Hepatocyte nuclear factor-4 activates medium chain acyl-CoA dehydrogenase gene transcription by interacting with a complex regulatory element.
We have recently identified a complex transcriptional regulatory element in the medium chain acyl-CoA dehydrogenase (MCAD) gene promoter region that confers response to retinoids through interaction with receptors for all-trans-retinoic acid (RARs) and 9-cis-retinoic acid (RXRs) (Raisher, B. D., Gulick, T., Zhang, Z., Strauss, A. W., Moore, D. D., and Kelly, D. P. (1992) J. Biol. Chem. 267, 20264-20269). We examined the interaction of this element (RAREMCAD) with hepatocyte nuclear factor-4 (HNF-4), an orphan receptor with a tissue expression pattern similar to that of MCAD. Electrophoretic mobility shift assays and cotransfection experiments showed that HNF-4 binds with high affinity to RAREMCAD to activate transcription by an RXR-independent mechanism. Mutational analysis revealed that the MCAD HNF-4 response element consists of an imperfect direct repeat homologous to the consensus sequence for binding to the thyroid receptor/RAR/RXR subgroup of receptors and that distinct sequence requirements dictate HNF-4 binding and transactivation. Mobility shift assays with anti-HNF-4 antiserum demonstrated that the MCAD HNF-4 response element binds endogenous rat liver HNF-4 supporting its role in the regulation of MCAD gene expression in vivo. Thus, HNF-4 activates MCAD gene transcription via a complex regulatory element, the architecture of which carries important implications for the structure of HNF-4 response elements in general.
Carter
M E
ME
Department of Medicine, Washington University, St. Louis, Missouri 63110.
Gulick
T
T
Raisher
B D
BD
Caira
T
T
Ladias
J A
JA
Moore
D D
DD
Kelly
D P
DP
D016475:3T3 Cells; D042964:Acyl-CoA Dehydrogenase; D044944:Acyl-CoA Dehydrogenases / Q000096:biosynthesis* / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D051557:Hepatocyte Nuclear Factor 4; D051379:Mice; D008969:Molecular Sequence Data; D010750:Phosphoproteins; D011401:Promoter Regions, Genetic; D051381:Rats; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D010750:Phosphoproteins; D011988:Receptors, Thyroid Hormone; D011994:Recombinant Proteins; C501970:Tcfl4 protein, mouse; D014157:Transcription Factors; D014212:Tretinoin; D044944:Acyl-CoA Dehydrogenases; D042964:Acyl-CoA Dehydrogenase