title: DNA sequences required to induce localized conversion in Streptococcus pneumoniae transformation.
abstract: In pneumococcal transformation a particular point mutation belonging to the amiA locus is able markedly to enhance recombination frequency when crossed with any other markers of this gene. This results from a polarized conversion of the mutation towards the wild-type sequence. In this report, by site-directed oligonucleotide mutagenesis, we have generated a series of mutants showing various degrees of conversion. We have found that the substitution 5'-ATTCAT----5'-ATTAAT is a sufficient signal for localized conversion. Changing individual bases within this sequence results in decreased conversion frequencies to levels that depend on the mutation, suggesting that there is a family to related sequences which may act as a substrate for a conversion system. Moreover, the length over which this conversion occurs has been estimated to be 12 base pairs on the average.
authors.affiliation: Centre de Recherche de Biochimie et Génétique Cellulaires du C.N.R.S., Toulouse, France.
authors.forename: P
authors.initials: P
authors.lastname: Garcia
authors.forename: A M
authors.initials: AM
authors.lastname: Gasc
authors.forename: X
authors.initials: X
authors.lastname: Kyriakidis
authors.forename: D
authors.initials: D
authors.lastname: Baty
authors.forename: M
authors.initials: M
authors.lastname: Sicard
mesh_terms: D001483:Base Sequence; D004260:DNA Repair; D004269:DNA, Bacterial / Q000187:drug effects; D005785:Gene Conversion / Q000187:drug effects; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009153:Mutagens; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D013296:Streptococcus pneumoniae / Q000235:genetics*; D014170:Transformation, Genetic / Q000187:drug effects
chemical_list: D004269:DNA, Bacterial; D009153:Mutagens; D009841:Oligonucleotides