ROLE OF micro-RNAs IN THE REGULATION OF GENE EXPRESSION

摘要

Recent discovery of a new class of non-coding interfering RNAs (ncRNAs) enhanced dramatically our knowledge regarding detailed mechanisms for regulation of gene expression. Several subtypes are already described, including microRNAs (miRNAS), small interefering RNAs (siRNAs) and piwi-interacting RNAs (piRNAs). These RNAs are very short in length (20-22 bp) and play significant role in highly specialized non-protein regulatory system for gene activity. Recent years witnessed intensive accumulation ofnew knowledge regarding their function and understanding the mechanism of action. miRNAs are critical post-transcriptional modulators and bind to complementary sequences on target messenger RNA transcripts (mRNAs), leading to repression of translation ordegradation of target RNAs. Until now, more than several hundred miRNAs have been identified in the human genome and it is assumed than 30% of mammalian gene expression is directly regulated by these small RNAs. Dysfunction of miRNA is associated with abnormally expressed and disease related genes.