Solution structure of the interacting domains of the Mad-Sin3 complex: implications for recruitment of a chromatin-modifying complex.
Gene-specific targeting of the Sin3 corepressor complex by DNA-bound repressors is an important mechanism of gene silencing in eukaryotes. The Sin3 corepressor specifically associates with a diverse group of transcriptional repressors, including members of the Mad family, that play crucial roles in development. The NMR structure of the complex formed by the PAH2 domain of mammalian Sin3A with the transrepression domain (SID) of human Mad1 reveals that both domains undergo mutual folding transitions upon complex formation generating an unusual left-handed four-helix bundle structure and an amphipathic alpha helix, respectively. The SID helix is wedged within a deep hydrophobic pocket defined by two PAH2 helices. Structure-function analyses of the Mad-Sin3 complex provide a basis for understanding the underlying mechanism(s) that lead to gene silencing.
Brubaker
K
K
Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA.
Cowley
S M
SM
Huang
K
K
Loo
L
L
Yochum
G S
GS
Ayer
D E
DE
Eisenman
R N
RN
Radhakrishnan
I
I
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D020868:Gene Silencing; D006655:Histone Deacetylases; D006801:Humans; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009687:Nuclear Proteins; D010446:Peptide Fragments / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; C501382:MAD1 protein, S cerevisiae; C501384:MAD1L1 protein, human; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D012097:Repressor Proteins; C071731:SIN3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D006655:Histone Deacetylases