miRNA
Meaning of miRNA: miRNA molecules are short strands of RNA that bind messenger RNA to block protein production, providing cells a way to fine-tune gene activity.
Definition of miRNA
miRNA, or microRNA, is a type of small RNA molecule found within cells and circulating in blood, considerably shorter than messenger RNA or the RNA used to build ribosomes. Unlike messenger RNA, miRNA does not carry instructions for building a protein.
Instead, a miRNA molecule binds to a specific messenger RNA, generally preventing that messenger RNA from being used to make its corresponding protein, or causing it to be broken down. Through this mechanism, miRNAs act as fine tuning regulators of gene activity, helping control how much of a given protein a cell produces at a given time.
Because miRNAs help regulate so many cellular processes, changes in which miRNAs a cell produces, and in what amount, have been linked to the development of certain diseases, including some cancers, and measuring circulating miRNA levels in blood is an area of ongoing research interest as a possible diagnostic tool.
Also known as
Used in a sentence
Laboratory analysis measured circulating miRNA levels as part of the research study.
Good to know
A single miRNA molecule can regulate many different messenger RNAs at once, so its overall effect on a cell depends on the full set of genes it targets rather than any single target alone.
Word origin
Where “miRNA” comes from
Formed from Greek mikros, meaning small, combined with RNA, an abbreviation for ribonucleic acid.