Identification of mammalian DNA repair factors using a reconstituted subcellular system. Partial characterization and subcellular location of a DNA repair-stimulating protein in hamster cells.
By reconstituting lysolecithin-permeabilized hamster cells with endogenous proteins, a protein(s) which stimulated bleomycin-induced DNA repair synthesis was identified. The repair protein was inactivated by proteinase K and had an apparent molecular weight of 12 000-15 000 D. The following enzymatic activities were not detected in the partially purified DNA repair protein: general endonuclease, apurinic endonuclease, exonuclease, DNA polymerase or DNA polymerase beta-stimulating activity. The subcellular location of the DNA repair-stimulating activity was investigated by cytochalasin B enucleation; approx. 80% of the activity was associated with karyoplasts, suggesting a nuclear location. Neither the activity nor subcellular location of the repair protein fluctuated appreciably during the cell cycle, consistent with a physiological role in DNA repair. Although the function of the DNA repair protein is not yet known, this approach should be useful in identifying and characterizing mammalian DNA repair proteins.
D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000032:analysis*; D006224:Cricetinae; D004260:DNA Repair; D005260:Female; D007399:Interphase; D008970:Molecular Weight; D010053:Ovary; D011506:Proteins / Q000032:analysis* / Q000302:isolation & purification / Q000502:physiology
D011506:Proteins