title: SV40 deletion mutants lacking the 21-bp repeated sequences are viable, but have noncomplementable deficiencies.
abstract: We have constructed deletion mutants of simian virus 40 (SV40) lacking the two tandemly repeated copies or all three copies of the 21-bp repeated sequence located in the origin region. The mutants were viable, but had lower infectivities compared to the wild type. The mutant lacking two copies of the 21-bp repeat grew fairly well indicating that the one copy of the 21-bp repeat it contains is adequate. The other mutant lacking all the three copies of the 21-bp repeat was also viable but grew poorly. The viability of this mutant suggests that the upstream 72-bp repeated sequence compensates, though only partially, for the absence of the 21-bp repeat. The growth deficiencies of the deletion mutants could not be overcome by complementation with temperature-sensitive helper mutants providing either the early or the late functions of the virus, suggesting that the deficiencies lie in both early and late gene expression and/or in replication.
mesh_terms: D000818:Animals; D001482:Base Composition; D002460:Cell Line; D002522:Chlorocebus aethiops; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics*; D007668:Kidney; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D013539:Simian virus 40 / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D004262:DNA Restriction Enzymes