iScience (Sep 2020)

SIRT7 Facilitates CENP-A Nucleosome Assembly and Suppresses Intestinal Tumorigenesis

  • Xiyang Liu,
  • Chengling Li,
  • Qing Li,
  • Hung-Chun Chang,
  • Yun-Chi Tang

Journal volume & issue
Vol. 23, no. 9
p. 101461

Abstract

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Summary: SIRT7 is a member of the mammalian sirtuins and functions as an NAD+-dependent deacylase. Here we show that SIRT7 deficiency leads to a lowered histone acetyltransferase 1 (HAT1) activity and therefore decreased histone H4K5 and H4K12 acetylation. This in turn causes CENP-A dislocation at the centromere, which further affects chromatin assembly. SIRT7 ablation results in aneuploidy and aging phenotypes, including senescence and nucleolar expansion. Moreover, SIRT7 knockout mice are susceptible to DSS-induced colitis and alcohol-derived epithelial disturbance, revealing a disrupted intestinal epithelial homeostasis. Notably, absence of SIRT7 aggravates the susceptibility of colorectal cancer incidence in APCMin/+ mouse model and elicits further the Wnt signaling. Our findings indicate a tumor suppressive role of SIRT7 in the case of colorectal cancer. Together with the activities in maintaining genome integrity and intestinal homeostasis, activating SIRT7 may serve as a strategy to treat bowel diseases and colorectal cancer.

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