Date of Award

Spring 2019

Degree Type

Thesis

Director of Thesis

Dr. Jeffery Twiss

First Reader

Dr. Priyanka Patel

Second Reader

Dr. Priyanka Patel

Abstract

Development of the nervous system follows a sequential pattern of gene expression in a precise spatiotemporal manner. There are a number of transcriptional and post-transcriptional mechanisms that control these gene networks. Of particular importance is the mechanisms that modulates mRNA stability, since expression of many neuronal genes is controlled by changes in rates of mRNA decay. HuD and KHSRP, two AU-rich elements (ARE) RNA binding proteins, exert opposite effects on mRNA stability, with HuD stabilizing and KHSRP destabilizing bound mRNA. Ongoing work from our lab has implicated interactions of HuD and KHSRP with target mRNAs in regulating rates of axon outgrowth and dendritic spine formation. HuD is highly expressed in early development, while KHSRP expression is low early and rises later as HuD levels fall. Thus, we are asked if this switch from HuD to KHSRP predominance signals the neuron to stop growing its axon and form a synapse, and if this “stop signal” correlates with a fall in axonal levels of target mRNAs shared by HuD and KHSRP. The ratio of HuD to KHSRP in developing neurons is critical for controlling Gap-43and Cdc42 mRNA levels, whose protein levels are critical for axon growth. The creation of artificial synapses utilizing a microfluidic system by transfecting HEK293 cells with Neuroligin (NL1) and coculturing these with neurons will allow for the determination of whether axonal levels of HuD/KHSRP target mRNAs are altered over the course of synaptogenesis. Uncovering the precise timing for the switch HuD:KHSRP stoichiometry in developing neurons will bring new knowledge for how mRNA-protein interactions impact normal and pathological brain development.

First Page

1

Last Page

35

Rights

© 2019, Devon Elizabeth Cassidy

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