Towards determining the role of neuronal processing bodies in regulating the translation of constituent mRNAs

Abstract

Neurons undergo dynamic changes as intercellular connections are created or modified, a phenomenon known as synaptic plasticity. This plasticity largely depends on the transport and local translation of messenger RNAs (mRNAs) into proteins. Strict control of what proteins are synthesized and when and where translation occurs is therefore crucial to neuron signaling. Despite recent advances in the field, there is still much unknown about the mechanisms by which neurons control translation. Some researchers believe that processing bodies (p-bodies) – or liquid-like condensates containing translationally repressed mRNAs and proteins involved in RNA decay – may play a role in RNA metabolism within neurons. However, because the role of p-bodies has been characterized in a limited number of cell types and physiological contexts, their functions in neurons and synaptic plasticity remain poorly understood. Based on their functions in other cells, we believe that these condensates regulate translation by storing translationally silenced mRNAs until synaptic activation prompts protein synthesis. In this thesis, we work towards determining whether p-bodies play an important role in the regulation of translation in neurons by knocking the condensates down, with the goal of later assessing effects on protein abundance. To do so, we identified essential proteins in p-bodies that abrogate the formation of p-bodies upon knockdown using short hairpin RNAs. To differentiate p-body effects from the functions of individual protein knockdown, we designed artificial proteins that could rescue p-bodies following knockdown and tested them in HEK cells. This work is foundational for future experiments studying the role of neuronal p-bodies in mRNA metabolism. Furthermore, because the dysregulation of translation has been implicated in neurodegeneration, this could offer a new approach to better understanding the onset and progression of neurological disorders and diseases.