Look deep inside our cells, and you'll find that each has an identical genome--a complete set of genes that provides the instructions for our cells' form and function. But if each blueprint is identical, why does an eye cell look and act differently than a skin cell or a brain cell? How does a stem cell--the raw material with which our organ and tissue cells are made--know what to become? In a study published online on July 6, 2020 in Nature Genetics (https://www.nature.com/articles/s41588-020-0662-x), University of Colorado-Boulder (CU Boulder) researchers come one step closer to answering that fundamental question, concluding that the molecular messenger RNA (ribonucleic acid) plays an indispensable role in cell differentiation, serving as a bridge between our genes and the so-called "epigenetic" machinery that turns them on and off. When that bridge is missing or flawed, the researchers report in their article, a stem cell on the path to becoming a heart cell never learns how to beat. The article is titled “RNA Is Essential for PRC2 Chromatin Occupancy and Function in Human Pluripotent Stem Cells.” The paper comes at a time when pharmaceutical companies are taking unprecedented interest in RNA. And, while the research is young, it could ultimately inform development of new RNA-targeted therapies, from cancer treatments to therapies for cardiac abnormalities. "All genes are not expressed all the time in all cells. Instead, each tissue type has its own epigenetic program that determines which genes get turned on or off at any moment," said co-senior author Thomas Cech (photo) (https://en.wikipedia.org/wiki/Thomas_Cech), PhD, a Nobel laureate and Distinguished Professor of Biochemistry. "We determined in great detail that RNA is a master regulator of this epigenetic silencing and that in the absence of RNA, this system cannot work. It is critical for life."Login Or Register To Read Full Story