New roles for calcium channel beta subunits in early zebrafish development
Date
2008
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Abstract
Voltage-gated calcium channels are present on pre-synaptic terminals and at neuromuscular junctions in the adult. In embryos, the channel is primarily expressed in the developing heart. The auxiliary β subunit is responsible for trafficking the pore-forming α subunit to the membrane, and regulating the calcium channel kinetics. In non-canonical roles, the β subunit regulates gene silencing, vesicle docking, and calcium release from pancreatic cells. We report here the cloning and expression of two zebrafish β2 genes and two β4 genes. Morpholino inhibition of the β4 subunit slowed or blocked the morphogenetic movements of gastrulation, causing the blastoderm to retract and the embryos to assume dorsalized phenotypes. The nuclei of the extra-embryonic yolk syncytial layer (YSL) contained extra centrosomes, which led to formation of abnormal mitotic spindle. Microtubule arrays in the yolk were disrupted or absent. In 48 hpf embryos, the axis of the embryo was expanded mediolaterally and shorter anteroposteriorly. Gastrulation defects were present as early as shield formation. These data combined support the hypothesis for a novel role of the β4 subunit in early zebrafish development.
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Subject
calcium
development
epiboly
mitosis
patterning
zebrafish
neurosciences