Extensive apoptosis and abnormal morphogenesis in pro-caspase-3 transgenic zebrafish during development
Extensive apoptosis and abnormal morphogenesis in pro-caspase-3 transgenic zebrafish during development
复制标题
DOI：
10.1242/jeb.012690
复制
发表时间：
2008-06
影响因子：
2.8
通讯作者：
M. Yamashita;Nanami Mizusawa;M. Hojo;Takeshi Yabu
中科院分区：
文献类型：
--
作者：
M. Yamashita;Nanami Mizusawa;M. Hojo;Takeshi Yabu
摘要 促凋亡 caspase-3 基因已被证明在脊椎动物细胞凋亡（程序性细胞死亡）的执行中具有关键功能。然而，caspase-3 在发育过程中形态发生中的核心作用仍不清楚。在这项研究中，产生了过度表达全长 caspase-3 前体的转基因斑马鱼，以确定 caspase 基因对脊椎动物形态发生和胁迫耐受性的影响。全长 pro-caspase-3 cDNA 的增强表达诱导了转基因胚胎中极高水平的 caspase 活性和广泛的细胞凋亡，并且转基因系中 33-46% 的 F2 胚胎表现出某种形式的形态异常。 Pro-caspase-3 转基因斑马鱼在眼睛、脊索、心脏和卵黄囊中表现出异常的形态发生，这表明 pro-caspase-3 的增强加工会在发育过程中经历形态发生的特定靶组织中引发显着的凋亡反应。转基因鱼的眼睛尺寸缩小，视网膜（包括感光细胞层）出现退化，但色素沉着和晶状体形成不受影响。此外，在 pro-caspase-3 转基因胚胎中还发现了由于心跳减弱和循环减少而导致的心力衰竭。转基因胚胎对应激条件明显敏感，例如 2 或 5 mJ cm-2 的紫外线照射。另一方面，通过向胚胎注射反义吗啉寡核苷酸，导致 caspase-3 缺陷，从而抑制细胞凋亡并增强紫外线照射后的应激耐受性。因此，caspase-3介导的促凋亡信号通路及其激活在斑马鱼胚胎发生过程中诱导细胞凋亡和应激耐受中发挥着关键作用。
SUMMARY The pro-apoptotic caspase-3 gene has been shown to have key functions in the execution of apoptosis (programmed cell death) in vertebrate cells. However, the central role of caspase-3 in morphogenesis during development remains unclear. In this study, transgenic zebrafish that overexpress full-length pro-caspase-3 were generated to determine the effects of caspase genes on vertebrate morphogenesis and stress tolerance. The enhanced expression of the full-length pro-caspase-3 cDNA induced extremely high levels of caspase activity and extensive apoptosis in the transgenic embryos, and 33–46% of F2 embyos in the transgenic lines exhibited some form of morphological abnormality. Pro-caspase-3 transgenic zebrafish exhibited abnormal morphogenesis in the eyes, notochord, heart and yolk sac, suggesting that enhanced processing of pro-caspase-3 triggers significant apoptotic responses in the specific target tissues that are undergoing morphogenesis during development. The transgenic fish had reduced eye size and showed degeneration of the retina, including the photoreceptor cell layers, whereas pigmentation and lens formation were not affected. In addition, heart failure due to a weakened heartbeat and reduced circulation was noted in the pro-caspase-3 transgenic embryos. The transgenic embryos were markedly sensitive to stress conditions, such as UV irradiation at 2 or 5 mJ cm–2. On the other hand, caspase-3 deficiency through injection of antisense morpholino oligo into embryos repressed apoptosis and enhanced stress tolerance after UV irradiation. Therefore, the caspase-3-mediated pro-apoptotic signalling pathway and its activation play critical roles in the induction of apoptosis and stress tolerance during zebrafish embryogenesis.