MicroRNA

MicroRNA (miRNA) are a class of small non-coding RNA molecules, functioning in RNA silencing and post-transcriptional regulation of gene expression. miRNAs are approximately 22 nucleotides long and are involved in many biological processes, including development, differentiation, growth, and metabolism.

History

The first miRNA, lin-4, was discovered in 1993 in a study of developmental timing in Caenorhabditis elegans. The term "microRNA" was introduced in 2001.

Biogenesis

miRNA genes are transcribed by RNA polymerase II into primary miRNA (pri-miRNA) molecules, which are then processed by the Drosha enzyme to produce precursor miRNA (pre-miRNA). The pre-miRNA is exported from the nucleus and further processed by the Dicer enzyme to produce the mature miRNA.

Function

miRNAs function by base-pairing with complementary sequences within mRNA molecules, leading to gene silencing either through translational repression or target degradation.

Role in disease

Alterations in miRNA expression are implicated in numerous disease states, including cancer, cardiovascular disease, and neurological disease.

See also

• RNA interference
• Small interfering RNA
• Piwi-interacting RNA

References

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MicroRNA

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  MiRNA
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  Examples of microRNA stem-loops
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  MiRNA biogenesis
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  MicroRNAs and Argonaute RNA binding
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  Role of miRNA in a cancer cell