SELEX and missing phosphate contact analyses reveal flexibility within the AP-2[alpha] protein: DNA binding complex.
The AP-2 family of transcription factors are defined by the presence of a novel DNA binding domain, termed a 'basic helix-span-helix' motif. The AP-2 genes regulate important aspects of vertebrate embryogenesis and have also been linked to the control of cell proliferation and tumorigenesis, but the cellular targets that the AP-2 proteins control are largely undefined. In particular, since only a limited number of sequences have previously been utilized to define the nature of the AP-2 binding site, the range of DNA sequences recognized by the AP-2 proteins remains unknown. We have therefore utilized a SELEX analysis to identify multiple new AP-2[alpha] binding sites. Moreover, we have devised a novel missing phosphate and nucleotide competition analysis to characterize the residues in the binding site required for AP-2[alpha] protein:DNA contact. These studies suggest that the AP-2[alpha] protein:DNA complex is flexible and indicate that AP-2[alpha] can bind three related sequence motifs: GCC N3 GGC, GCC N4 GGC and GCC N3/4 GGG. The availability of these more refined consensus sequences should assist in the identification of target genes for this critical transcription factor.
Mohibullah
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Department of Molecular Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA.
Donner
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A
Ippolito
J A
JA
Williams
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T
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010710:Phosphates; D011485:Protein Binding; D017422:Sequence Analysis, DNA; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D010710:Phosphates; C493673:TFAP2A protein, human; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D004247:DNA