Reliable gene silencing is vital to the health of an organism.
Improperly activated genes can and do lead to cancer, for
example. Gene silencing is also thought to protect the genome
from viruses and other potentially damaging entities, thus
preserving genetic integrity. In a new study, researchers at The
Wistar Institute and colleagues have identified an important new
global mechanism for this essential gene silencing, or gene
repression. A report on the findings appears in the April 15
issue of Genes & Development. "We've discovered what looks to be
an evolutionarily ancient mechanism for broadly repressing and
protecting the genome," says Shelley L. Berger, Ph.D., the
Hilary Koprowski Professor at The Wistar Institute and senior
author on the study. "We believe it to be the first identified
mechanism of its kind." The new mechanism centers on histones,
relatively small proteins around which DNA is coiled to create
structures called nucleosomes. Compact strings of nucleosomes,
then, form into chromatin, the