Visualization, characterization and modulation of calcium signaling during the development of slow muscle cells in intact zebrafish embryos
|Authors||Cheung, Chris Y.
Webb, Sarah E.
Love, Donald R.
Miller, Andrew L.
|Source||The International journal of developmental biology, v. 55, (2), 2011, p. 153-174|
|Summary||Intact zebrafish embryos were used as an in vivo animal model to investigate the role of Ca(2+) signaling during the differentiation of slow muscle cells (SMCs) within forming skeletal muscle. Transgenic zebrafish were generated using an alpha-actin promoter that targeted apoaequorin expression specifically to muscle cells. Two distinct Ca(2+) signaling periods (CSPs) were visualized in the developing SMCs: between similar to 17.5-19.5 hours post-fertilization (hpf) and after similar to 23 hpf, separated by a similar to 3.5 h Ca(2+) signaling quiet period. Further spatial characterization of these Ca(2+) signals using confocal fluorescent microscopy and calcium green-1 dextran as a reporter, indicated that the earlier CSP displayed distinct nuclear and cytoplasmic components, whereas the later CSP was predominantly cytoplasmic. Both CSPs consisted of a series of oscillating Ca(2+) waves generated at distinct frequencies, while the earlier CSP also displayed a slow rise then fall in the Ca(2+) baseline-level. Imaging of cyclopamine- and forskolin-treated wild-type, or smo(-/-) mutant embryos, where SMCs do not form, confirmed the specific cell population generating the signals. Treating embryos with antagonists indicated that both IP(3)Rs and RyRs are responsible for generating the temporal characteristics of the Ca(2+) signaling signature, and that the latter plays a necessary role in SMC differentiation and subsequent myotome patterning. Together, these data support and extend the proposition that specific spatiotemporal patterns of spontaneous Ca(2+) signals might be used for different as well as combinatorial regulation of both nuclear and cytosolic signal transduction cascades, resulting in myofibrillogenesis in SMCs as well as myotome patterning.|
|Rights||© Copyright 2011 UBC Press.|
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