Transcriptional activation by hepatocyte nuclear factor-4 in a cell-free system derived from rat liver nuclei.
Hepatocyte nuclear factor-4 (HNF4) regulates gene expression by binding to direct repeat motifs of the RG(G/T)TCA sequence separated by one nucleotide (DR1). In this study we demonstrate that endogenous HNF4 present in rat liver nuclear extracts, as well as purified recombinant HNF4, activates transcription from naked DNA templates containing multiple copies of the DR1 element linked to the adenovirus major late promoter. Recombinant HNF4 also activates transcription from the rat cellular retinol binding protein II (CRBPII) promoter in vitro. The region between -105 and -63 bp of this promoter is essential for HNF-mediated transactivation. The addition of a peptide containing the LXXLL motif abolished HNF4-mediated transactivation in vitro suggesting that LXXLL-containing protein factor(s) are involved in HNF4-mediated transactivation in rat liver nuclear extracts. This is the first report on transactivation by HNF4 in a cell-free system derived from rat liver nuclei.
Harish
S
S
Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
Khanam
T
T
Mani
S
S
Rangarajan
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism*; D002474:Cell-Free System / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D051557:Hepatocyte Nuclear Factor 4; D008099:Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism*; D012177:Retinol-Binding Proteins / Q000235:genetics; D054840:Retinol-Binding Proteins, Cellular; D017386:Sequence Homology, Amino Acid; D013698:Templates, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects
D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D009842:Oligopeptides; D010750:Phosphoproteins; C518461:Rbp2 protein, rat; D011994:Recombinant Proteins; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular; D014157:Transcription Factors; D004247:DNA