Protein synthesis in the extensions of nerve cells, called dendrites, underlies long-term memory formation in the brain, among other functions. “Thousands of messenger RNAs reside in dendrites, yet the dynamics of how multiple dendrite messenger RNAs translate into their final proteins remain elusive,” says James Eberwine, PhD, professor of Pharmacology, Perelman School of Medicine at the University of Pennsylvania, and co-director of the Penn Genome Frontiers Institute.
Dendrites, which branch from the cell body of the neuron, play a key role in the communication between cells of the nervous system, allowing for many neurons to connect with each other. Dendrites detect the electrical and chemical signals transmitted to the neuron by the axons of other neurons. The synapse is the neuronal structure where this chemical connection is formed, and investigators surmise that it is here where learning and memory occur.
These structural and chemical changes – called synaptic plasticity -- require rapid, new synthesis of proteins. Cells may use different rates of translation in different types of mRNA to produce the right amounts and ratios of required proteins.
Knowing how proteins are made to order – as it were - at the synapse can help researchers better understand how memories are made. Nevertheless, the role of this “local” environment in regulating which messenger RNAs are translated into proteins in a neuron’s periphery is still a mystery.
Eberwine, first author Tae Kyung Kim, PhD, a postdoc in the Eberwine lab, and colleagues including Jai Yoon Sul, PhD, assistant professor in Pharmacology, showed that protein translation of two dendrite mRNAs is complex in space and time, as reported online in Cell Reports this week.
“We needed to look at more than one RNA at the same time to get a better handle on real- world processes, and this is the first study to do that in a live neuron,” Eberwine explains.
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