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

This means that microRNA helps control when and how much a particular protein should be made. —Paul Smaglik, Discover Magazine, 30 Oct. 2024

Fletcher said the most advanced studies to date are reviewing how microRNA approaches might help treat skin cancer, but no drugs have yet been approved. —Daniel Niemann, Los Angeles Times, 7 Oct. 2024

The field has developed a fairly solid understanding of how microRNA dysfunction contributes to disease. —Andrea Kasinski, The Conversation, 7 Oct. 2024

But subsequent work, including the discovery of another microRNA in 2000, proved that there are more than a thousand genes for different microRNAs in humans. —Patrick Smith, NBC News, 7 Oct. 2024

And abnormal microRNA can cause too much or too little of a protein, which can contribute to cancer. —Alexa Robles-Gil, Smithsonian Magazine, 7 Oct. 2024

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

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