The endo-β-1,3-glucanase eng1p is required for dissolution of the primary septum during cell separation in Schizosaccharomyces pombe
The endo-β-1,3-glucanase eng1p is required for dissolution of the primary septum during cell separation in Schizosaccharomyces pombe
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DOI：
10.1242/jcs.00377
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发表时间：
2003-05-01
影响因子：
4
通讯作者：
del Rey, F
中科院分区：
文献类型：
--
作者：
Martín-Cuadrado, AB;Dueñas, E;del Rey, F
粟酒裂殖酵母细胞分裂的中间分裂整个收缩的肌动球蛋白环和沉积的多层分裂隔膜，必须裂解释放两个子细胞。虽然许多研究都集中在actomyosin环和隔膜组件，很少有信息是关于细胞分离的机制。在这里，我们描述了eng 1（+），一个新的基因，编码一种蛋白质与可检测的内切β-1，3-葡聚糖酶的活性，其删除是不是致命的细胞，但在他们的分离干扰的表征。对突变细胞的电子显微镜观察表明，这种缺陷主要是由于细胞未能降解分隔两个姐妹篇细胞的初级隔膜，初级隔膜是一种富含β-1，3-葡聚糖的结构。eng 1（+）的表达在细胞周期中变化，在分隔前观察到最大表达，并且蛋白质在细胞分离期间定位于围绕分隔区域的环状结构。这表明它也可能参与了覆盖分裂隔膜的细胞壁圆柱体的分裂。eng 1（+）在营养生长过程中的表达受C2 H2锌指蛋白（由SPAC6G10.12c ORF编码）的调节，该蛋白与酿酒酵母ScAce 2 p显示出显著的序列相似性，特别是在锌指区域。缺乏这种转录调节因子的突变体（我们命名为ace 2（+））表现出严重的细胞分离缺陷，观察到菌丝生长。因此，ace 2 p可能调节eng 1（+）基因的表达，以及其他基因的表达，这些基因的产物也参与细胞分离。
Schizosaccharomyces pombe cells divide by medial fission throughout contraction of an actomyosin ring and deposition of a multilayered division septum that must be cleaved to release the two daughter cells. Although many studies have focused on the actomoysin ring and septum assembly, little information is available concerning the mechanism of cell separation. Here we describe the characterization of eng1(+), a new gene that encodes a protein with detectable endo-beta-1,3-glucanase activity and whose deletion is not lethal to the cells but does interfere in their separation. Electron microscopic observation of mutant cells indicated that this defect is mainly due to the failure of the cells to degrade the primary septum, a structure rich in beta-1,3-glucans, that separates the two sisters cells. Expression of eng1(+) varies during the cell cycle, maximum expression being observed before septation, and the protein localizes to a ring-like structure that surrounds the septum region during cell separation. This suggests that it could also be involved in the cleavage of the cylinder of the cell wall that covers the division septum. The expression of eng1(+) during vegetative growth is regulated by a C2H2 zinc-finger protein (encoded by the SPAC6G10.12c ORF), which shows significant sequence similarity to the Saccharomyces cerevisiae ScAce2p, especially in the zinc-finger region. Mutants lacking this transcriptional regulator (which we have named ace2(+)) show a severe cell separation defect, hyphal growth being observed. Thus, ace2p may regulate the expression of the eng1(+) gene together with that of other genes whose products are also involved in cell separation.