A gene from S. pombe with homology to E. coli RNAse III blocks conjugation and sporulation when overexpressed in wild type cells.
A gene from S. pombe with homology to E. coli RNAse III blocks conjugation and sporulation when overexpressed in wild type cells.
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与大肠杆菌 RNAse III 同源的粟酒裂殖酵母基因在野生型细胞中过表达时会阻止接合和孢子形成。
DOI：
10.1093/nar/18.17.5304
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发表时间：
1990
影响因子：
14.9
通讯作者：
Michael Wigler
中科院分区：
文献类型：
--
作者：
Hao;Michael Riggs;Linda Rodgers;Michael Wigler
我们筛选了粟酒裂殖酵母酵母中能够抑制接合和孢子形成的基因，这两种反应是饥饿引起的。单倍体菌株 Sp870 (leul-ura4-) 用克隆到 pWH5 的基因组 DNA 的 Hind HI 部分消化片段进行转化，pWH5 是表达酿酒酵母 LEU2 基因的高拷贝穿梭载体 (1)。用碘蒸气对 1.5 x104 Leu+ 转化体菌落进行染色，以鉴定不含孢子的菌落 (2)。从这些菌落中回收质粒并重新测试。因此，我们鉴定了三个相同的克隆，它们在重新转化为Sp870后能够有效抑制接合和孢子形成。含有该质粒的野生型单倍体细胞具有正常的生长速度和形态。删除分析表明，这些生物效应是由于单个开放阅读框的表达所致，如图1所示，该开放阅读框能够编码363个氨基酸的蛋白质。帧中的第一个和最后一个终止密码子以粗体表示。我们将此基因称为 hcs，表示高拷贝不育。计算机分析显示 hcs 蛋白与大肠杆菌 RNAse III 之间有 24% 的同一性（见图 2），包括 11 个氨基酸的相同区域。 RNAse III 与大肠杆菌中核糖体 RNA 的成熟有关，但也可能具有其他功能 (3,4,5)。我们推测 hcs 编码一种核糖核酸酶，该酶选择性地降解编码粟酒裂殖酵母接合和孢子形成所必需的蛋白质的 mRNA。因此，hcs 活性的调节可能是导致接合和孢子形成的信号转导事件之一。类似的RNA酶可能存在于高等生物体中，协调调节参与分化的基因的表达。东京大学的 M. Yamamoto 及其同事也鉴定出具有相同编码潜力的粟酒裂殖酵母基因（个人通讯）。
We have screened the yeast S. pombe for genes capable of inhibiting conjugation and sporulation, two responses elicited by starvation. Haploid strain Sp870 (leul-ura4-) was transformed with Hind HI partial digestion fragments ofgenomic DNA cloned into pWH5, a high copy shuttle vector expressing the S. cerevisiae LEU2 gene (1). 1.5 x104 Leu+ transformant colonies were stained with iodine vapor to identify colonies which did not contain spores (2). Plasmids were recovered from these colonies and retested. We thus identifiedthree identical clones capable of efficiently inhibiting conjugation and spore formation upon retransformation into Sp870. Wildtype haploid cells containing this plasmid have normal growth rate and morphology. Deletion analysis indicatedthat these biological effects are due to the expression of a single open reading frame, shown in Figure 1, capable of encoding a 363 amino acid protein. The first and last in frame stop codons are indicated in bold. We call this gene hcs for high copy sterile. Computer analysis revealed 24% identity between hcs protein and E. coli RNAse III (see Figure 2), including an identical region of eleven amino acids. RNAse III has beeen implicated in the maturation of ribosomal RNA in E. coli, but may have other functions as well (3, 4, 5). We speculate that hcs encodes a ribonuclease, that selectively degrades mRNAs encoding proteins essential for conjugation and sporulation in S. pombe. Regulation of the activity of hcs may thus be one of the signal transduction events leading to conjugation and sporulation. Possibly similar RNAse might exist in higher organisms that coordinately regulate the expression of genes involved in differentiation. An S. pombe gene with identical coding potential hasalso been identified by M. Yamamotoand coworkers, University of Tokyo (personal communication).