PMID- 8395017
OWN - NLM
STAT- MEDLINE
DCOM- 19930923
LR  - 20210526
IS  - 0270-7306 (Print)
IS  - 1098-5549 (Electronic)
IS  - 0270-7306 (Linking)
VI  - 13
IP  - 9
DP  - 1993 Sep
TI  - Retinoid X receptors stimulate and 9-cis retinoic acid inhibits 
      1,25-dihydroxyvitamin D3-activated expression of the rat osteocalcin gene.
PG  - 5907-17
AB  - The vitamin D receptor (VDR) binds the vitamin D-responsive element (VDRE) as a 
      heterodimer with an unidentified receptor auxiliary factor (RAF) present in 
      mammalian cell nuclear extracts. VDR also interacts with the retinoid X receptors 
      (RXRs), implying that RAF may be related to the RXRs. Here we demonstrate that 
      highly purified HeLa cell RAF contained RXR beta immunoreactivity and that both 
      activities copurified and precisely coeluted in high-resolution hydroxylapatite 
      chromatography. Furthermore, an RXR beta-specific antibody disrupted VDR-RAF-VDRE 
      complexes in mobility shift assays. These data strongly indicate that HeLa RAF is 
      highly related to or is identical to RXR beta. Consequently, the effect of the 
      9-cis retinoic acid ligand for RXRs was examined in 1,25-dihydroxyvitamin D3 
      [1,25(OH)2D3]-activated gene expression systems. Increasing concentrations of 
      9-cis retinoic acid (1 nM to 1 microM) markedly reduced 1,25(OH)2D3-dependent 
      accumulation of osteocalcin mRNA in osteoblast-like ROS 17/2.8 cells. All-trans 
      retinoic acid also interfered with vitamin D responsiveness, but it was 
      consistently less potent than the 9-cis isomer. Transient transfection studies 
      revealed that attenuation by 9-cis retinoic acid was at the transcriptional level 
      and was mediated through interactions at the osteocalcin VDRE. Furthermore, 
      overexpression of both RXR beta and RXR alpha augmented 1,25(OH)2D3 
      responsiveness in transient expression studies. Direct analysis of VDRE binding 
      in mobility shift assays demonstrated that heteromeric interactions between VDR 
      and RXR were enhanced by 1,25(OH)2D3 and were not affected appreciably by 9-cis 
      retinoic acid, except that inhibition was observed at high retinoid 
      concentrations. These data suggest a regulatory mechanism for osteocalcin gene 
      expression that involves 1,25(OH)2D3-induced heterodimerization of VDR and 
      unliganded RXR. 9-cis retinoic acid may attenuate 1,25(OH)2D3 responsiveness by 
      diverting RXRs away from VDR-mediated transcription and towards other 
      RXR-dependent transcriptional pathways.
FAU - MacDonald, P N
AU  - MacDonald PN
AD  - Department of Biochemistry, University of Arizona College of Medicine, Tuscon 
      85724.
FAU - Dowd, D R
AU  - Dowd DR
FAU - Nakajima, S
AU  - Nakajima S
FAU - Galligan, M A
AU  - Galligan MA
FAU - Reeder, M C
AU  - Reeder MC
FAU - Haussler, C A
AU  - Haussler CA
FAU - Ozato, K
AU  - Ozato K
FAU - Haussler, M R
AU  - Haussler MR
LA  - eng
GR  - 1-F32-GM-13846/GM/NIGMS NIH HHS/United States
GR  - AR-15781/AR/NIAMS NIH HHS/United States
GR  - DK-33351/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Mol Cell Biol
JT  - Molecular and cellular biology
JID - 8109087
RN  - 0 (Ligands)
RN  - 0 (RNA, Messenger)
RN  - 0 (Receptors, Calcitriol)
RN  - 0 (Receptors, Cell Surface)
RN  - 0 (Receptors, Retinoic Acid)
RN  - 0 (Receptors, Steroid)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Retinoid X Receptors)
RN  - 0 (Transcription Factors)
RN  - 104982-03-8 (Osteocalcin)
RN  - 5688UTC01R (Tretinoin)
RN  - FXC9231JVH (Calcitriol)
SB  - IM
MH  - Animals
MH  - Calcitriol/antagonists & inhibitors/*pharmacology
MH  - Gene Expression
MH  - *Gene Expression Regulation
MH  - HeLa Cells
MH  - Humans
MH  - Ligands
MH  - Osteocalcin/*genetics
MH  - Promoter Regions, Genetic
MH  - RNA, Messenger/genetics
MH  - Rats
MH  - Receptors, Calcitriol
MH  - Receptors, Cell Surface/*physiology
MH  - *Receptors, Retinoic Acid
MH  - Receptors, Steroid/*physiology
MH  - Recombinant Proteins/metabolism
MH  - Retinoid X Receptors
MH  - *Transcription Factors
MH  - Tretinoin/*pharmacology
PMC - PMC360339
EDAT- 1993/09/01 00:00
MHDA- 1993/09/01 00:01
PMCR- 1993/09/01
CRDT- 1993/09/01 00:00
PHST- 1993/09/01 00:00 [pubmed]
PHST- 1993/09/01 00:01 [medline]
PHST- 1993/09/01 00:00 [entrez]
PHST- 1993/09/01 00:00 [pmc-release]
AID - 10.1128/mcb.13.9.5907-5917.1993 [doi]
PST - ppublish
SO  - Mol Cell Biol. 1993 Sep;13(9):5907-17. doi: 10.1128/mcb.13.9.5907-5917.1993.