The piRNA pathway was thought to be most active in the reproductive organs of animals, but researchers, including doctoral student in Molecular Biology, Cell Biology, and Biochemistry, Brian Jones, have discovered in the common fruit fly that the pathway also operates in a non-reproductive body tissue, playing a vital role in maintaining health and lifespan.
Humans and other animals carry rogue sequences of DNA in their genomes called transposable elements (TEs). To prevent passing TEs to their offspring, they employ the piRNA pathway in their reproductive organs to block the elements from being active in their sperm and eggs. With a new study in flies, Brown University biologists are the first to show that the anti-TE activity of the piRNA pathway also operates in a normal non-reproductive body tissue, the fly fat body, and that it helps to sustain the life of the animal.
“It’s required for normal health and longevity,” said Dr. Stephen Helfand, senior author of the study in Nature Communications and a professor of biology at Brown University.
Most previous reports of piRNA at work outside of reproductive organs were in cancer or stem cells, with one study suggesting it may also be present in a subset of adult fly neurons, but no one had ever measured its consequences in normal health and aging.
In experiments led by Jones, the research team tracked several components of the pathway, such as the presence of piRNAs and the expression of associated “piwi” and “flamenco” genes, in the fat body tissue of flies. The fat body is akin to adipose and liver tissues in mammals and also contributes to flies’ immune systems.
Read more of David Orenstein's story about RNA pathways.