MicroRNA的结构、生物合成及功能

The Structure,Biogenesis and Function of MicroRNA

MicroRNA是真核生物中一类长度约为22个核苷酸的参与基因转录后水平调控的非编码小分子RNA。成熟的microRNA是由较长的可折叠形成发夹结构的前体转录物经过Dicer酶或类似Dicer酶的内切核酸酶加工而来。MicroRNA基因存在于基因组的基因间隔区或者内含子当中。这些小分子RNA通过碱基配对与靶mRNA序列的3′非翻译区或编码区结合以调控基因的表达。它们呈现出组织特异性或发育阶段特异性表达特征。MicroRNA具有调节细胞增殖、死亡、神经细胞分化、个体发育等生物学功能。

MicroRNAs with the length of -22 nucleotide are a growing family of small non-protein-coding RNAs that function as post-transcriptional regulators of target genes and are processed from longer precursors that form stem-loop hairpin structures via Dicer in animals or Dicer-like in plants. MicroRNAs, which are discovered in the intergenic region or intron of pre-mRNA, guide effector complexes to target mRNA by base-pairing to complementary sites in the 3rUTR or coding region of their targets ,facilitating site-specific cleavage or translational repression. Most microRNAs in animal and plant exhibit tissue-specific or developmental-stage-specific expression, indicating that they could play important roles in many biological processes. They have been implied in the control of cell death and proliferation in flies, haematopoietic lineage differentiation in mammals, neuronal patterning in nematodes and leaf and flower development in plants.