Est1 and Cdc13 as comediators of telomerase access
Est1 and Cdc13 as comediators of telomerase access
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DOI：
10.1126/science.286.5437.117
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发表时间：
1999-10-01
期刊：
影响因子：
56.9
通讯作者：
Lundblad, V
中科院分区：
文献类型：
--
作者：
Evans, SK;Lundblad, V
Cdc13和Est1是单链端粒DNA结合蛋白，在酿酒酵母中有助于端粒复制。在这里，它表明，Cdc13的端粒相关的Est1蛋白的融合结果大大延长端粒。由Cdc13或Est 1的突变体组成的融合蛋白赋予相似的端粒延长，表明物理上的紧密接近可以绕过任一蛋白中的端粒酶缺陷突变。将Cdc13直接融合到端粒酶的催化核心，可以在没有Est1的情况下维持稳定的端粒，这与Est1在介导端粒酶进入中的作用一致。因此，端粒长度稳态部分地通过限制端粒酶进入染色体末端来维持，但这种限制情况可以通过将端粒酶直接拴系到端粒来克服。
Cdc13 and Est1 are single-strand telomeric DNA binding proteins that contribute to telomere replication in the yeast Saccharomyces cerevisiae. Here it is shown that fusion of Cdc13 to the telomerase-associated Est1 protein results in greatly elongated telomeres. Fusion proteins consisting of mutant versions of Cdc13 or Est1 confer similar telomere elongation, indicating that close physical proximity can bypass telomerase-defective mutations in either protein. Fusing Cdc13 directly to the catalytic core of telomerase allows stable telomere maintenance in the absence of Est1, consistent with a role for Est1 in mediating telomerase access. Telomere length homeostasis therefore is maintained in part by restricting access of telomerase to chromosome termini, but this limiting situation can be overcome by directly tethering telomerase to the telomere.