Plasmids with the Cre-recombinase and the dominant nat marker, suitable for use in prototrophic strains of Saccharomyces cerevisiae and Kluyveromyces lactis

Two plasmids are described which can be used to remove the 'loxP-markerMX-loxP' cassettes in strains lacking the ura3 mutation. Both contain the Cre-recombinase under control of the GAL1 promoter and the natMX cassette with the dominant marker not, which gi ces yeasts resistance to the antibiotic ClonNat. pNatCre contains ARSH and CEN6 for maintenance in Saccharomyces cerevisiae. pK1NatCre has a Kluyveromyces lactis replication origin and centromere in addition, Copyright (C) 2001 John Wiley & Sons, Ltd.