miRNA

noun

ˌem-ˌī-ˌär-(ˌ)en-ˈā 

genetics

: microrna

A major part of this regulation is performed by microRNAs (miRNAs), small RNA molecules encoded by the genome that are not translated into proteins; rather, they control the expression of genes.

—Sebastien S. Hebert et al.

Examples of miRNA in a Sentence

Recent Examples on the Web

Typically the miRNA comes from a longer molecule, perhaps around 70 nucleotides long, known as pre-miRNA. —Philip Ball, Scientific American, 14 May 2024

Why would miRNA gene regulation work in this complicated way? —Philip Ball, Scientific American, 14 May 2024

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

The findings suggest that the specific serum miRNA profiles may serve as fingerprints for disease diagnosis. —Chao Yan, Scientific American, 17 June 2020

In 2017, Lönnerdal and his colleagues explored this question by exposing miRNA-containing exosomes from breast milk to acidic conditions that mimic those in the infant gut and observing how the packages fared2. —Tien Nguyen, Scientific American, 17 June 2020

So a single miRNA might match 20–50 mRNAs, Hicks says. —Tien Nguyen, Scientific American, 17 June 2020

Word History

First Known Use

2001, in the meaning defined above

Medical Definition

miRNA

noun

ˌem-ˌī-ˌär-ˌen-ˈā 

: microrna

MicroRNAs (miRNAs) are 20- to 22-nucleotide RNAs that regulate the function of eukaryotic messenger RNAs (mRNAs) and play important roles in development, cancer, stress responses, and viral infections.

—J. Ross Buchan et al., Science

Many of the noncoding RNAs, epitomized by the miRNA, have regulatory functions in normal cells. The aberrant expression of miRNA promotes tumorigenesis, metastasis, and other features of cancer.

—Frank J. Slack et al., The New England Journal of Medicine