Three new dominant drug resistance cassettes for gene disruption in Saccharomyces cerevisiae

Disruption-deletion cassettes are powerful tools used to study gene functio n in many organisms, including Saccharomyces cerevisiae. Perhaps the most w idely useful of these are the heterologous dominant drug resistance cassett es, which use antibiotic resistance genes from bacteria and fungi as select able markers. We have created three new dominant drug resistance cassettes by replacing the kanamycin resistance (kan(r)) open reading frame from the kanMX3 and kanMX4 disruption-deletion cassettes (Wach et al., 1994) with op en reading frames conferring resistance to the antibiotics hygromycin B (hp h), nourseothricin (nat) and bialaphos (pat). The new cassettes, pAG25 (nat MX4), pAG29 (patMX4), pAG31 (patMX3), pAG32 (hphMX4), pAG34 (hphMX3) and pA G35 (natMX3), are cloned into pFA6, and so are in all other respects identi cal to pFA6-kanMX3 and pFA6-kanMX4. Most tools and techniques used with the kanMX plasmids can also be used with the hph, nat and patMX containing pla smids. These new heterologous dominant drug resistance cassettes have uniqu e antibiotic resistance phenotypes and do not affect growth when inserted i nto the ho locus. These attributes make the cassettes ideally suited for cr eating S. cerevisae strains with multiple mutations within a single strain. Copyright (C) 1999 John Wiley & Sons, Ltd.