Year: 2012
Type: article
Abstract: Mature microRNAs (miRNAs) are evolutionarily conserved small noncoding RNAs that are initially transcribed as primary transcripts [primary microRNAs (pri-miRNAs)]. 1 miRNAs have been identified in a wide range of species, and approximately 1400 are found in humans.It has been estimated that more than 60% of human protein-coding genes are regulated by miRNAs, which thus potentially contribute to health and disease. 2 The majority of pri-miRNAs are located in either introns or exons of protein-coding genes, and the remainder are transcribed from intergenic regions.These pri-miRNAs are reduced in size by the ribonuclease III enzyme Drosha to approximately 70-nucleotide-long stem-loop precursors called precursor microRNAs (pre-miRNAs).These structures are exported into the cytoplasm by exportin 5 and then are processed by Dicer, an endonuclease, to form mature duplex miRNAs; these are then incorporated into an RNA-induced silencing complex (RISC) in which the passenger strand is selectively degraded.Along with Argonaute 2 and other RISC factors, the mature, approximately 20-to 22-nucleotide-long miR-NAs bind to complementary sites on messenger RNA transcripts to induce either translational pausing or, more commonly, transcript degradation.3 The balancing and maintenance of the threshold levels of these miRNAs constitute a highly complex system uniquely designed for the delicate control of gene regulation.
Source: Liver Transplantation
DOI: 10.1002/lt.23377
Authors: Clifford J. Steer, Subbaya Subramanian
Institution: University of Minnesota
Language: English
Subfield: Cancer Research
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2124165058