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Principal Investigator: William Horne
Contact Information: Email: wah27@cornell.edu - Phone: 607-253-4145
Sponsor: NSF
Grant Number: IOS-0719242
Title: Collaborative Research: Calcium Channel Beta Subunits in Early Development
Annual Direct Cost: $62,716
Project Period: 08/15/07-07/31/10
DESCRIPTION (provided by applicant): Intellectual merit: This proposal focuses on the Ca2+ channel ß4 subunit, a five domain modular protein that for over a decade has been thought to function solely as a Ca2+ channel auxiliary subunit. Recently, however, it has become evident that ß4 subunits play multiple roles in cells through functions that can be linked to interactions of cytosolic and nuclear proteins with specific ß subunit modules. While exploring the potential importance of ß4 subunits in zebrafish development, our preliminary experiments revealed an unexpected role for the Ca2+ channel ß4 subunit in epiboly, a morphogenetic movement in which the embryonic cell mass spreads over the surface of the yolk. Single-cell embryos injected with a ß4 antisense morpholino complete initial cell cleavages normally through the 1000-cell stage, but most embryos subsequently fail to initiate epiboly. The embryos develop an unusual pattern of cell death in a ring encompassing the late blastula. This effect in pre-gastrula development is especially surprising given that there is no evidence for voltage-gated Ca2+ channel function this early in development. Based on further preliminary experiments described herein, the central hypothesis of this proposal is that the ß4 subunit, via its modular protein-protein interactions, coordinates cytoskeletal functions in the yolk syncytium (YSL) that are essential for epiboly. The goals of this study are to determine the mechanism(s) by which the ß4 subunit influences the development of the early embryo: 1) Does the ß4 subunit interact with cytoskeletal machinery in the YSL, as proposed? 2) Does the ß4 subunit affect cell division, survival or differentiation of embryonic cells? More specifically, we will identify the individual domain(s) of the ß4 subunit that are required for epiboly and morphogenesis in the early embryo. Broader impacts: A broader impact of these studies is to provide training and collaborative opportunities for graduate and undergraduate students on two campuses, utilizing video conferencing. The project will make possible summer internship opportunities for minority undergraduate students enrolled at Colorado State University-Pueblo, an affiliated Hispanic Serving Institution. The systematic evaluation of morpholino-induced phenotypes by cell labeling and injection rescue assays provides a logical entry point for students to learn experimental design, evaluation and troubleshooting. The planned experiments should enable students to generate data worthy of publication and presentation at conferences.
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