Reduced DNA repair during differentiation of a myogenic cell line.

摘要: Repair synthesis induced by 4-nitroquinoline-1-oxide (4NQO) in L6 myoblasts before and after cellular fusion was measured [3H] thymidine incorporation into unreplicated DNA. The level of repair reuced the cells had fused myotubes. terminal addition radioactive nucleotides DNA strands occurred only to a minor extent, dilution intracellular nucleotide pools shown not be responsible for observed difference synthesis, Both initial rate overall were found 50% lower 4NQO treatment myotubes modifications which as single-strand breaks during alkaline sucrose sedimentation. After allowed post-treatment incubation, most longer apparent. In contrast, incubation did change extent breakage seen. equally effective repairing X radiation. It would appear that when fuse, enzyme activity is lost, probably an endonuclease recognizes one 4 NQO result partial loss synthetic ability complete remove modification appears break alkali.