The RNA binding protein Nab2 regulates level of RhoGEF Trio protein isoforms to govern mushroom body axon development Public

Abstract

Precise spatiotemporal regulation of gene expression is critical for normal brain development and function. Important neurodevelopmental events including neuronal differentiation, axon guidance, and synaptic plasticity are governed in part by post-transcriptional processing of mRNAs. Critically, these mechanisms rely on the actions of RNA binding proteins (RBPs) which associate with nascent mRNA molecules to regulate key aspects of RNA fate including stability, localization, and alternative splicing. Although these RBPs are generally ubiquitously expressed, loss of RBP function disproportionately results in significant neurological impairments, illustrating the enhanced reliance of the nervous system on post-transcriptional regulation of gene expression. Notably, loss of function mutations in the RBP ZC3H14 have been linked to a form of non-syndromic, autosomal recessive human intellectual disability (NS-ARID). To study the function of ZC3H14 in the nervous system, we utilize Drosophila Melanogaster as a model system. Drosophila have a well conserved ortholog of ZC3H14, known as nuclear polyadenosine RNA binding protein 2 (Nab2). The loss of Nab2 function in Drosophila causes behavioral impairments, short-term memory deficits, reduced survival, and disruptions in mushroom body morphology. Here, we demonstrate that Nab2 dictates Drosophila neurodevelopment through regulating splicing of the 5’ introns in the trio mRNA transcript, a gene shown to be conserved in humans. The Trio gene encodes a Rho guanine nucleotide exchange factor (RhoGEF) that controls axon development within the Drosophila nervous system. Specifically, these data identify that Nab2 controls cell-type specific expression of two opposing function Trio-GEF domains to rescue defects caused by the Nab2null mutation including mushroom body morphology, viability, and lifespan.

Table of Contents

Introduction....................................................................................................1 Methods........................................................................................................4

Drosophila Melanogaster Stocks and Genetics..................................................4

Drosophila Brain Dissection, Immunohistochemistry, Visualization, and Statistical Analysis .............................................................................................5

Viability and Lifespan Assay .....................................................................6 Locomotion Assay..................................................................................6 Statistical Analysis .................................................................................7

Results ........................................................................................................7 Overexpression of Trio-GEF2 in mushroom body lobes rescues a‘ lobe development

along with defasciculation in Nab2null mushroom bodies ....................................7 Figure 1..............................................................................................9 Overexpression of Trio-GEF2 rescues Nab2null defects in lifespan and viability.........9 Figure 2............................................................................................10

Discussion .................................................................................................10 Supplemental Figures ....................................................................................13 References .................................................................................................15

About this Honors Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Emory College
Department	Biology
Degree	B.S.
Submission	Honors Thesis
Language	English
Research Field	Biology, Neuroscience
Mot-clé	Drosophila Neurons RNA
Committee Chair / Thesis Advisor	Anita Corbett, Emory University Ken Moberg, Emory University
Committee Members	J. Alex Grizzell, Emory University Leila Reider, Emory University

Dernière modification

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	The RNA binding protein Nab2 regulates level of RhoGEF Trio protein isoforms to govern mushroom body axon development ()	2024-04-17 16:46:49 -0400	Press to Select an action Download

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions