Li Lihong, Lu Yong, Qin Li-Xuan, Bar-Joseph Ziv, Werner-Washburne Margaret, Breeden Linda L
Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA.
Mol Biol Cell. 2009 Sep;20(17):3851-64. doi: 10.1091/mbc.e09-04-0347. Epub 2009 Jul 1.
Ssd1 is an RNA-binding protein that affects literally hundreds of different processes and is polymorphic in both wild and lab yeast strains. We have used transcript microarrays to compare mRNA levels in an isogenic pair of mutant (ssd1-d) and wild-type (SSD1-V) cells across the cell cycle. We find that 15% of transcripts are differentially expressed, but there is no correlation with those mRNAs bound by Ssd1. About 20% of cell cycle regulated transcripts are affected, and most show sharper amplitudes of oscillation in SSD1-V cells. Many transcripts whose gene products influence longevity are also affected, the largest class of which is involved in translation. Ribosomal protein mRNAs are globally down-regulated by SSD1-V. SSD1-V has been shown to increase replicative life span currency and we show that SSD1-V also dramatically increases chronological life span (CLS). Using a new assay of CLS in pure populations of quiescent prototrophs, we find that the CLS for SSD1-V cells is twice that of ssd1-d cells.
Ssd1是一种RNA结合蛋白，它实际上影响着数百种不同的过程，并且在野生型和实验室酵母菌株中都是多态性的。我们使用转录微阵列来比较同基因的突变体（ssd1-d）和野生型（SSD1-V）细胞在整个细胞周期中的mRNA水平。我们发现15%的转录本存在差异表达，但与Ssd1结合的mRNA没有相关性。约20%受细胞周期调控的转录本受到影响，并且大多数在SSD1-V细胞中显示出更明显的振荡幅度。许多其基因产物影响寿命的转录本也受到影响，其中最大的一类涉及翻译。核糖体蛋白mRNA在SSD1-V中整体下调。SSD1-V已被证明能增加复制寿命，并且我们表明SSD1-V还能显著增加时序寿命（CLS）。使用一种针对静止原养型纯群体中CLS的新检测方法，我们发现SSD1-V细胞的CLS是ssd1-d细胞的两倍。
