Induction Of CD2AP Gene Expression By All-trans Retinoic Acid Through Sp1/sp3-binding Sites

Objective:CD2AP is an important molecule of glomerular membrane integrity. The reduction of CD2 AP expression was found to be an important reason of glomerulosclerosis. We have reported that CD2 AP is regulated by Sp1/Sp3. Other studies showed that retinoic acid can regulate the combination of Sp1/Sp3 and the promoter binding sites. This study was to investigate the effect of ATRA on CD2 AP transcriptional regulation and its possible mechanism.Methods: Total RNA and protein prepared from cells, with or without ATRA, was subjected to RT-PCR and Western blot analyses. Plasmids containing different length of deletion mutations and site-directed mutations of human CD2 AP promoter were constructed.Promoter activities were tested by luciferase analysis after treating with 0 or 20 μM ATRA for 48 h.Then we performed Ch IP assay to identify whether ATRA can regulate the combination of Sp1/Sp3 and human CD2 AP promoter binding sites. All data were processed by SPSS 13.0 statistical software. Statistical differences were considered to be significant when P<0.05.Resuts: The levels of CD2 AP transcripts and proteins were increased by ATRA. Progressive deletion and site-directed mutagenesis analyse indicated that ATRA increased CD2 AP promoter activity through Sp1/Sp3-A, C binding sites. Ch IP assay revealed that ATRA can increase the ability of Sp1/Sp3 binding to the CD2 AP promoter in vivo.Conclusion: These results indicated that ATRA can upregulate the mRNA and protein levels of the human CD2 AP, by increasing the activation of the human CD2 AP promoter binding to the Sp1/Sp3 sites. ATRA may be effective in treating CD2AP-deficient patient.