Small molecules set up security system to defend the genome

"Thousands of short RNA molecules with diverse genetic sequences serve as security guards to identify and silence attempts to invade the genome, such as DNA inserted by viruses or parasitic elements known as transposons.

These diverse, small RNA molecules, known as Piwi-interacting RNAs (piRNAs) are produced by various animals, from insects and worms to mammals like mice and humans. In a new study published February 2 in the journal Science, researchers from the University of Chicago describe how piRNAs find foreign genetic sequences to silence them. They also show how endogenous or "self" genes that properly belong in the genome identify themselves to avoid this additional scrutiny.

"Nearly every animal has these small RNAs, and they use them as a guide to look for target sequences and silence them," said Heng-Chi Lee, PhD, assistant professor of molecular genetics and cell biology at UChicago and senior author of the new study. "Until now though, it was rather mysterious what their function was, and why there are so many with such diverse genetic sequences..." | Learn More >>