microRNA

noun

mi·​cro·​RNA ˌmī-krō-ˌär-(ˌ)en-ˈā 

variants or less commonly micro-RNA

genetics

: a short segment of RNA that suppresses gene expression by binding to complementary segments of messenger RNA and interfering with the formation of proteins by translation (see translation sense 2)

The 2006 Nobel Prize honored the discovery of RNA interference … and RNAi has helped shed light on the fact that cells naturally use RNA molecules just 20 to 22 nucleotides long, dubbed microRNAs, to regulate gene expression.

—Jennifer Couzin

called also miRNA

Examples of microRNA in a Sentence

Recent Examples on the Web

The circuit is designed to sense levels of microRNA—molecules that naturally regulate gene expression and give off different signatures in cancer cells versus healthy ones. —Emily Mullin, WIRED, 22 Jan. 2024

In a paper published on 25 September in the journal Nature Nanotechnology, the team demonstrates that the strategy can simultaneously detect 40 biomarkers from human blood serum, including proteins, small RNA pieces called microRNA, and chemicals transmitted by brain cells (neurotransmitters). —IEEE Spectrum, 9 Oct. 2023

Shown are a variety of nucleic acids — messenger RNA (mRNA), microRNA (miRNA), piwi-interacting RNA (piRNA), small nucleolar RNA (snoRNA) — as well as classes of proteins that serve different functions. —Matías A. Loewy, Discover Magazine, 25 Mar. 2023

Bing Yang, a plant science professor at the University of Missouri, said there have been published reports of plant microRNA found in animal blood, which could be evidence of horizontal gene transfer. —Nate Trela, USA TODAY, 7 Apr. 2023

For example, in 2015 Chinese researchers published that the identification of two fragments of an RNA strand (microRNA) in saliva allowed the detection of malignant pancreatic cancer in 7 out of 10 patients with the disease. —Matías A. Loewy, Discover Magazine, 25 Mar. 2023

Preliminary results from his latest mouse studies show that an herb used in traditional Chinese medicine supplies a microRNA that combats the flu virus in the lungs. —Sarah Stanley, Discover Magazine, 21 Dec. 2011

Word History

First Known Use

2001, in the meaning defined above

Medical Definition

microRNA

noun

mi·​cro·​RNA ˌmī-krō-ˌär-en-ˈā 

variants also micro-RNA

: a short segment of RNA that suppresses gene expression by binding to complementary segments of messenger RNA and interfering with the formation of proteins during translation

These microRNAs (miRNAs)—21 to 25 nucleotides in length—are negative regulators of gene expression.

—Paul S. Meltzer, Nature

called also miRNA