Integration of heterologous genes into the chromosome of Saccharomyces cerevisiae using a delta sequence of yeast retrotransposon Ty

Summary Distribution of a delta () sequence of the Ty element on a chromosome of the yeast Saccharomyces cerevisiae was analysed by pulsed-field gel electrophoresis. More than 100 copies of the sequence were non-randomly distributed on the chromosome. Using the sequence as a recombination site, mouse -amylase and human -endorphin genes were introduced into the chromosomal DNA. The integration occurred on a particular chromosome in each case and the copy number was estimated as three to five. It was also found that single- or multi-copy integration occured at a single or multiple sites on the particular chromosome. The integrants secreted -amylase and -endorphin by three-to fivefold compared with single-copy integrants. This type of integration was mitotically stable over a period of 50 generations under non-selective conditions.Offprint requests to: A. Sakai