hecate, a zebrafish maternal effect gene, affects dorsal organizer induction and intracellular calcium transient frequency
hecate, a zebrafish maternal effect gene, affects dorsal organizer induction and intracellular calcium transient frequency
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DOI：
10.1016/j.ydbio.2005.07.031
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发表时间：
2005-10-15
影响因子：
2.7
通讯作者：
Pelegri, F
中科院分区：
文献类型：
--
作者：
Gingerich, JL;Westfall, TA;Pelegri, F
斑马鱼hecate基因中的母体效应突变导致胚胎在背前部结构形成方面存在缺陷，并改变了钙释放。hecate突变体胚胎缺乏β-连环蛋白的核积累，并且具有对背侧组织者特异性的基因表达降低。我们发现，hecate突变体胚胎表现出近10倍的细胞内Ca 2+瞬变的频率增加，通常存在于包膜层在囊胚阶段。Ca 2+释放的抑制导致突变体胚胎中背侧基因的异位表达，这表明Ca 2+瞬变在介导背侧基因表达中是重要的。Ca 2+释放的抑制也导致在包被层中的背特异性基因以β-连环蛋白独立的方式表达，这表明在该细胞层中Ca 2+瞬变的额外功能。突变体表型可以通过激活Wnt/β-连环蛋白信号传导的因子的表达来逆转，这表明Wnt/β-连环蛋白途径，至少在被外源Wnt配体激活时，在hec突变体胚胎中是完整的。我们的研究结果是一致的hecate基因在调节的Ca 2+释放过程中的卵裂阶段，这反过来又影响背侧基因的表达在边缘细胞沿着背腹轴和在包膜层的作用。(C)2005年爱思唯尔公司All rights reserved.
A zebrafish maternal effect mutation, in the gene hecate, results in embryos that have defects in the formation of dorsoanterior structures and altered calcium release. hecate mutant embryos lack nuclear accumulation of beta-catenin and have reduced expression of genes specific to the dorsal organizer. We found that hecate mutant embryos exhibit a nearly 10-fold increase in the frequency of intracellular Ca2+ transients normally present in the enveloping layer during the blastula stages. Inhibition of Ca2+ release leads to ectopic expression of dorsal genes in mutant embryos suggesting that Ca2+ transients are important in mediating dorsal gene expression. Inhibition of Ca2+ release also results in the expression of dorsal-specific genes in the enveloping layer in a beta-catenin-independent manner, which suggests an additional function for the Ca2+ transients in this cellular layer. The mutant phenotype can be reversed by the expression of factors that activate Wnt/beta-catenin signaling, suggesting that the Wnt/beta-catenin pathway, at least as activated by an exogenous Wnt ligand, is intact in hec mutant embryos. Our results are consistent with a role for the hecate gene in the regulation of Ca2+ release during the cleavage stages, which in turn influences dorsal gene expression in both marginal cells along the dorsoventral axis and in the enveloping layer. (C) 2005 Elsevier Inc. All rights reserved.