Worms lacking an RNAi enzyme have enlarged oocyte nuclei.
Bass/AAAS
RNA interference (RNAi) is an ancient mechanism for executing the epigenetic phenomenon called gene silencing. It has quickly become a standard way to figure out what a gene is doing, even though not much is known about how it works.
When Thomas Tuschl and Phillip Zamore reported last year that, in vitro, RNAi involves cleavage into short pieces of both a double-stranded RNA and subsequently the rest of the target mRNA, Brenda Bass immediately had a hunch that the responsible enzyme was one she had encountered a decade ago. She and her colleague Scott Knight (University of Utah, Salt Lake City, UT) have now verified that hunch. They have shown not only that the enzyme (known appropriately as Dicer) is required for RNAi, but that it is essential for normal development.
With the help of...