Functional association between CBP and HNF4 in trans-activation.
CBP functions as a key transcriptional coactivator for a variety of transcription factors. We show here that the hepatocyte nuclear factor 4 (HNF4), a transcription factor in the nuclear receptor superfamily with no defined ligand, is cloned by yeast two-hybrid system using CBP as a bait. GST-pull down assay with nuclear extracts or in vitro translation products revealed that CBP and HNF4 interact with each other at the middle portion (aa 119-375) of HNF4 and two distinct regions (aa 271-451 and 1626-2259) of CBP, respectively, in the ligand-independent manner. Co-transfection experiments indicated that CBP is capable of activating HNF4 site-mediated transcription. These results suggested a functional association between CBP and HNF4 in trans-activation.
Yoshida
E
E
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
Aratani
S
S
Itou
H
H
Miyagishi
M
M
Takiguchi
M
M
Osumu
T
T
Murakami
K
K
Fukamizu
A
A
D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050882:CREB-Binding Protein; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D008099:Liver / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D010750:Phosphoproteins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051557:Hepatocyte Nuclear Factor 4; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C501970:Tcfl4 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D050882:CREB-Binding Protein; C494364:Crebbp protein, mouse; C494365:Crebbp protein, rat