A common DNA-binding site for SZF1 and the BRCA1-associated zinc finger protein, ZBRK1.
More than 220 Kruppel-associated box-zinc finger protein (KRAB-ZFP) genes are encoded in the human genome. KRAB-ZFPs function as transcriptionalrepressors by binding DNA through their tandem zinc finger motifs.Gene silencing is mediated by the highly conserved KRAB domain, which recruits histone deacetylase complexes, histone methylases, and heterochromatin proteins. However, little is known of the biological programs regulated by KRAB-ZFPs, in large part because of the difficulty in identifying DNA-binding sites recognized by long arrays of zinc fingers. In an attempt to identify the natural target genes for a KRAB-ZFP, we chose SZF1, a hematopoietic progenitor-restricted, KRAB-ZFP that contains only four C(2)H(2) zinc finger motifs. Using recombinant SZF1 protein and a PCR-based binding site selection strategy, we identified a 15-bp consensus DNA sequence recognized by SZF1. Remarkably, this sequence is similar to the core DNA-binding site described recently for ZBRK1, a KRAB-ZFP that binds to BRCA1 and is involved in coordinating the cellular DNA damage response. The SZF1 and ZBRK1 proteins bind to both the experimentally derived SZF1 site and the canonical ZBRK1 site. The KRAB domain from SZF1 bound directly to the KAP-1 corepressor and displayed intrinsic silencing activity. Moreover, full-length SZF1 repressed a promoter containing ZBRK1 recognition sequences. Thus, SZF1 and ZBRK1 may regulate a common set of target genes in vivo.
Peng
Hongzhuang
H
The Wistar Institute, Philadelphia, Pennsylvania 19104, USA.
Zheng
Lei
L
Lee
Wen-Hwa
WH
Rux
John J
JJ
Rauscher
Frank J
FJ
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006412:Hematopoietic Stem Cells / Q000378:metabolism / Q000502:physiology; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D009687:Nuclear Proteins; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000076183:Tripartite Motif-Containing Protein 28; D016335:Zinc Fingers / Q000235:genetics / Q000502:physiology*
D019313:BRCA1 Protein; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C422407:ZNF350 protein, human; C117566:ZNF589 protein, human; D004247:DNA; C101116:TRIM28 protein, human; C103190:Trim28 protein, mouse; D000076183:Tripartite Motif-Containing Protein 28