Minsu Kim/minsu1

what is MicroRNA?

A microRNA (miRNA) is a small non-coding RNA molecule (containing about 22 nucleotides) found in plants, animals and some viruses, that functions in RNA silencing and post-transcriptional regulation of gene expression. miRNA are encoded in the genome as segments of longer transripts. their characteristic structure helps identify them and predict the target genes they might regulate. 

 

Synthesis and Function of miRNA

Structure of pre-miRNAs

overview of the structure of pri-miRNA showing cleavage

miRNAs are derived from precursor RNAs that are encoded by genes. their characteristic structure helps identify them and predict the target genes they might regulate. the functional form of a miRNA IS typically ~21 or 22 nucleotides. These short RNAs are generated by two RNA cleavage reactions from a longer RNA transcript (called a pri-RNA,  for "primary") that carries a hairpin-shaped scondary structure. The first cleavage liverates the stem- loop, called the pre-miRNA ; the second generates the mature miRNA from the pre-miRNA. The two cleavage reactions required to generate the miRNA grom these primary trnascipts are mediated by tow distinct RNases. One is Dicer, and the others is Drosha