A NOVEL CELL-WALL PROTEIN-SPECIFIC TO THE MYCELIAL FORM OF YARROWIA-LIPOLYTICA

A cDNA clone specifying a cell wall protein was isolated from a Yarrow ia lipolytica cDNA library. The cDNA library was constructed in the ex pression vector lambda gt11, with the RNA isolated from actively growi ng mycelial cells. The deduced amino acid sequence shows that the enco ded protein contains an N-terminal hydrophobic signal peptide. We have designated this protein YWP1 for (Y) under bar arrowia lipolytica cel l (W) under bar all (P) under bar rotein. Northern hybridization ident ified YWP1 transcript only when Y. lipolytica was growing in the mycel ial form. The encoded protein seems to be covalently bound to the gluc an cell wall since it is not released from the cell walls by sodium do decyl sulphate extraction, but it is solubilized following partial deg radation of beta-glucan by Zymolyase digestion. The protein is localiz ed in the outer surface on the tip of the growing mycelial cells and i s found partially cryptic in sub-apical locations, suggesting that it participates directly in the mycelial wall architecture.