Eif4a3 is a component of an RNA binding exon junction complex (EJC) implicated in neural development and disease. The EJC is composed of Eif4a3, Magoh, and Rbm8a. EIF4A3 mutations are associated with intellectual disability and hypomorphic mutations cause Richieri-Costa-Pereira syndrome (RCPS), a craniofacial developmental syndrome accompanied by microcephaly and cognitive disability. Yet, the underlying mechanisms of EIF4A3-mediated neurodevelopmental pathologies remain largely unknown. This renewal proposal aims to address this gap by defining requirements for Eif4a3 in two critical processes of cortical development: neurogenesis and neuronal maturation. In the prior funding period of this grant, we discovered that Magoh mutant progenitors exhibit prolonged mitosis, which directly alters fates of newborn progeny. We generated mouse models for all 3 core EJC components. Using these mice we discovered that EJC haploinsufficiency in progenitors results in strikingly similar defects in neurogenesis, microcephaly, and dysregulation of common transcripts. Our genetic and genomic discoveries indicate that Eif4a3 may control neural progenitors and neurogenesis via the EJC. In contrast, our recent unpublished work indicate that, Eif4a3 may have EJC-independent functions in neurons. Further, we implicate microtubule regulation in these non- canonical mechanisms. Based on our findings we hypothesize that Eif4a3 employs canonical RNA regulatory and non-canonical microtubule mechanisms to differentially control progenitors and neurons during brain development. This proposal will test this hypothesis by exploiting unique mouse models and human iPSC models, as well as live imaging assays developed in our lab. We will: (1) define cellular and molecular mechanisms by which Eif4a3 influences neurogenesis, (2) determine developmental and molecular requirements of Eif4a3 in neuronal maturation, and (3) determine the cellular and molecular impact of EIF4A3 mutations in human cells. Successfully completed, we will have significantly advanced our understanding of how Eif4a3 controls critical stages of cortical development, via both canonical and non-canonical mechanisms. We anticipate the discoveries resulting from this proposal will be broadly impactful for understanding cortical development and the etiology of neurodevelopmental disease.

Public Health Relevance

This project will advance our understanding of neural progenitor fate specification and neuronal maturation during brain development. It will further an understanding of the etiology of neurodevelopmental disorders, including intellectual disability, microcephaly, and autism. Therefore, this study may eventually help in the development of diagnostic and therapeutic options for broad neurological disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS083897-06
Application #
9839694
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Riddle, Robert D
Project Start
2013-06-01
Project End
2024-05-31
Budget Start
2019-09-15
Budget End
2020-05-31
Support Year
6
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Duke University
Department
Genetics
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Lennox, Ashley L; Mao, Hanqian; Silver, Debra L (2018) RNA on the brain: emerging layers of post-transcriptional regulation in cerebral cortex development. Wiley Interdiscip Rev Dev Biol 7:
Mitchell, Caitlyn; Silver, Debra L (2018) Enhancing our brains: Genomic mechanisms underlying cortical evolution. Semin Cell Dev Biol 76:23-32
Pilaz, Louis-Jan; Silver, Debra L (2017) Moving messages in the developing brain-emerging roles for mRNA transport and local translation in neural stem cells. FEBS Lett 591:1526-1539
Mao, Hanqian; Brown, Hannah E; Silver, Debra L (2017) Mouse models of Casc3 reveal developmental functions distinct from other components of the exon junction complex. RNA 23:23-31
Miller, Emily E; Kobayashi, Gerson S; Musso, Camila M et al. (2017) EIF4A3 deficient human iPSCs and mouse models demonstrate neural crest defects that underlie Richieri-Costa-Pereira syndrome. Hum Mol Genet 26:2177-2191
Pilaz, Louis-Jan; Lennox, Ashley L; Rouanet, Jeremy P et al. (2016) Dynamic mRNA Transport and Local Translation in Radial Glial Progenitors of the Developing Brain. Curr Biol 26:3383-3392
Pilaz, Louis-Jan; McMahon, John J; Miller, Emily E et al. (2016) Prolonged Mitosis of Neural Progenitors Alters Cell Fate in the Developing Brain. Neuron 89:83-99
Silver, Debra L (2016) Genomic divergence and brain evolution: How regulatory DNA influences development of the cerebral cortex. Bioessays 38:162-71
Mao, Hanqian; McMahon, John J; Tsai, Yi-Hsuan et al. (2016) Haploinsufficiency for Core Exon Junction Complex Components Disrupts Embryonic Neurogenesis and Causes p53-Mediated Microcephaly. PLoS Genet 12:e1006282
McMahon, J J; Miller, E E; Silver, D L (2016) The exon junction complex in neural development and neurodevelopmental disease. Int J Dev Neurosci 55:117-123

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