title: Reversion of a simian virus 40 enhancer mutant depends on the growth conditions.
abstract: The simian virus 40 (SV40) enhancer contains three 8-bp purine-pyrimidine (R:Y) alternating sequences (Z-motifs) which are known to adopt the left-handed Z-DNA conformation in vitro. Mutations at these three Z-motifs seriously impair enhancer function. Reversion of one of these mutants (dpm12) is studied in this paper. The results indicate that, depending on growth conditions, recovery of the enhancer function is achieved through different mechanisms. Mutant viruses growing in solid-agar medium do not revert. On the other hand, revertants obtained in liquid medium contain a duplication of the enhancer sequences, showing no recovery of the original Z-motifs.
authors.affiliation: Department of Molecular and Cellular Biology, Centro de Investigación y Desarrollo-CSIC, Barcelona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Martínez-Balbás
mesh_terms: D001483:Base Sequence; D002478:Cells, Cultured; D003470:Culture Media; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005814:Genes, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D013539:Simian virus 40 / Q000235:genetics* / Q000254:growth & development; D014162:Transfection
chemical_list: D003470:Culture Media