Adf-1 Is a Nonmodular Transcription Factor That Contains a TAF-Binding Myb-Like Motif

AUTOR(ES)

Cutler, Gene

FONTE

American Society for Microbiology

RESUMO

Adf-1 is an essential Drosophila melanogaster sequence-specific transactivator that binds the promoters of a diverse group of genes. We have performed a comprehensive mapping of the functional domains of Adf-1 to study the role of transactivators in the process of gene activation. Using a series of clustered point mutations and small deletions we have identified regions of Adf-1 required for DNA binding, dimerization, and activation. In contrast to most enhancer-binding factors, the Adf-1 activation regions are nonmodular and depend on an intact protein, including the Adf-1 DNA-binding domain, for activity. Like many transcriptional activators, Adf-1 contains a TFIID-binding domain that can interact with specific TAF subunits. Although TAFs are required for Adf-1-directed activation, TAF binding is not sufficient, suggesting that Adf-1 may direct multiple essential steps during activation. Interestingly, both the TAF-binding domain and the DNA-binding domain contain sequences homologous to those of the Myb family of DNA-binding domains. Thus, Adf-1 has evolved an unusual structure containing two versions of the Myb motif, one that binds DNA and one that binds proteins.

Documentos Relacionados

• Interaction of D-type cyclins with a novel myb-like transcription factor, DMP1.
• Cloning of Drosophila transcription factor Adf-1 reveals homology to Myb oncoproteins.
• Alternatively spliced products of the maize P gene encode proteins with homology to the DNA-binding domain of myb-like transcription factors.
• Sequence-specific DNA recognition by the myb-like domain of the human telomere binding protein TRF1: a model for the protein-DNA complex.
• Mutations in the yeast Myb-like protein Bas1p resulting in discrimination between promoters in vivo but notin vitro.