title: An excision event that may depend on patchy homology for site specificity.
abstract: In mouse cells transformed by a mutant polyomavirus genome, recombination between integrated viral DNA and flanking cellular DNA resulted in the excision of two readily amplifiable chimeras, designated RmI and RmII. The crossing-over that generated RmII was unique in that it involved a simple cellular sequence in which the triplet 5'-CTG-3' was repeated many times. We show that the sequence across the junction resulting from excision was identical in several molecules of RmII, as if the cross-over generating this junction always involved exactly the same two sites on the viral and cellular DNA. We also show that the cellular site mapped where the replacement of a G by an A in one of many successive 5'-CTG-3' triplets generated a homology of five nucleotides (5'-CTACT-3') with the viral site. Oligonucleotides on both sides of these sites are probably involved in matching the two DNAs prior to recombination.
mesh_terms: D000818:Animals; D002678:Chimera; D004247:DNA / Q000032:analysis; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004279:DNA, Viral / Q000032:analysis; D051379:Mice; D009154:Mutation; D011120:Polyomavirus / Q000235:genetics*; D011995:Recombination, Genetic; D013329:Structure-Activity Relationship
chemical_list: D004279:DNA, Viral; D004247:DNA; D004262:DNA Restriction Enzymes