The fission yeast Schizosaccharomyces pombe has two distinct tRNase ZLs encoded by two different genes and differentially targeted to the nucleus and mitochondria
The fission yeast Schizosaccharomyces pombe has two distinct tRNase ZLs encoded by two different genes and differentially targeted to the nucleus and mitochondria
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裂殖酵母粟酒裂殖酵母有两种不同的 tRNase ZL，由两个不同的基因编码，并分别靶向细胞核和线粒体
DOI：
10.1042/bj20101619
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发表时间：
2011-04-01
影响因子：
4.1
通讯作者：
Huang, Ying
中科院分区：
文献类型：
--
作者：
Gan, Xuhua;Yang, Jing;Huang, Ying
tRNase Z 是一种核酸内切酶，通过从 tRNA 前体中去除 3' 尾序列来参与 tRNA 3' 末端成熟。迄今为止检查的大多数真核生物，包括芽殖酵母酿酒酵母和人类，都具有单一长形式的 tRNase Z (tRNase Z(L))。相比之下，裂殖酵母裂殖酵母含有两个候选 tRNase Z(L)，由必需基因 sptrz1(+) 和 sptrz2(+) 编码。在本研究中，我们在粟酒裂殖酵母中表达了重组 SpTrz1p 和 SpTrz2p。两种重组蛋白均具有体外前体 tRNA 3'-核酸内切活性。 SpTrz1p定位于细胞核，并在其N末端具有类似猿猴病毒40 NLS（核定位信号）的NLS，其在残基208和211之间包含对于NLS功能至关重要的四个连续的精氨酸和赖氨酸残基。相比之下，SpTrz2p 是一种具有 N 末端 MTS（线粒体靶向信号）的线粒体蛋白。 sptrz1(+) 的高水平过度表达没有可检测到的表型。相比之下，sptrz2(+)的强烈过度表达在野生型细胞中是致命的，并导致形态异常，包括细胞肿胀和圆形，这表明sptrz2(+)的正确表达水平至关重要。本研究为粟酒裂殖酵母中两种不同蛋白质之间 tRNase Z 功能的划分提供了证据，尽管我们不能排除每种蛋白质的特殊功能。
tRNase Z is the endonuclease that is involved in tRNA 3'-end maturation by removal of the 3'-trailer sequences from tRNA precursors. Most eukaryotes examined to date, including the budding yeast Saccharomyces cerevisiae and humans, have a single long form of tRNase Z (tRNase Z(L)). In contrast, the fission yeast Schizosaccharomyces pombe contains two candidate tRNase Z(L)s encoded by the essential genes sptrz1(+) and sptrz2(+). In the present study, we have expressed recombinant SpTrz1p and SpTrz2p in S. pombe. Both recombinant proteins possess precursor tRNA 3'-endonucleolytic activity in vitro. SpTrz1p localizes to the nucleus and has a simian virus 40 NLS (nuclear localization signal)-like NLS at its N-terminus, which contains four consecutive arginine and lysine residues between residues 208 and 211 that are critical for the NLS function. In contrast, SpTrz2p is a mitochondrial protein with an N-terminal MTS (mitochondrial-targeting signal). High-level overexpression of sptrz1(+) has no detectable phenotypes. In contrast, strong overexpression of sptrz2(+) is lethal in wild-type cells and results in morphological abnormalities, including swollen and round cells, demonstrating that the correct expression level of sptrz2(+) is critical. The present study provides evidence for partitioning of tRNase Z function between two different proteins in S. pombe, although we cannot rule out specialized functions for each protein.