Mating Type Specific Inhibition of Gametic Differentiation of Chlamydomonas reinhardtii by Tunicamycin

The effect of tunicamycin, an inhibitor of glycosylation ofproteins, on the gametic differentiation of Chlamydomonas reinhardtiiwas studied. When mt⁺ cells were treated with tunicamycin duringgametogenesis, the acquisition of agglutinability on their flagellawas completely inhibited. However, no significant inhibitionwas observed when mt^– cells were treated with tunicamycinduring gametic induction. The agglutinability of the fully competentgametes of mt⁺ cells decreased sharply after about 4 hr of incubationwith tunicamycin and was lost completely after 8 hr. These resultsindicate that the gametic flagellar membrane of the mt⁺ cellmay acquire glycoproteins with tunicamycin sensitive sugar chains,the halflife of which is about 6 hr. (Received August 11, 1981; Accepted October 7, 1981)