Molecular basis for recognition of methylated and specific DNA sequences by the zinc finger protein Kaiso.
Proc Natl Acad Sci U S A
; 109(38): 15229-34, 2012 Sep 18.
Article
em En
| MEDLINE
| ID: mdl-22949637
ABSTRACT
Methylation of CpG dinucleotides in DNA is a common epigenetic modification in eukaryotes that plays a central role in maintenance of genome stability, gene silencing, genomic imprinting, development, and disease. Kaiso, a bifunctional Cys(2)His(2) zinc finger protein implicated in tumor-cell proliferation, binds to both methylated CpG (mCpG) sites and a specific nonmethylated DNA motif (TCCTGCNA) and represses transcription by recruiting chromatin remodeling corepression machinery to target genes. Here we report structures of the Kaiso zinc finger DNA-binding domain in complex with its nonmethylated, sequence-specific DNA target (KBS) and with a symmetrically methylated DNA sequence derived from the promoter region of E-cadherin. Recognition of specific bases in the major groove of the core KBS and mCpG sites is accomplished through both classical and methyl CH···O hydrogen-bonding interactions with residues in the first two zinc fingers, whereas residues in the C-terminal extension following the third zinc finger bind in the opposing minor groove and are required for high-affinity binding. The C-terminal region is disordered in the free protein and adopts an ordered structure upon binding to DNA. The structures of these Kaiso complexes provide insights into the mechanism by which a zinc finger protein can recognize mCpG sites as well as a specific, nonmethylated regulatory DNA sequence.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fatores de Transcrição
Limite:
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article