Tunicamycin-sensitive glycoproteins involved in the mating of Chlamydomonas reinhardi

It has been previously shown that mild trypsinization of Chlamydomonas gametes reversibly inhibits steps of the mating process. Gametic agglutination is delayed 30–60 min, while cell wall hydrolysis and zygote formation are delayed 1–3 h. If gametes are pretreated with 5 μg/ml tunicamycin (TM) for 1 h and then trypsinized, the recovery of agglutination is blocked. These results indicate that N-glycosylated glycoproteins are involved in agglutination. Treatment of normal gametes with tunicamycin alone does not have a significant effect on agglutination and mating efficiency, suggesting that there is little or no turnover of the surface receptors before mating. Tunicamycin also interferes with cell growth and prevents the conversion of vegetative cells into gametes.