The directly repeated RG(G/T)TCA motifs of the rat and mouse cellular retinol-binding protein II genes are promiscuous binding sites for RAR, RXR, HNF-4, and ARP-1 homo- and heterodimers - PubMed (original) (raw)

Comparative Study

. 1994 Jan 14;269(2):890-902.

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Comparative Study

The directly repeated RG(G/T)TCA motifs of the rat and mouse cellular retinol-binding protein II genes are promiscuous binding sites for RAR, RXR, HNF-4, and ARP-1 homo- and heterodimers

H Nakshatri et al. J Biol Chem. 1994.

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Abstract

We show here that the element which was previously characterized as a retinoid X receptor (RXR)-specific response element (RXRE) in the rat cellular retinol-binding protein II (CRBPII) gene is not conserved in the mouse gene. However, two conserved cis-acting elements (RE2 and RE3) located in the promoter region of the mouse and rat CRBPII genes mediate transactivation by retinoic acid receptors (RARs) and RXRs in transfected Cos-1, CV-1, and HeLa cells. The element RE3 which is the major retinoic acid (RA) response element also binds the transcription factors HNF-4 and ARP-1. HNF-4 constitutively activates the mouse CRBPII promoter, whereas ARP-1 represses the activation mediated by RARs, RXRs, and HNF-4. In contrast, RA has no effect on the activity of the mouse CRBPII promoter in the human colon carcinoma cell line CaCo-2 which constitutively expresses RAR alpha, RAR gamma, RXR alpha, HNF-4, and ARP-1, under conditions where the activity of the RAR beta 2 gene promoter is readily induced by RA. Our results suggest that the CRBPII gene may not be RA-inducible in tissues expressing HNF-4 and ARP-1, and that the RA inducibility of the CRBPII gene promoter observed in transfection experiments reflects the promiscuous binding of RARs/RXRs to HNF-4 and ARP-1 response elements.

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