV survival in these cells. This demonstrates that endonuclease V is competent to incise mammalian DNA at the site of pyrimidine dimers. In order to assess the ability of endonuclease V to act processively on DNA associated as chromatin, minichromosomes were prepared for use as a substrate. Form I DNA was reconstituted with H3, H4 +/- H1 histones by sequential dialysis steps from 2.0 M NaCl to 50 mM NaCl. Time course reactions were performed with minichromosomes containing 10 and 25 dimers per molecule. In each case the rate of disappearance of form I DNA which was associated as chromatin was decreased relative to that of naked form I DNA. Concurrent with that observation, the rate and extent of appearance of form III DNA was increased with the DNA in minichromosomes relative to naked DNA. This is diagnostic of an enhancement of processivity. The inclusion of H1 in the minichromosomes resulted in a slight additional increase in processivity relative to minichromosomes consisting only of H3 and H4.
- Research Organization:
- Vanderbilt Univ., Nashville, TN
- OSTI ID:
- 6989876
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMATIN
IRRADIATION
ENDONUCLEASES
ENZYME ACTIVITY
PYRIMIDINE DIMERS
DNA REPAIR
BACTERIOPHAGES
CHROMOSOMES
DNA
ESCHERICHIA COLI
HISTONES
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA-ASE
ELECTROMAGNETIC RADIATION
ENZYMES
ESTERASES
HYDROLASES
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOPROTEINS
ORGANIC COMPOUNDS
PARASITES
PHOSPHODIESTERASES
PROTEINS
RADIATIONS
RECOVERY
REPAIR
VIRUSES
560130* - Radiation Effects on Microorganisms