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Nat Cell Biol. 2015 Nov;17(11):1401-11. doi: 10.1038/ncb3258. Epub 2015 Oct 26.

Heterochromatic breaks move to the nuclear periphery to continue recombinational repair.

Author information

1
University of Southern California, Molecular and Computational Biology Department, Los Angeles, California 90089, USA.
2
Lawrence Berkeley National Laboratory, Genome Dynamics Department, Berkeley, California 94720, USA.
3
University of California Berkeley, Molecular and Cell Biology Department, Berkeley, California 94720, USA.

Abstract

Heterochromatin mostly comprises repeated sequences prone to harmful ectopic recombination during double-strand break (DSB) repair. In Drosophila cells, 'safe' homologous recombination (HR) repair of heterochromatic breaks relies on a specialized pathway that relocalizes damaged sequences away from the heterochromatin domain before strand invasion. Here we show that heterochromatic DSBs move to the nuclear periphery to continue HR repair. Relocalization depends on nuclear pores and inner nuclear membrane proteins (INMPs) that anchor repair sites to the nuclear periphery through the Smc5/6-interacting proteins STUbL/RENi. Both the initial block to HR progression inside the heterochromatin domain, and the targeting of repair sites to the nuclear periphery, rely on SUMO and SUMO E3 ligases. This study reveals a critical role for SUMOylation in the spatial and temporal regulation of HR repair in heterochromatin, and identifies the nuclear periphery as a specialized site for heterochromatin repair in a multicellular eukaryote.

PMID:
26502056
PMCID:
PMC4628585
DOI:
10.1038/ncb3258
[Indexed for MEDLINE]
Free PMC Article

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