Yeast Ku protein plays a direct role in telomeric silencing and counteracts inhibition by Rif proteins

Article Article scientifique Article Yeast Ku protein plays a direct role in telomeric silencing and counteracts inhibition by Rif proteins eng 1999 author Mishra Krishnaveni 503635 author Shore David M. 102587 1123-1126,S1-S2 10.1016/S0960-9822(99)80483-7 0960-9822 https://linkinghub.elsevier.com/retrieve/pii/S0960982299804837 Yku70p/Yku80p, the yeast Ku protein homologue, is a DNA end-binding heterodimer involved in non-homologous end joining. It also binds to telomeres, where it plays an important role in the maintenance of telomeric DNA structure [1], [2], [3], [4], [5]. Ku protein, together with Rap1p, a telomeric DNA (TG₁₋₃ repeat)-binding protein, is also required to initiate transcriptional silencing, or telomere-position effect (TPE). Here, we provide evidence for a direct role of Ku in TPE, which is most likely to be in either the recruitment or activation of Sir4 protein at the telomere. Surprisingly, however, the essential role of Ku in TPE is to overcome the inhibitory effect of two Rap1p-interacting proteins, Rif1p and Rif2p, both of which also play an important role in telomere length regulation [6], [7]. Previous studies showed that Rif and Sir proteins compete for binding to the carboxyl terminus of Rap1p [7], [8], [9]. In the absence of this competition, for example, when RIF genes are mutated, Ku is no longer necessary for TPE, whereas the Rap1p carboxyl terminus is still absolutely required. We show that Rif1p is localized to telomeres, indicating that its inhibitory effect on TPE is direct. Our data implicate a role for Ku in the competition between Sir and Rif proteins for access to the telomeric array of Rap1p molecules, which results in a balance between telomeric silencing and telomere length control. Dewey 570 43 Département de biologie moléculaire 161 false Current Biology 9 19 4b714238-a4fe-4c89-ac78-1219b33836aa Article (Published version) Restricted 1-s2.0-S0960982299804837-main.pdf 102844 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire

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Yeast Ku protein plays a direct role in telomeric silencing and counteracts inhibition by Rif proteins	Current Biology			1999	260	0

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Mishra, Krishnaveni