Bypassing Sir2 and O-acetyl-ADP-ribose in transcriptional silencing.
The yeast Sir2/3/4 complex forms a heterochromatin-like structure that represses transcription. The proteins nucleate at silencers and spread distally, utilizing the Sir2 NAD(+)-dependent histone deacetylase activity and the affinity of Sir3/4 for deacetylated histone tails. A by-product of the Sir2 reaction, O-acetyl-ADP-ribose (OAADPr), is thought to aid spreading by binding one of the Sir proteins. We developed a protein chimera approach to reexamine the contributions of Sir2. We show that a Sir3 chimera-bearing Hos3, an unrelated NAD(+)-independent histone deacetylase, substitutes for Sir2 in silencing. Sir3-Hos3 operates within the Sir pathway, spreading while deacetylating histones. Moreover, the chimera represses HM loci in strains lacking all five OAADPr-producing deacetylases, indicating that OAADPr is not necessary for silencing. Repression by a Hos3 hybrid bearing the targeting motifs of Sir2 shows that targeting doesn't require the Sir2 reaction. Together, these data demonstrate that protein deacetylation is the only essential function of Sir2 in creating silenced chromatin.
Chou
Chia-Ching
CC
Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA.
Li
Yao-Cheng
YC
Gartenberg
Marc R
MR
D020868:Gene Silencing; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D038961:O-Acetyl-ADP-Ribose / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D056565:Sirtuin 2; D037761:Sirtuins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D038961:O-Acetyl-ADP-Ribose; D011993:Recombinant Fusion Proteins; C084122:SIR3 protein, S cerevisiae; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases
J Biol Chem. 2002 Feb 15;277(7):4778-81
11714726
Biochem Biophys Res Commun. 2000 Nov 30;278(3):685-90
11095969
Mol Biol Cell. 2006 Dec;17(12):5287-97
17035629
Mol Cell. 2006 Oct 20;24(2):211-20
17052455
Nature. 2000 Feb 17;403(6771):795-800
10693811
Proc Natl Acad Sci U S A. 1990 Aug;87(16):6286-90
2201024
Proc Natl Acad Sci U S A. 2000 Dec 19;97(26):14178-82
11106374
Mol Cell Biol. 2007 Apr;27(7):2466-75
17242192
Proc Natl Acad Sci U S A. 1999 Oct 26;96(22):12356-61
10535926
Annu Rev Biochem. 2003;72:481-516
12676793
J Biol Chem. 2002 Nov 22;277(47):45099-107
12297502
Mol Cell Biol. 2001 Dec;21(23):8082-94
11689698
Mol Cell. 2001 Aug;8(2):473-9
11545749
Annu Rev Biochem. 2006;75:435-65
16756498
Cell. 2001 Apr 20;105(2):269-79
11336676
Mol Biol Cell. 2002 Jul;13(7):2207-22
12134062
PLoS Genet. 2007 Aug;3(8):e126
17676954
J Biol Chem. 2002 Apr 12;277(15):12632-41
11812793
Science. 2001 Jan 26;291(5504):650-3
11158677
Mol Cell. 2007 Dec 28;28(6):1015-28
18158899
Methods Enzymol. 2002;350:165-86
12073311
Genes Dev. 1998 Mar 15;12(6):797-805
9512514
Nat Genet. 2002 Nov;32(3):370-7
12410229
J Mol Biol. 2007 Apr 13;367(5):1246-57
17316680
Cell. 2005 May 20;121(4):515-527
15907466
Genetics. 2000 Mar;154(3):1069-83
10757754
Cell. 1985 May;41(1):41-8
3888409
J Biol Chem. 2006 May 19;281(20):14057-65
16565078
Mol Cell. 2007 Sep 21;27(6):890-900
17889663
Proc Natl Acad Sci U S A. 2001 Jan 16;98(2):415-20
11134535
Genes Dev. 2002 Jun 15;16(12):1528-39
12080091
Nat Struct Mol Biol. 2005 Jul;12(7):624-5
15965484
Nat Rev Mol Cell Biol. 2006 Sep;7(9):657-66
16912715
Proc Natl Acad Sci U S A. 2006 Nov 7;103(45):16687-91
17075046
Mol Biol Cell. 1999 Sep;10(9):3045-59
10473645
Mol Cell Biol. 2002 Jun;22(12):4167-80
12024030
EMBO J. 2000 Jun 1;19(11):2641-51
10835361
Nature. 2007 Nov 15;450(7168):440-4
18004385
Cell. 1993 Nov 5;75(3):531-41
8221892
Nat Genet. 2002 Nov;32(3):378-83
12379856
Biochem J. 2007 May 15;404(1):1-13
17447894