Characterization of yeast mutant #64: occurrence of shorter-chain C 55–60 polyprenol

Abstract

To understand the dolichol biosynthetic pathway in detail, we performed complementation analysis of the yeast temperature-sensitive mutant #64 that exhibits defects in protein glycosylation with a reduced pool of endogenous dolichyl phosphate. Three transformants (#64-1, #64-2, and #64-4) were isolated and analyzed for possession of a fragment of chromosome IV, XIII, and VII, respectively. Endogenous dolichyl-P content of the wild type, #64, #64-1, #64-2, and #64-4 was 10.0, 2.2, 3.4, 3.0, and 1.8 μg/10 10 cells, respectively. In the case of endogenous dolichol, the content was 2.4, 3.8, 4.0, 0.8, and 3.2 μg/10 10 cells, respectively. Shorter-chain (C 55–C 60) polyprenol (dehydrodolichol) was also detected in mutant #64 (1.0 μg/10 10 cells), #64-1 (1.5 μg/10 10 cells), and #64-2 (1.9 μg/10 10 cells), but not in #64-4 and the wild type. These facts imply that not only dolichyl-P, but also unknown shorter-chain polyprenyl-derived compounds, play the important role in dolichol biosynthesis.