title: Suppression of the endoplasmic reticulum calcium pump during zebrafish gastrulation affects left-right asymmetry of the heart and brain.
abstract: Vertebrate embryos generate striking Ca(2+) patterns, which are unique regulators of dynamic developmental events. In the present study, we used zebrafish embryos as a model system to examine the developmental roles of Ca(2+) during gastrulation. We found that gastrula stage embryos maintain a distinct pattern of cytosolic Ca(2+) along the dorsal-ventral axis, with higher Ca(2+) concentrations in the ventral margin and lower Ca(2+) concentrations in the dorsal margin and dorsal forerunner cells. Suppression of the endoplasmic reticulum Ca(2+) pump with 0.5 microM thapsigargin elevates cytosolic Ca(2+) in all embryonic regions and induces a randomization of laterality in the heart and brain. Affected hearts, visualized in living embryos by a subtractive imaging technique, displayed either a reversal or loss of left-right asymmetry. Brain defects include a left-right reversal of pitx2 expression in the dorsal diencephalon and a left-right reversal of the prominent habenular nucleus in the brain. Embryos are sensitive to inhibition of the endoplasmic reticulum Ca(2+) pump during early and mid gastrulation and lose their sensitivity during late gastrulation and early segmentation. Suppression of the endoplasmic reticulum Ca(2+) pump during gastrulation inhibits expression of no tail (ntl) and left-right dynein related (lrdr) in the dorsal forerunner cells and affects development of Kupffer's vesicle, a ciliated organ that generates a counter-clockwise flow of fluid. Previous studies have shown that Ca(2+) plays a role in Kupffer's vesicle function, influencing ciliary motility and translating the vesicle's counter-clockwise flow into asymmetric patterns of gene expression. The present results suggest that Ca(2+) plays an additional role in the formation of Kupffer's vesicle.
authors: Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Box G-L127, 185 Meeting Street, Providence, RI 02912, USA.
authors: Jill A
authors: JA
authors: Kreiling
authors: Zaneta L
authors: ZL
authors: Balantac
authors: Andrew R
authors: AR
authors: Crawford
authors: Yuexin
authors: Y
authors: Ren
authors: Jamal
authors: J
authors: Toure
authors: Sigalit
authors: S
authors: Zchut
authors: Lazaros
authors: L
authors: Kochilas
authors: Robbert
authors: R
authors: Creton
mesh_terms: D000818:Animals; D019521:Body Patterning; D001921:Brain / Q000196:embryology*; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D004398:Dyneins / Q000096:biosynthesis* / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005326:Fetal Proteins; D005775:Gastrula / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000196:embryology*; D017403:In Situ Hybridization; D008954:Models, Biological; D019831:Sodium-Calcium Exchanger / Q000096:biosynthesis* / Q000502:physiology; D020825:T-Box Domain Proteins / Q000096:biosynthesis* / Q000502:physiology; D019284:Thapsigargin / Q000494:pharmacology; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000096:biosynthesis* / Q000502:physiology; D000098908:Brachyury Protein
chemical_list: D002118:Calcium; D004398:Dyneins; D005326:Fetal Proteins; D019831:Sodium-Calcium Exchanger; D020825:T-Box Domain Proteins; D019284:Thapsigargin; D029961:Zebrafish Proteins; D000098908:Brachyury Protein