Cervantes and Quijote protect heterochromatin from aberrant recombination and lead the way to the nuclear periphery.
Repairing double-strand breaks (DSBs) is particularly challenging in heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination and chromosome rearrangements. In Drosophila cells, faithful homologous recombination (HR) repair of heterochromatic DSBs relies on a specialized pathway that relocalizes repair sites to the nuclear periphery before Rad51 recruitment. Here we show that HR progression is initially blocked inside the heterochromatin domain by SUMOylation and the coordinated activity of two distinct Nse2 SUMO E3 ligases: Quijote (Qjt) and Cervantes (Cerv). In addition, the SUMO-targeted ubiquitin ligase (STUbL) Dgrn, but not its partner dRad60, is recruited to heterochromatic DSBs at early stages of repair and mediates relocalization. However, Dgrn is not required to prevent Rad51 recruitment inside the heterochromatin domain, suggesting that the block to HR progression inside the domain and relocalization to the nuclear periphery are genetically separable pathways. Further, SUMOylation defects affect relocalization without blocking heterochromatin expansion, revealing that expansion is not required for relocalization. Finally, nuclear pores and inner nuclear membrane proteins (INMPs) anchor STUbL/RENi components and repair sites to the nuclear periphery, where repair continues. Together, these studies reveal a critical role of SUMOylation and nuclear architecture in the spatial and temporal regulation of heterochromatin repair and the protection of genome integrity.
a University of Southern California , Molecular and Computational Biology Department , Los Angeles , CA , USA.
Taehyun
T
Ryu
a University of Southern California , Molecular and Computational Biology Department , Los Angeles , CA , USA.
Melissa R
MR
Bonner
a University of Southern California , Molecular and Computational Biology Department , Los Angeles , CA , USA.
Irene
I
Chiolo
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D006570:Heterochromatin / Q000235:genetics* / Q000378:metabolism; D059765:Homologous Recombination; D006801:Humans; D008025:Ligases / Q000378:metabolism*; D058207:Sumoylation / Q000235:genetics
D029721:Drosophila Proteins; D006570:Heterochromatin; D008025:Ligases
DSB repair; Heterochromatin; Homologous recombination; Nse2; Nuclear architecture; Nuclear periphery; RENi; STUbL; SUMOylation
Cold Spring Harb Perspect Biol. 2015 Nov 02;7(11):null
26525148
Genes Dev. 2008 Jun 1;22(11):1478-89
18519640
Proteins. 2010 May 1;78(6):1491-502
20077568
Cell. 2010 Feb 5;140(3):372-83
20144761
Curr Opin Cell Biol. 2015 Jun;34:1-8
25863918
Nat Struct Mol Biol. 2011 Jun 05;18(7):831-9
21642969
Cell. 2011 Mar 4;144(5):732-44
21353298
Genes Dev. 2016 Jul 15;30(14 ):1645-57
27474442
Nat Cell Biol. 2010 Feb;12 (2):177-84
20081839
Nucleic Acids Res. 2015 Sep 18;43(16):7931-44
26206670
Genes Dev. 2012 Jun 1;26(11):1179-95
22661229
Nat Struct Mol Biol. 2009 May;16(5):509-16
19363481
Genes Dev. 2009 Apr 15;23 (8):912-27
19390086
Mol Cell Biol. 2005 Jan;25(1):172-84
15601840
Nature. 2008 May 29;453(7195):682-6
18438399
Mutat Res. 2013 Oct;750(1-2):56-66
23958412
Science. 2007 Jun 15;316(5831):1625-8
17569867
Nat Cell Biol. 2009 Nov;11(11):1376-82
19783983
Cell Rep. 2014 Dec 11;9(5):1703-17
25464843
J Cell Biol. 2006 Jan 16;172(2):189-99
16418532
EMBO J. 2009 Nov 4;28(21):3413-27
19779458
Cell. 2012 Nov 9;151(4):807-20
23122649
Sci Signal. 2012 Dec 04;5(253):ra88
23211528
Nucleic Acids Res. 2013 Jun;41(11):5784-98
23589625
Cell. 2010 Feb 5;140(3):360-71
20144760
Mol Cell. 2009 Sep 11;35(5):657-68
19748359
PLoS Genet. 2012;8(5):e1002667
22589731
J Biol Chem. 2007 Nov 23;282(47):34176-84
17848550
Mol Cell. 2012 Feb 10;45(3):422-32
22285753
Mutat Res. 2010 Apr-Jun;704(1-3):78-87
20060491
Nat Rev Genet. 2008 Dec;9(12):923-37
19002142
J Cell Biol. 2011 Apr 4;193(1):81-95
21464229
Mol Cell. 2009 Feb 13;33(3):335-43
19217407
J Biol Chem. 2002 Aug 30;277(35):31663-72
12077133
PLoS Genet. 2010 Feb 12;6(2):e1000846
20174442
Genome Res. 2011 Feb;21(2):147-63
21177972
Mol Cell. 2014 Aug 21;55(4):626-39
25066231
EMBO J. 2007 Sep 19;26(18):4102-12
17762864
Science. 2008 Oct 24;322(5901):597-602
18948542
J Biol Chem. 2007 Nov 23;282(47):34167-75
17728242
Nucleic Acids Res. 2011 Aug;39(15):6489-99
21511815
Nat Cell Biol. 2015 Nov;17(11):1401-11
26502056
Genome Res. 2015 Mar;25(3):445-58
25589440
Mol Cell. 2016 Jul 21;63(2):293-305
27397684
EMBO J. 2007 Sep 19;26(18):4089-101
17762865
Cell Rep. 2016 May 10;15(6):1242-53
27134164
Mol Biol Evol. 2006 Nov;23(11):2191-202
16916943
Cold Spring Harb Perspect Biol. 2015 Aug 03;7(8):a016501
26238353
J Biol Chem. 2007 Jul 13;282(28):20388-94
17502373
Curr Opin Genet Dev. 2008 Apr;18(2):204-11
18372168
PLoS One. 2011;6(9):e25439
21966530
Cell Cycle. 2013 Feb 1;12(3):422-9
23287531
Mol Cell. 2008 Jul 25;31(2):167-77
18657500
J Cell Biol. 2009 May 18;185(4):577-86
19451271
Genes Dev. 2015 May 15;29(10):1006-17
25940904
PLoS Genet. 2013;9(8):e1003670
23935535
Nature. 2014 Aug 28;512(7515):449-52
25164756
Genes Dev. 2016 Apr 15;30(8):931-45
27056668
Nature. 2001 Feb 15;409(6822):860-921
11237011
Science. 2003 Jun 6;300(5625):1542-8
12791985