Hünseler P, Scheidgen-Kleyboldt G, Tiedtke A
Institute of Zoology, University of Münster, FRG.
J Cell Sci. 1987 Aug;88 ( Pt 1):47-55. doi: 10.1242/jcs.88.1.47.
The development of a sensitive screening procedure for mutants of Tetrahymena thermophila blocked in secretion of lysosomal enzymes is described. By means of this procedure a mutant blocked in secretion of lysosomal enzymes has been isolated. This sec- mutant, MS-1, is constitutively blocked in release of at least six lysosomal enzymes, under both nutrient and non-nutrient conditions. MS-1 possesses, bound within the cell, the same amount of active lysosomal enzymes as the wild type. During starvation in media of low ionic strength MS-1 develops a highly vacuolated phenotype. This phenotype is caused by the sec- allele. It is reversed to a normal cell shape when the mutant is transferred to isotonic medium. The sec- mutant MS-1 contains mucocysts and is capable of inducing exocytosis of these secretory organelles, suggesting that Tetrahymena possesses at least two independent protein-secreting organelles.
本文描述了一种用于筛选嗜热四膜虫溶酶体酶分泌受阻突变体的灵敏筛选方法。通过该方法，已分离出一种溶酶体酶分泌受阻的突变体。这种sec-突变体MS-1在营养和非营养条件下，至少六种溶酶体酶的释放均持续受阻。MS-1细胞内结合的活性溶酶体酶量与野生型相同。在低离子强度培养基中饥饿时，MS-1会出现高度空泡化的表型。这种表型是由sec-等位基因引起的。当将该突变体转移到等渗培养基中时，其表型会恢复为正常细胞形状。sec-突变体MS-1含有黏液泡，并且能够诱导这些分泌细胞器的胞吐作用，这表明嗜热四膜虫至少拥有两种独立的蛋白质分泌细胞器。
