Cloning of the ribosomal protein L41 gene of Phaffia rhodozyma and its use as a drug resistance marker for transformation

The L41 protein gene of the fermenting yeast Phaffia rhodozyma was cloned and then used as a cycloheximide resistance marker during the transformation of the yeast. Transformation efficiencies of 800 to 1,200 transformants per microgram of DNA were obtained. Expression of the cycloheximide resistance gene was achieved through postincubation of electroporated cells for 14 to 16 hours. Homologous recombination into the rDNA locus appeared to be the course by which plasmid integration was accomplished in most transformants.