Disruption of CDK-resistant chromatin association by pRB causes DNA damage, mitotic errors, and reduces Condensin II recruitment

Authors

Charles A. Ishak, London Regional Cancer Program
Courtney H. Coschi, London Regional Cancer Program
Michael V. Roes, London Regional Cancer Program
Frederick A. Dick, London Regional Cancer ProgramFollow

Document Type

Article

Publication Date

8-3-2017

Journal

Cell Cycle

Volume

16

Issue

15

First Page

1430

Last Page

1439

URL with Digital Object Identifier

10.1080/15384101.2017.1338984

Abstract

Organization of chromatin structure is indispensible to the maintenance of genome integrity. The retinoblastoma tumor suppressor protein (pRB) mediates both transcriptional repression and chromatin organization, but the independent contributions of these functions have been difficult to study. Here, we utilize a synthetic Rb1 mutant allele (F832A) that maintains pRB association at cell cycle gene promoters, but disrupts a cyclin-dependent kinase (CDK)-resistant interaction with E2F1 to reduce occupancy of pRB on intergenic chromatin. Reduced pRB chromatin association increases spontaneous γH2AX deposition and aneuploidy. Our data indicates that the CDK-resistant pRB-E2F1 scaffold recruits Condensin II to major satellite repeats to stabilize chromatin structure in interphase and mitosis through mechanisms that are distinct from silencing of repetitive sequence expression.