Cytoplasmic RNA localization is a widespread mechanism for generating both embryonic and somatic cell polarity. Among vertebrates, Vg1 mRNA is a prominent example of a localized mRNA that plays a role in embryonic patterning. Vg1 mRNA encodes a peptide growth factor, and is localized during oogenesis to the vegetal cytoplasm of Xenopus oocytes. Restricted expression of Vg1 protein in the vegetal hemisphere of the egg is critical for correct patterning of the embryo, making localization of Vg1 mRNA an important model for understanding how maternal molecules are localized to influence pattern and polarity. The goal of this research project is to investigate how RNA molecules can be targeted to specific regions of the cell cytoplasm to generate cell polarity through spatially restricted protein expression. The foundation for this investigation has been laid by our progress studying the molecular interactions that govern this process. Our experiments have defined critical RNA-protein and protein-protein interactions leading to assembly of a transport-competent RNP complex and have uncovered distinct steps in the localization pathway. Our current proposal seeks to extend these findings by studying the dynamic transitions between these steps in the localization pathway. We will use a combination of in vivo and in vitro approaches to determine the molecular mechanisms responsible for localized expression of Vg1 mRNA.
Three specific aims are proposed:
In Aim I, we will characterize the dynamics and transport of the cytoplasmic Vg1 RNP complex, in Aim II, we will analyze the assembly and activity of RNP transport granules and in Aim III we will investigate the mechanisms that couple translational repression and RNA localization The proposed research is designed to reveal the mechanisms by which mRNA molecules are transported within cells to generate spatially restricted protein expression, and will provide insight into how developmental signals are spatially distributed in the vertebrate embryo. This work will impact issues related to human health such as birth defects, as well as neurological diseases that have been linked to defective RNA transport and localized protein synthesis.

Public Health Relevance

The goal of this research project is to elucidate the molecular mechanisms responsible for RNA localization and localized protein synthesis. These processes are critical for both embryonic development and neurological function. In particular, certain human diseases, including fragile X mental retardation syndrome and spinal muscular atrophy, have been linked to defects in RNA localization and localized protein synthesis.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Development - 2 Study Section (DEV2)
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Haynes, Susan R
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Brown University
Schools of Medicine
United States
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Jeschonek, Samantha P; Mowry, Kimberly L (2018) Whole-Mount Immunofluorescence for Visualizing Endogenous Protein and Injected RNA in Xenopus Oocytes. Cold Spring Harb Protoc 2018:pdb.prot097022
Neil, Christopher R; Mowry, Kimberly (2018) Fluorescence In Situ Hybridization of Cryosectioned Xenopus Oocytes. Cold Spring Harb Protoc 2018:pdb.prot097030
Ciocanel, Maria-Veronica; Kreiling, Jill A; Gagnon, James A et al. (2017) Analysis of Active Transport by Fluorescence Recovery after Photobleaching. Biophys J 112:1714-1725
Powrie, Erin A; Ciocanel, Veronica; Kreiling, Jill A et al. (2016) Using in vivo imaging to measure RNA mobility in Xenopus laevis oocytes. Methods 98:60-65
Gagnon, James A; Kreiling, Jill A; Powrie, Erin A et al. (2013) Directional transport is mediated by a Dynein-dependent step in an RNA localization pathway. PLoS Biol 11:e1001551
Pratt, Catherine A; Mowry, Kimberly L (2013) Taking a cellular road-trip: mRNA transport and anchoring. Curr Opin Cell Biol 25:99-106
Medioni, Caroline; Mowry, Kimberly; Besse, Florence (2012) Principles and roles of mRNA localization in animal development. Development 139:3263-76
Gagnon, James A; Mowry, Kimberly L (2011) Visualization of mRNA localization in Xenopus oocytes. Methods Mol Biol 714:71-82
Gagnon, James A; Mowry, Kimberly L (2011) Molecular motors: directing traffic during RNA localization. Crit Rev Biochem Mol Biol 46:229-39
Gagnon, James A; Mowry, Kimberly L (2010) Visualizing RNA localization in Xenopus oocytes. J Vis Exp :

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