The transactivation potential of variant hepatocyte nuclear factor 1 is modified by alternative splicing.
Two forms of the transcription factor vHNF1 (HNF1 beta or LFB3) have been previously described, derived by alternative splicing from a common premessenger RNA, and have been called vHNF1-A and vHNF1-B. vHNF1 proteins share a homologous homeo-related DNA-binding domain with the HNF1 protein, initially characterized as a liver-restricted transcription factor, and bind to a similar sequence motif. Here we demonstrate that vHNF1-A is a stronger transactivator than vHNF1-B when assayed in transient transfections using two different promoters. vHNF1-A also binds DNA with a higher affinity suggesting that a region of the protein located immediately upstream of the homeodomain can modulate the protein/DNA interaction and transactivation. Both vHNF1 transcripts were found at a constant ratio in every tissue where vHNF1 expression could be detected, using a quantitative reverse transcriptase-polymerase chain reaction.
Ringeisen
F
F
Unité des Virus Oncogènes, UA 1644 du CNRS, Département des Biotechnologies, Institut Pasteur, Paris, France.
Rey-Campos
J
J
Yaniv
M
M
D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D002460:Cell Line; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D005260:Female; D014644:Genetic Variation; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides / Q000378:metabolism / Q000494:pharmacology; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D051381:Rats; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms
D017931:DNA Primers; D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; C496495:HNF1B protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; C496489:Hnf1a protein, rat; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta