Genetic identification of a network of factors that functionally interact with the nucleosome remodeling ATPase ISWI.
Nucleosome remodeling and covalent modifications of histones play fundamental roles in chromatin structure and function. However, much remains to be learned about how the action of ATP-dependent chromatin remodeling factors and histone-modifying enzymes is coordinated to modulate chromatin organization and transcription. The evolutionarily conserved ATP-dependent chromatin-remodeling factor ISWI plays essential roles in chromosome organization, DNA replication, and transcription regulation. To gain insight into regulation and mechanism of action of ISWI, we conducted an unbiased genetic screen to identify factors with which it interacts in vivo. We found that ISWI interacts with a network of factors that escaped detection in previous biochemical analyses, including the Sin3A gene. The Sin3A protein and the histone deacetylase Rpd3 are part of a conserved histone deacetylase complex involved in transcriptional repression. ISWI and the Sin3A/Rpd3 complex co-localize at specific chromosome domains. Loss of ISWI activity causes a reduction in the binding of the Sin3A/Rpd3 complex to chromatin. Biochemical analysis showed that the ISWI physically interacts with the histone deacetylase activity of the Sin3A/Rpd3 complex. Consistent with these findings, the acetylation of histone H4 is altered when ISWI activity is perturbed in vivo. These findings suggest that ISWI associates with the Sin3A/Rpd3 complex to support its function in vivo.
Burgio
Giosalba
G
Dipartimento di Scienze Biochimiche, Universita' degli Studi di Palermo, Palermo, Italy.
La Rocca
Gaspare
G
Sala
Anna
A
Arancio
Walter
W
Di Gesù
Dario
D
Collesano
Marianna
M
Sperling
Adam S
AS
Armstrong
Jennifer A
JA
van Heeringen
Simon J
SJ
Logie
Colin
C
Tamkun
John W
JW
Corona
Davide F V
DF
D000107:Acetylation; D000251:Adenosine Triphosphatases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D002875:Chromosomes / Q000737:chemistry / Q000235:genetics; D029721:Drosophila Proteins / Q000032:analysis / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005260:Female; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000032:analysis / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D012097:Repressor Proteins / Q000032:analysis / Q000378:metabolism*; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
D002843:Chromatin; D029721:Drosophila Proteins; D006657:Histones; C086468:ISWI protein; D009687:Nuclear Proteins; D009707:Nucleosomes; D012097:Repressor Proteins; C099683:SIN3A transcription factor; D014157:Transcription Factors; C512966:HDAC1 protein, Drosophila; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D000251:Adenosine Triphosphatases