New insight into the process that converts
experiences into stable long-term memories has
been uncovered by neurobiologists from the
University of California, Irvine and the University of
Queensland.
The team, led by Timothy Bredy, UCI associate
professor of neurobiology & behavior, discovered
that chemical modifications that add methyl groups
to RNA, a process known as methylation, could
strengthen memory formation. Results appear June
22 in the Journal of Neuroscience.
The modification of RNA by methylation can affect
how it functions within a cell. When the researchers
reduced the brain levels of an enzyme that removes
methyl groups from RNA, the result was a boost in
memory formation.
"By genetically silencing an enzyme in a specific
region of the brain involved in memory and adaptive
behavior, we saw much better memory recall in
mice," said Jocelyn Widagdo, postdoctoral fellow
and co-lead author of the study from the
Queensland Brain Institute in Australia.
To investigate the possible role of RNA methylation
in the formation of new memories, Bredy and his
colleagues searched the entire genome for
methylated RNA in brain tissue from mice recently
trained on a learning task. They found widespread
changes in a recently identified epigenetic mark,
N6-methyladenosine (m6A), on RNA when new
memories were formed. Epigenetic processes are
believed to be the molecular link between our genes
and the environment, such as during learning.
"Our findings show that memory processing is not
just influenced by epigenetic control over our DNA
but also occur at the level of RNA, variations in
which act like a messenger in our cells," said Bredy.
"m6A shows enormous potential because the
process can rapidly fine-tune our gene function and
expression, which is often impaired in a variety of
neurological disorders."
According to the researchers, a next step would be
for them to determine what happens to the process
during other forms of learning, and whether the
network is disrupted in memory-related disorders
such as post-traumatic stress disorder or phobia
