miRNA-Dependent CD4⁺ T Cell Differentiation in the Pathogenesis of Multiple Sclerosis

Figure 2

(a) Primary miRNA transcripts (pri-miRNAs) are processed in the nucleus via DROSHA and DGCR8 into pre-miRNAs. Pre-miRNAs are transported by XPO5 and RAN-GTP to the cytoplasm, where they are further transformed by Dicer and TARBP2 into mature molecules. (b) Methylation of the miRNA promoter sequence may have a direct effect on miRNA biogenesis. The MECP2 protein, by binding to methylated sequences, inhibits transcription and allows pri-miRNA processing, which increases the level of mature miRNAs. (c) Mature miRNAs can silence expression of target genes through two main mechanisms: repression of translation through the RISC complex and direct transcript degradation by AGO2.