The cell-specific transcription factor PTF1 contains two different subunits that interact with the DNA.
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.
Roux
E
E
Swiss Cancer Research Institute, Epalinges, Switzerland.
Strubin
M
M
Hagenbüchle
O
O
Wellauer
P K
PK
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
D003432:Cross-Linking Reagents; D015342:DNA Probes; D014157:Transcription Factors; C062602:transcription factor PTF1; D004247:DNA; D000516:alpha-Amylases