Abstract: Objective To study the regulatory effect of the transcription factor cAMP response element binding protein (CREB) on the expression of miR-30a in CD4⁺ lymphocytes. Methods The promoter region of miR-30a gene was determined by UCSC and Ensembl website. The methylation of DNA sequence in the promoter region was calculated on EMBOSS Cpgplot website. The transcription factor binding region and its conservation were analyzed via ECR Browser website. The special binding transcription factors were predicted with support from JASPAR database. Chromatin immunoprecipitation assay was used to confirm the binding of CREB in the promoter region of miR-30a gene in mouse CD4⁺ lymphocytes. According to whether CREB inhibitor KG-501 was added to the culture medium, mouse CD4⁺ lymphocytes were divided into three groups, control, vehicle and KG-501 treated group. The effect of KG-501 on the expression of miR-30a in the cells was detected by RT-qPCR. Results None methylated CpG islands were found in the promoter region of miR-30a gene. The promoter region contained highly conserved transcription factor binding sequences, including several CREB binding sites. Transcription factor CREB bound to the upstream of miR-30a gene promoter region. KG-501 significantly down-regulated the expression of miR-30a(P＜0.05). Conclusions Transcription factor CREB binds to specific sites in the promoter region of miR-30a gene to regulate the expression of miR-30a in mouse CD4⁺ lymphocytes.

Key words: microRNA, DNA methylation, transcription factor, cAMP response element binding protein