Genomic library of DNA from an extracellular protease-producing yeast strain, Rhodotorula glutinis K-24, was constructed, using Escherichia coli plasmid vector PBR322. A LEU gene from R. glutinis was cloned, and found to complement leu- mutations in E. coli and Saccharomyces cerevisiae. In E. coli, the LEU gene in the cloned yeast DNA fragment was efficiently expressed when inserted into the vector in one orientation. In S. cerevisiae, the R. glutinis LEU gene was efficiently expressed when inserted into a shuttle vector YEP13 in both orientations, suggesting that the isolated R. glutinis DNA fragment contains a promotor sequence of R. glutinis in front of the LEU gene. In addition, our data suggests that the cloned LEU fragment also contains an ARS (autonomously replication sequence) site of R. glutinis that could function in S. cerevisiae.