Characterization of a Fission Yeast SUMO-1 Homologue, Pmt3p, Required for Multiple Nuclear Events, Including the Control of Telomere Length and Chromosome Segregation
Characterization of a Fission Yeast SUMO-1 Homologue, Pmt3p, Required for Multiple Nuclear Events, Including the Control of Telomere Length and Chromosome Segregation
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DOI：
10.1128/mcb.19.12.8660
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发表时间：
1999-12
影响因子：
5.3
通讯作者：
Katsunori Tanaka;Junko Nishide;K. Okazaki;Hiroaki Kato;O. Niwa;T. Nakagawa;H. Matsuda;M. Kawamukai;Y. Murakami
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文献类型：
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作者：
Katsunori Tanaka;Junko Nishide;K. Okazaki;Hiroaki Kato;O. Niwa;T. Nakagawa;H. Matsuda;M. Kawamukai;Y. Murakami
与泛素不同，泛素样蛋白修饰物SUMO-1及其芽殖酵母同源物Smt 3 p在蛋白质翻译后修饰中的作用比蛋白质降解更重要。在这里，我们描述了识别的SUMO-1同源的裂变酵母，我们表明是需要的一些核事件，包括控制端粒长度和染色体分离。pmt 3+基因（SMT 3的粟酒裂殖酵母同源物）的破坏不是致命的，但是携带破坏基因的突变细胞生长得更慢。pmt 3 Δ细胞表现出多种表型，如异常的有丝分裂、对多种试剂的敏感性和微小染色体的高频丢失。有趣的是，我们发现pmt 3+是维持端粒长度所必需的。Pmt 3 p功能的丧失导致端粒长度显著增加。当Pmt 3 p合成恢复时，端粒逐渐变短。这是第一次证明参与的Smt 3 p/SUMO-1家族蛋白在端粒长度的维持。Pmt 3 p与绿色荧光蛋白（GFP）的融合显示Pmt 3 p主要定位于细胞核中的强斑点。其中一个斑点显示为对应于纺锤体极体（SPB）。在前中期和中期，SPB上明亮的GFP信号消失。这些观察结果表明，Pmt 3 p是所需的着丝粒和/或SPB功能参与染色体分离。这里描述的Pmt 3 p的多种功能表明，几个核蛋白的Pmt 3 p共轭调节。
ABSTRACT Unlike ubiquitin, the ubiquitin-like protein modifier SUMO-1 and its budding yeast homologue Smt3p have been shown to be more important for posttranslational protein modification than for protein degradation. Here we describe the identification of the SUMO-1 homologue of fission yeast, which we show to be required for a number of nuclear events including the control of telomere length and chromosome segregation. A disruption of thepmt3 + gene, the Schizosaccharomyces pombe homologue of SMT3, was not lethal, but mutant cells carrying the disrupted gene grew more slowly. Thepmt3Δ cells showed various phenotypes such as aberrant mitosis, sensitivity to various reagents, and high-frequency loss of minichromosomes. Interestingly, we found thatpmt3 + is required for telomere length maintenance. Loss of Pmt3p function caused a striking increase in telomere length. When Pmt3p synthesis was restored, the telomeres became gradually shorter. This is the first demonstration of involvement of one of the Smt3p/SUMO-1 family proteins in telomere length maintenance. Fusion of Pmt3p to green fluorescent protein (GFP) showed that Pmt3p was predominantly localized as intense spots in the nucleus. One of the spots was shown to correspond to the spindle pole body (SPB). During prometaphase- and metaphase, the bright GFP signals at the SPB disappeared. These observations suggest that Pmt3p is required for kinetochore and/or SPB functions involved in chromosome segregation. The multiple functions of Pmt3p described here suggest that several nuclear proteins are regulated by Pmt3p conjugation.