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microRNA(miRNA)一般长度为22～25个核苷酸,是能够调控基因表达的小分子非编码RNA(non-coding RNA,ncRRNA),它与细胞的生长、增殖、代谢、分化和凋亡等生物学事件密切相关,并参与肿瘤、糖尿病和病毒感染等众多病理过程。大多数miRNA位于基因间区或者内含子区域,在核内由RNA聚合酶Ⅱ转录产生具有帽子结构和多聚腺苷酸尾的初级miRNA(pri-miRNA),pri-miRNA在核酸酶Drosha及其辅助因子Pasha的作用下被处理成由60～70个核苷酸组成的有发夹结构的miRAN前体(pre-RNA)。此前体被exportin 5转运到细胞质后再由Dicer加工成为具有功能的成熟miRNA。
MicroRNAs (miRNAs) are typically 22-25 nucleotides in length and are small non-coding RNAs (ncRNAs) that regulate gene expression. They are associated with cell growth, proliferation, metabolism, differentiation, and apoptosis Biological events are closely related and are involved in numerous pathological processes such as cancer, diabetes and viral infections. Most miRNAs are located in the intergenic region or intron region and are transcribed in the nucleus by RNA polymerase II to generate primary miRNAs (pri-miRNAs) with a cap structure and polyadenylation tail. The pri-miRNAs are highly conserved in nucleases Drosha and Its cofactor, Pasha, is processed into a hairpin-structured miRAN precursor (pre-RNA) consisting of 60 to 70 nucleotides. This precursor is transported to the cytoplasm by exportin 5 and then processed by Dicer into a functional mature miRNA.