CHEVY CHASE, Md., June 7 (UPI) -- Two groups of U.S. researchers say they have unearthed a whole new class of small RNA molecules manufactured by the mammalian genome.
The scientists say the RNA molecules, which might have a role in the production of sperm, expand the growing range of functions attributed to non-protein-coding RNA.
Researchers are already familiar with microRNAs, 21-23-nucleotide fragments that can silence genes and act by binding to a group of Argonaute proteins. It was also known a subgroup of Argonaute proteins, known as the Piwi family, is important in the production of germ cells.
The study by the two teams -- led by Thomas Tuschl of the Maryland-headquartered Howard Hughes Medical Institute and Gregory Hannon of the Cold Spring Harbor Laboratory -- show certain members of the Piwi family in mice actually bind to a previously unknown class of slightly longer RNAs, somewhere between 26-31 nucleotides in length and abundant in developing sperm.
Those Piwi-interacting RNAs, or piRNAs, are common in the mouse genome and lie in clusters, suggesting they are actually cut from longer RNA transcripts. Similar piRNAs are generated from the human genome.
The linked studies appear in the journal Nature.