MiRNA

miRNA or microRNA are a class of small non-coding RNA molecules, typically about 22 nucleotides in length, that function in RNA silencing and post-transcriptional regulation of gene expression. miRNAs are found in plants, animals, and some viruses, and their discovery has provided new and powerful tools for studying gene expression, cell function, and disease.

Function

miRNAs function via base-pairing with complementary sequences within mRNA molecules, usually resulting in gene silencing via translational repression or target degradation. The human genome may encode over 1000 miRNAs, which may target about 60% of mammalian genes and are abundant in many human cell types.

Biogenesis

miRNA biogenesis is a multistep process, involving transcription, processing, and final maturation. The primary miRNA (pri-miRNA) transcript is first processed by the Drosha enzyme to produce a precursor miRNA (pre-miRNA), which is then further processed by the Dicer enzyme to produce the mature miRNA.

Role in disease

Alterations in miRNA expression are implicated in numerous disease states, including cancer, cardiovascular disease, and neurological disorders. As such, miRNAs are being actively investigated as potential biomarkers for disease diagnosis and prognosis, and as potential targets for therapeutic intervention.

See also

• RNA interference
• Gene expression
• Non-coding RNA

References

MiRNA Resources
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