Necas O, Svoboda A
Eur J Cell Biol. 1986 Aug;41(2):165-73.
Permissive and restrictive phenotypes of two secretory mutants of Saccharomyces cerevisiae, sec 1 and sec 18, were studied by freeze-fracture technique. The sec 1 mutant, in addition to accumulating secretory vesicles, was characterized by a disappearance of the plasma membrane invaginations and by an aggregation of intra-membrane particles in vacuolar membranes. A prolonged incubation of the cells at 37 degrees C led to pathological fusion of some vesicles with the plasma membrane. After the cells were transferred back to the permissive temperature the invaginations reappeared rapidly while the accumulated vesicles disappeared only after budding had been resumed. The sec 18 mutant, apart from having distended endoplasmic reticulum membranes, also lost the plasma membrane invaginations at 37 degrees C and regained them at 24 degrees C. The described ultrastructural changes are typical for the restrictive phenotypes and represent further manifestations of the pleiotropic effect of the respective sec mutations.
通过冷冻断裂技术研究了酿酒酵母的两个分泌突变体sec 1和sec 18的允许型和限制型表型。sec 1突变体除了积累分泌囊泡外，其特征还在于质膜内陷消失以及液泡膜内颗粒聚集。细胞在37℃长时间孵育导致一些囊泡与质膜发生病理性融合。当细胞转移回允许温度后，内陷迅速重新出现，而积累的囊泡仅在恢复出芽后才消失。sec 18突变体除了具有扩张的内质网膜外，在37℃时也失去了质膜内陷，并在24℃时重新获得。所描述的超微结构变化是限制型表型的典型特征，代表了相应sec突变多效性效应的进一步表现。
