8-METHOXYPSORALEN PHOTOINDUCED PLASMID-CHROMOSOME RECOMBINATION IN SACCHAROMYCES-CEREVISIAE USING A CENTROMERIC VECTOR

The characterization of a new system to study the induction of plasmid -chromosome recombination is described. Single-stranded and double-str anded centromeric vectors bearing 8-methoxypsoralen photoinduced lesio ns were used to transform a wild-type yeast strain bearing the leu2-3, 112 marker. Using the SSCP methodology and DNA sequencing, it was dem onstrated that repair of the lesions in plasmid DNA was mainly due to conversion of the chromosomal allele to the plasmid DNA.