Faculty Collaboration Database

Characterization of the chimeric retinoic acid receptor RARalpha/VDR. Leukemia 1998 Apr;12(4):554-62

Date

04/29/1998

Pubmed ID

9557614

DOI

10.1038/sj.leu.2400937

Scopus ID

2-s2.0-0031978382 (requires institutional sign-in at Scopus site)   6 Citations

Abstract

The chimeric receptor, RARalpha/VDR, contains the DNA-binding domain of the retinoic acid receptor (RARalpha) and the ligand-binding domain of the vitamin D receptor (VDR). The ligand-binding properties of RARalpha/VDR are equivalent to that of VDR, with an observed Kd for 1alpha,25 dihydroxy-vitamin D3 (D3) of 0.5 nM. In CV-1 cells, both RARalpha and RARalpha/VDR induce comparable levels of ligand-mediated transcriptional activity from the retinoic acid responsive reporter gene, beta(RARE)3-TK-luciferase, in the presence of the ligand predicted from the receptor ligand-binding domain. Two chimeric RAR receptors were constructed which contained the ligand-binding domain of the estrogen receptor (ER): RARalpha/ER and ER/RARalpha/ER. Both RARalpha/ER and ER/RARalpha/ER bind beta-estradiol with high affinity, and are transcriptionally active only from palindromic RAREs (TREpal and/or (TRE3)3). Only RARalpha/VDR matched in kind and degree the functional characteristics of RARalpha: (1) maximally active from the beta(RARE); (2) moderately active from the TREs; (3) inactive from the retinoic X receptor response elements (RXREs) ApoA1 and CRBP II; (4) forms heterodimers with RXRalpha; and (5) binds to the betaRARE. F9 embryonal carcinoma cell lines were generated which express RARalpha/VDR mRNA (F9RARalpha/VDR cells) and compared with F9 wild-type (F9-Wt) cells, which do not express VDR mRNA. Treatment with all-trans retinoic acid (tRA) inhibits cell growth and induces the differentiation morphology in both F9-Wt and F9-RARalpha/VDR cells; whereas, treatment with D3 is similarly effective only for F9-RARalpha/VDR cells. It is concluded RARalpha/VDR is an useful 'tool' to pinpoint, or to augment transcription from RAREs in gene pathways controlled by RAR without inhibiting the retinoid responsiveness of endogenous RARs.

Author List

Pemrick SM, Abarzúa P, Kratzeisen C, Marks MS, Medin JA, Ozato K, Grippo JF

Author

Jeffrey A. Medin PhD Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
COS Cells
Cell Differentiation
Cholecalciferol
Dimerization
Estradiol
Kinetics
Mice
Receptors, Calcitriol
Receptors, Estrogen
Receptors, Retinoic Acid
Recombinant Fusion Proteins
Retinoic Acid Receptor alpha
Retinoid X Receptors
Substrate Specificity
Transcription Factors
Transcriptional Activation
Transfection