[The regulation of vitamin D3 and 9-cis-retinoic acid and their receptors on human hsp90 beta gene].

OBJECTIVE

To study the effects of vitamin D3(VD3), 9-cis-retinoic acid (9-cis-RA) and their receptors on the regulation of human hsp90 beta gene.

METHODS

We first transfected Jurkat cells with "full length" (-1,039 bp/+1,531 bp) hsp90 beta reporter plasmid beta 1.11, then the transfected cells were treated with VD3 or/and 9-cis-RA; or beta 1.11 was cotransfected with wild type vitamin D3 receptor (VDR) or/and retinoid X receptor (RXR) expression construction and the reporter activities were assayed. Western blot was carried out to detect the protein level of hsp90 beta in the Jurkat cells that were transfected by VDR cDNA or treated with VD3 or/and 9-cis-RA. By electrophoresis mobility shift assay (EMSA), we evaluated the DNA binding activity of VDR and RXR in Jurkat cell nuclear extracts.

RESULTS

With VD3 or/and 9-cis-RA treatment, the expression of hsp90 beta gene was slightly increased. The induction became prominent when both of the ligands were present. The unliganded VDR or RXR alpha all slightly repressed the constitutive expression of hsp90 beta gene, while overexpression of VDR and RXR alpha further inhibited the gene. In addition, EMSA results showed that unliganded VDR and RXR simultaneously bound to the vitamin D3 response element (VDRE) of hsp90 beta gene.

CONCLUSIONS

These results suggest that VD3/VDR and 9-cis-RA/RXR co-participate in the regulation of hsp90 beta gene in Jurkat cells.