The fission yeast MTREC and EJC orthologs ensure the maturation of meiotic transcripts during meiosis.
The fission yeast MTREC and EJC orthologs ensure the maturation of meiotic transcripts during meiosis.
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DOI：
10.1261/rna.055608.115
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
Zhang K
中科院分区：
文献类型：
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作者：
Marayati BF;Hoskins V;Boger RW;Tucker JF;Fishman ES;Bray AS;Zhang K
减数分裂是一个高度调节的过程，遗传信息通过有性生殖传递。它包括在营养细胞中不发生的独特机制，产生独特的，调节良好的减数分裂转录组。在营养生长过程中，许多减数分裂基因组成型转录，但大多数产生的mRNA被Mmi 1-MTREC（Mtl 1-Red 1核心）复合物迅速消除。虽然Mmi 1-MTREC靶向未成熟的减数分裂RNA，在有丝分裂生长期间被核3′-5′核糖核酸外切酶外切体降解，但其在减数分裂期间减数分裂基因表达中的作用尚不清楚。在这里，我们报告，Red 5，一个必不可少的MTREC组件，与pFal 1，在裂殖酵母裂殖酵母中的真核翻译起始因子eIF 4aIII的直系同源物相互作用。在哺乳动物中，与MAGO（Mnh 1）、Rnps 1和Y14一起，eIF 4AIII（pFal 1）形成外显子连接复合物（EJC）的核心，其对于成熟mRNA的转录监视和定位是必需的。在裂殖酵母中，两个EJC直系同源物pFal 1和Mnh 1与MTREC功能相关，特别是在减数分裂期间的减数分裂基因表达过程中。虽然pFal 1与Mnh 1、Y14和Rnps 1相互作用，但其与Mnh 1的结合在Y14或Rnps 1丢失后不被破坏。Red 1、Red 5、pFal 1或Mnh 1的突变产生严重的减数分裂缺陷;减数分裂期间减数分裂转录物的丰度降低; mRNA成熟过程如剪接受损。由于研究哺乳动物生殖细胞减数分裂是困难的，我们在裂殖酵母中的发现可能有助于确定高等真核生物中精确减数分裂基因表达的一般机制。
Meiosis is a highly regulated process by which genetic information is transmitted through sexual reproduction. It encompasses unique mechanisms that do not occur in vegetative cells, producing a distinct, well-regulated meiotic transcriptome. During vegetative growth, many meiotic genes are constitutively transcribed, but most of the resulting mRNAs are rapidly eliminated by the Mmi1-MTREC (Mtl1-Red1 core) complex. While Mmi1-MTREC targets premature meiotic RNAs for degradation by the nuclear 3′–5′ exoribonuclease exosome during mitotic growth, its role in meiotic gene expression during meiosis is not known. Here, we report that Red5, an essential MTREC component, interacts with pFal1, an ortholog of eukaryotic translation initiation factor eIF4aIII in the fission yeast Schizosaccharomyces pombe. In mammals, together with MAGO (Mnh1), Rnps1, and Y14, elF4AIII (pFal1) forms the core of the exon junction complex (EJC), which is essential for transcriptional surveillance and localization of mature mRNAs. In fission yeast, two EJC orthologs, pFal1 and Mnh1, are functionally connected with MTREC, specifically in the process of meiotic gene expression during meiosis. Although pFal1 interacts with Mnh1, Y14, and Rnps1, its association with Mnh1 is not disrupted upon loss of Y14 or Rnps1. Mutations of Red1, Red5, pFal1, or Mnh1 produce severe meiotic defects; the abundance of meiotic transcripts during meiosis decreases; and mRNA maturation processes such as splicing are impaired. Since studying meiosis in mammalian germline cells is difficult, our findings in fission yeast may help to define the general mechanisms involved in accurate meiotic gene expression in higher eukaryotes.