title: Control of recombination within and between DNA plasmids of Saccharomyces cerevisiae.
abstract: [2 μm(+) and [2μm°] yeast were transformed to stable leucine prototrophy with the hybrid yeast - E. coli plasmid, pJDB219. This plasmid contains the entire sequence of the endogenous 2 μm yeast DNA plasmid in addition to the yeast nuclear LEU2 (+) gene and the Co1E1 derivative, pMB9. In the [2 μm(+)] transformants, a new wholly yeast LEU2 (+) plasmid, pYX, was generated, probably by a recombination event between pJDB219 and 2 μm DNA. The plamid, pYX, in the absence of 2 μm DNA, was found to exist in equimolar amounts of two forms, A and B, which probably arise by intramolecular recombination across the inverted repeat sequences of the 2 μm DNA portion of the plasmid. pJDB219 was found to require the presence of 2 μm DNA to undergo this intramolecular recombination. The results suggest that 2, μm DNA and pYX code for a gene product required in this recombination event which pJDB219 cannot produce.
authors.affiliation: Botany School, South Parks Road, OX1 3RA, Oxford, England.
authors.forename: M J
authors.initials: MJ
authors.lastname: Dobson
authors.forename: A B
authors.initials: AB
authors.lastname: Futcher
authors.forename: B S
authors.initials: BS
authors.lastname: Cox