The PIAS homologue Siz2 regulates perinuclear telomere position and telomerase activity in budding y

Abstract

Budding yeast telomeres are anchored to the nuclear envelope. Siz2-mediated SUMOylation of Yku70/80 and Sir4, both known to mediate telomere anchoring, is found to promote telomere localisation at the nuclear envelope and restrain their elongation. Budding yeast telomeres are reversibly bound at the nuclear envelope through two partially redundant pathways that involve the Sir2/3/4 silencing complex and the Yku70/80 heterodimer1,2. To better understand how this is regulated, we studied the role of SUMOylation in telomere anchoring. We find that the PIAS-like SUMO E3 ligase Siz2 sumoylates both Yku70/80 and Sir4 in vivo and promotes telomere anchoring to the nuclear envelope. Remarkably, loss of Siz2 also provokes telomere extension in a telomerase-dependent manner that is epistatic with loss of the helicase Pif1. Consistent with our previously documented role for telomerase in anchorage3, normal telomere anchoring in siz2 Δ is restored by PIF1 deletion. By live-cell imaging of a critically short telomere, we show that telomeres shift away from the nuclear envelope when elongating. We propose that SUMO-dependent association with the nuclear periphery restrains bound telomerase, whereas active elongation correlates with telomere release.

Cite this article

Ferreira, H., Luke, B., Schober, H. et al. The PIAS homologue Siz2 regulates perinuclear telomere position and telomerase activity in budding yeast. Nat Cell Biol 13, 867–874 (2011). https://doi.org/10.1038/ncb2263

View full text

>> Full Text:   The PIAS homologue Siz2 regulates perinuclear telomere position and telomerase activity in budding y