Ribosomal DNA plasmid isolated from Zygosaccharomyces bailii and its use for constructing yeast vectors effective for intergeneric gene transfer.

Abstract

A part of the rDNA plasmid of Zygosaccharomyces bailii IFO 0488 has been cloned. The cloned sequence contained 18S, 25S and probably 5S rRNA sequences. The cloned rDNA of Z. bailii hybridized with rRNAs of Saccharomyces cerevisiae. On using this rDNA sequence as a probe, we found that every sample of closed circular DNA from yeasts tested contained this kind of DNA plasmid. The rDNA unit from Z. bailii carried an ARS that functioned in S. cerevisiae and Z. rouxii. However, the sequence required for the ARS function differed depending on the host. When a vector based on the rDNA of Z. bailii was introduced into S. cerevisiae, it was integrated predominantly into the RDNl locus. These facts imply that the rDNA plasmid is practically useful for contructing vectors suitable for intergeneric gene transfer among yeasts.