Exocrine pancreas transcription factor 1 binds to a bipartite enhancer element and activates transcription of acinar genes.
Exocrine pancreas (XP) enhancers, which contain a conserved core sequence, are active only in XP cells. A core enhancer-binding activity also appears to be restricted to XP nuclei. Here we describe the properties of a factor, purified approximately 100,000-fold from pancreas nuclei, which displays core enhancer-binding activity. It is not identical to previously characterized factors and is termed exocrine pancreas transcription factor 1 (XPF-1). In the highly purified preparation, only a single major protein of 60 kDa was detected by silver staining on sodium dodecyl sulfate-gels and by UV cross-linking. XPF-1 binds to the core enhancer of all tested XP genes and not to a mutant sequence which is inactive in vivo. High-affinity binding sites are bipartite. The results of competition binding and UV-cross-linking assays suggest that XPF-1 interacts with both motifs. XPF-1 selectively stimulates transcription of core enhancer templates in an in vitro transcription system. We hypothesize that XPF-1 plays a role in activation of the transcription of XP-specific genes.
Weinrich
S L
SL
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0534.
Meister
A
A
Rutter
W J
WJ
D000681:Amylases / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002918:Chymotrypsin / Q000235:genetics; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
D046911:Macromolecular Substances; D014157:Transcription Factors; C071030:XPF-1 protein, human; D000681:Amylases; D002918:Chymotrypsin; D010196:Pancreatic Elastase