title: The cell-specific transcription factor PTF1 contains two different subunits that interact with the DNA.
abstract: The cognate sequence of transcription factor PTF1, which plays a key role in pancreas-specific gene expression, has a bipartite organization. Two separate DNA domains, the A and the B boxes, are required for efficient binding of the factor. The structure of PTF1 was elucidated by cross-linking purified PTF1 to DNA templates that had been differentially substituted with azido-deoxyuridine (N3.dU). This site-directed UV cross-linking shows that PTF1 contains two DNA-binding proteins, distinct in size and sensitivity to Staphylococcus aureus V8 protease. A 64-kD protein is cross-linked with DNA containing N3.dU substitutions in the A box, and a 48-kD protein is cross-linked with DNA containing N3.dU substitutions in the B box. Both proteins bind simultaneously to the same DNA molecule. The data indicate that PTF1 is a heteromeric oligomer and that its cell-specific DNA-binding potential is the result of a concerted activity of two DNA-binding subunits.
authors.affiliation: Swiss Cancer Research Institute, Epalinges, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Roux
authors.forename: M
authors.initials: M
authors.lastname: Strubin
authors.forename: O
authors.initials: O
authors.lastname: Hagenbüchle
authors.forename: P K
authors.initials: PK
authors.lastname: Wellauer
mesh_terms: D000818:Animals; D001483:Base Sequence; D002846:Chromatography, Affinity; D003432:Cross-Linking Reagents / Q000138:chemical synthesis / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D015342:DNA Probes; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D014157:Transcription Factors / Q000378:metabolism / Q000648:ultrastructure*; D014466:Ultraviolet Rays; D000516:alpha-Amylases / Q000235:genetics
chemical_list: D003432:Cross-Linking Reagents; D015342:DNA Probes; D014157:Transcription Factors; C062602:transcription factor PTF1; D004247:DNA; D000516:alpha-Amylases