RAP1 AND TELOMERE STRUCTURE REGULATE TELOMERE POSITION EFFECTS IN SACCHAROMYCES-CEREVISIAE
RAP1 AND TELOMERE STRUCTURE REGULATE TELOMERE POSITION EFFECTS IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1101/gad.7.7a.1146
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发表时间：
1993-07-01
影响因子：
10.5
通讯作者：
LUSTIG, AJ
中科院分区：
文献类型：
--
作者：
KYRION, G;LIU, K;LUSTIG, AJ
为了研究酵母端粒、沉默和UAS结合蛋白RAP 1在端粒位置效应中的作用，我们描述了两组突变细胞：（1）一组rap 1等位基因（称为rap 1 t等位基因），其产生缺失羧基末端144-165个氨基酸的截短的RAP 1蛋白;和（2）RIF 1基因的无效突变体，其编码能够与RAP 1的羧基末端相互作用的蛋白质。这里提供的数据表明，RAP 1的羧基末端的损失废除在酵母端粒的位置效应，并减少在HML基因座的沉默。这些细胞中位置效应的消除与体内大肠杆菌dam甲基酶的可及性增加有关。因此，端粒位置效应需要RAP 1的羧基末端结构域。相反，rif 1缺失等位基因增加阻遏细胞的频率。使用rap 1 t等位基因产生的野生型细胞不同的端粒道长度，我们还表明，端粒位置的影响是高度敏感的端粒道的大小（或结构）的变化。较长的poly（G1- 3 T）区可以增加端粒转录抑制的频率，表明端粒poly（G1- 3 T）区在亚端粒转录状态的形成或稳定中起着积极的作用。
To investigate the role of the yeast telomere-, silencing-, and UAS-binding protein RAP1 in telomere position effects, we have characterized two sets of mutant cells: (1) a set of rap1 alleles (termed the rap1t alleles) that produce truncated RAP1 proteins missing the carboxy-terminal 144-165 amino acids; and (2) null mutants of the RIF1 gene, encoding a protein capable of interaction with the carboxyl terminus of RAP1. The data presented here indicate that loss of the carboxyl terminus of RAP1 abolishes position effects at yeast telomeres and diminishes silencing at the HML locus. Elimination of position effects in these cells is associated with increased accessibility to the Escherichia coli dam methylase in vivo. Thus, the carboxy-terminal domain of RAP1 is required for telomere position effects. In contrast, rif1 deletion alleles increase the frequency of repressed cells. Using the rap1t alleles to generate wild-type cells differing only in telomere tract lengths, we also show that telomere position effects are highly sensitive to changes in the size (or structure) of the telomeric tract. Longer poly(G1-3T) tracts can increase the frequency of transcriptional repression at the telomere, suggesting that telomeric poly(G1-3T) tracts play an active role in the formation or stability of subtelomeric transcriptional states.