Ama1p is a meiosis-specific regulator of the anaphase promoting complex/cyclosome in yeast
Ama1p is a meiosis-specific regulator of the anaphase promoting complex/cyclosome in yeast
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DOI：
10.1073/pnas.250351297
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发表时间：
2000-12-19
影响因子：
11.1
通讯作者：
Strich, R
中科院分区：
文献类型：
--
作者：
Cooper, KF;Mallory, MJ;Strich, R
减数分裂是二倍体生物产生能够有性繁殖的单倍体配子的发育过程。在这里，我们描述了酵母基因AMA1，这是Cdc20蛋白家族的一个新成员，它调节被称为后期促进复合体/环体（APC/C）的多亚基泛素连接酶。AMA1受发育调控，其转录和剪接仅发生在减数分裂细胞中。AMA1 mRNA的减数分裂特异性加工依赖于先前描述的MER1剪接因子。结果表明，在减数分裂过程中，APC/C功能需要Ama1p。首先，共免疫沉淀实验表明Ama1p与体内APC/C相关。其次，Ama1p是降解b型细胞周期蛋白Clb1p所必需的，Clb1p是减数分裂细胞和有丝分裂细胞中的APC/C底物。第三，AMA1的异位过表达能够刺激Clb1p在体外的泛素化和Clb1p在体内的降解。缺乏AMA1的突变体表明，它是第一次减数分裂所必需的，而不是有丝分裂样减数分裂II。此外，ama 7突变体在孢子壁组装和后期减数分裂基因的表达方面都存在缺陷。总之，本研究表明Ama1p指导减数分裂APC/C仅在有丝分裂细胞分裂外起作用。APC/C-Ama1仅在减数分裂I和孢子形态发生中需要，这表明APC/C-Ama1的功能专门适应生殖细胞发育。
Meiosis is the developmental program by which diploid organisms produce haploid gametes capable of sexual reproduction. Here we describe the yeast gene AMA1, a new member of the Cdc20 protein family that regulates the multisubunit ubiquitin ligase termed the anaphase promoting complex/cyclosome (APC/C). AMA1 is developmentally regulated in that its transcription and splicing occur only in meiotic cells. The meiosis-specific processing of AMA1 mRNA depends on the previously described MER1 splicing factor. Several results indicate that Ama1p is required for APC/C function during meiosis. First, coimmunoprecipitation assays indicate that Ama1p associates with the APC/C in vivo. Second, Ama1p is required for the degradation of the B-type cyclin Clb1p, an APC/C substrate in both meiotic and mitotic cells. Third, ectopic overexpression of AMA1 is able to stimulate ubiquitination of Clb1p in vitro and degradation of Clb1p in vive. Mutants lacking AMA1 revealed that it is required for the first meiotic division but not the mitotic-like meiosis II. In addition, ama 7 mutants are defective for both spore wall assembly and the expression of late meiotic genes. In conclusion, this study indicates that Ama1p directs a meiotic APC/C that functions solely outside mitotic cell division. The requirement of Ama1p only for meiosis I and spore morphogenesis suggests a function for APC/C-Ama1 specifically adapted to germ cell development.