斑马鱼胚胎第一次卵裂过程中胞内钙信号的研究

钙离子作为广泛存在的细胞内信使物质,在动物胚胎早期发育过程中扮演重要角色.为了研究钙离子在斑马鱼胚胎发育过程中的空间分布和浓度变化,采用Fluo-4和Indo-1作为钙离子指示剂,利用激光共聚焦和双波长荧光比例成像技术,对斑马鱼胚胎第一次卵裂过程中的钙信号进行了详细的跟踪观察.在第一次卵裂过程中,斑马鱼胚胎的动物极顶端首先出现高钙斑,然后在分裂沟部位出现高浓度的钙信号,这一信号在卵裂过程中持续存在.利用Indo-1双波长荧光比例成像对上述过程中钙离子的时空分布进行了定量测定,表明,胞内钙离子在卵裂开始之前是均匀分布的,随着分裂沟的出现,其附近区域的钙浓度显著升高,而胞内其他区域的钙浓度则保持不变.双波长荧光比例成像排除了荧光染料分布不均匀造成的干扰,为钙信号与胚胎分裂的密切关系提供了确凿的定量依据.

Intracellular Calcium Signaling During The First Cleavage of Zebrafish Embryo

Ca2 is a ubiquitous second messenger which plays a key role in early development of embryos.Ca2 probes(Fluo-4 or Indo-1) were injected into zebrafish eggs to detect the distribution of free Ca2 during their first cleavage using confocal microscopic or dual-wavelength ratiometric imaging.A high Ca2 zone was first observed in the animal pole right before the first cleavage,then it extended along the cleavage furrow and the Ca2 signal remained high in this region throughout the first cleavage.Intracellular Ca2 concentration(Ca]i) was measured via Indo-1 dual-wavelength system,and it was shown to be homogeneous within the whole embryo before the first cleavage.During the first cleavage,Ca]i increased significantly near the cleavage furrow,while it remained unchanged in other areas.As the dual-wavelength ratiometric imaging eliminates the artifacts due to indicator inhomogeneity,the results provided an unequivocal quantification for the Ca2 dynamics associated with the first cleavage of embryonic development.