Since the sequencing of the human and
other genomes in the 1990s, it has been recognized that large sections of the
genome did not appear to be coding for genes that produced protein products.
This observation earned these regions the unfortunate title of “junk DNA”.
Recent studies, however have put to rest the notion that organisms cart around
a load of useless DNA sequences. It is now evident that these megabases of DNA
are essential for controlling the flow of genetic information, and that these
regions carry networks of epigenetic and genetic regulatory genes coordinating
this activity.
A slew of papers published simultaneously
in Nature and Science have revealed the complexity of the genome’s regulatory
networks. Starting in 2003, the ENCODE
project revealed that 76% of the genome is
transcribed into RNA molecules that do not translate into proteins. These RNAs
are involved gene regulation by combining with and blocked specific messenger
RNA molecules. These regulatory RNA molecules travel to different sites within
the cell where they exert their controlling influences.
In addition, the researchers identified
genes that code for regulatory proteins that influence gene activity by binding
to specific sites within the DNA. These proteins frequently exert their
regulatory power by binding to the histones, a class of DNA-associated proteins
that form part of the epigenome.
While these studies are building an
understanding genetic regulation and its complexities in humans, they are also
aiding in our analysis of disease processes. The investigators identified many
genetic regulatory variants related to diseases such as diabetes, bipolar
disorder, Parkinson’s disease and lupus. The researchers further state that
they have uncovered regulatory DNA variation in a variety of pathological
states, revealing important insights into the origins of these conditions.
The understanding genomic and epigenomic
regulatory networks in human disease represents a new paradigm and a basis for
the development of radical new drug therapies.
A more detailed look at the role of epigenetics in clinical medicine and epigenetics in drug
discovery is the subject of a recent Kalorama report, Epigenetics, a complete market research survey of the nascent epigenetic industry authored by K. John Morrow, Jr. PhD.
