EXPRESSION OF YWP1, A GENE THAT ENCODES A SPECIFIC YARROWIA-LIPOLYTICA MYCELIAL CELL-WALL PROTEIN, IN SACCHAROMYCES-CEREVISIAE

The YWP1 gene encoding a specific mycelial cell wall protein of Yarrow ia lipolytica has been cloned and expressed in Saccharomyces cerevisia e using different episomal plasmids, Because the plasmids pYAE35BB and pYAE35ES carrying the YWP1 gene (including the 5' noncoding promoter sequences) failed to express it, the YWP1 gene was cloned under the co ntrol of GAL/CYC or ACT S. cerevisiae promoters, A main band with an a pparent molecular mass of 70 kDa was detected by immunoblotting in the cell wall fraction of transformants, Ywp1 processing and incorporatio n to the cell wall were similar in both Y. lipolytica and S. cerevisia e but not in its final localization in the cell wall. In Y. lipolytica Ywp1 is covalently bound to the cell wall (it is released only by Zym olyase digestion), whereas in S. cerevisiae it was not (it was release d by boiling SDS solutions), These results suggest that the sequences involved in recognition, anchoring of a protein to the cell wall, or t he catalytic activities implicated are different, at least for Ywp1, i n Y. lipolytica and S. cerevisiae. Another possibility is that the tar get for attachment of Ywp1 is missing or cryptic in the cell wall of S . cerevisiae. (C) 1997 Academic Press.