Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
Biochemistry. 2013 Feb 19;52(7):1131-3. doi: 10.1021/bi3015218. Epub 2013 Feb 7.
In budding yeast, association of the Est1 regulatory protein with telomerase is thought to be limited to the late S phase, when telomere elongation occurs. By monitoring the stoichiometry of telomerase subunits, we show instead that a telomerase complex containing Est1 is assembled much earlier in the cell cycle. We also report a biochemical interaction between Est1 and the telomere binding protein Cdc13 that recapitulates the previously observed genetic relationship between EST1 and CDC13. This supports a model in which regulated binding of Cdc13 to chromosome termini dictates subsequent interaction of a recruitment-competent telomerase complex with telomeres.
在芽殖酵母中，Est1 调节蛋白与端粒酶的结合被认为仅限于晚期 S 期，此时发生端粒延伸。通过监测端粒酶亚基的化学计量，我们反而表明，含有 Est1 的端粒酶复合物在细胞周期的早期就已组装。我们还报告了 Est1 和端粒结合蛋白 Cdc13 之间的生化相互作用，这再现了 EST1 和 CDC13 之间先前观察到的遗传关系。这支持了这样一种模型，即 Cdc13 与染色体末端的调节结合决定了随后具有招募能力的端粒酶复合物与端粒的相互作用。
