Nucleic Acids Research, 1988, Vol. 16, No. 15 7499-7511
© 1988
Articles |
A novel yeast secretion signal isolated from 28K killer precursor protein encoded on the linear DNA plasmid pGKL1
Mitsubishi-Kasei Institute of Life Sciences 11 Minamiooya, Machida, Tokyo 194, Japan
*To whom correspondence should be addressed
Received March 31, 1988. Revised July 4, 1988. Accepted July 4, 1988.
Saccharomyces cerevisiae harboring linear dsDNA plasmids, pGKL1 and pGKL2, secretes a killer toxin consisting of 97, 31 and 28 kilodalton subunits (Nucleic Acids Res., 15, 1031–1046, 1987). We isolated the DNA encoding the N-terminal pre-sequence of the 28K precursor protein and constructed a new secretion vector in S. cerevisiae. Mouse 
-amylase fused to the 28K signal sequence was secreted into the culture medium with a high efficiency similar to those fused to the mating factor and 97K–31K killer signal sequences. This data clearly indicates that 28K pre-sequence functions as a secretion signal. Glycosylated and non-glycosylated -amylase molecules were detected in the culture medium. The secretion of -amylase was blocked by sec18–1 mutation. The secreted -amylase recovered from the medium was found to migrate faster in SDS-polyacrylamide gel than the precursor form of -amylase synthesized in vitro. These lines of evidence suggest that mouse -amylase fused to 28K killer signal sequence was processed, glycosylated and secreted through the normal secretion pathway of the yeast.