Chun Chang Zoon, Tsai H J, Chen Thomas T
Department of Molecular and Cell Biology, University of Connecticut, Storrs, 06269-3125, USA.
Mol Reprod Dev. 2006 Sep;73(9):1112-21. doi: 10.1002/mrd.20473.
E-peptide of the pro-insulin-like growth factor (pro-IGF)-I is produced by proteolytic cleavage of the pro-hormone in post-translational processing. Introduction of a transgene encoding a secreted form of rtEa4- or hEb-peptide into newly fertilized zebrafish (Danio rerio) eggs by electroporation or microinjection resulted in embryos with abnormal cardiovascular features and reduced red blood cells and vasculature. Two different phenocopies of heart developmental defects were observed: (i) Group I embryos exhibited heart development arrested at the heart muscle stage and (ii) group II embryos exhibited heart development arrested at the heart tube stage. Both groups of embryos also exhibited reduction of red blood cells and vasculature. The mRNA levels of genes essential for heart development (GATA 5 and NKX2.5), hematopoiesis (GATA 1 and GATA 2), and vasculogenesis (VEGF) in normal and defective embryos were determined by quantitative real-time RT-PCR at 36 hr post-fertilization (hpf). Significant reduction of GATA 5, NKX2.5, GATA 1, GATA 2, and VEGF mRNA levels was observed in both groups of defective embryos. These results suggest that overexpression of rtEa4 or hEb transgene in zebrafish embryos disrupts heart development, hematopoiesis, and vasculogenesis by reducing the levels of GATA 5, NKX2.5, GATA 1, GATA 2, and VEGF mRNA.
胰岛素样生长因子（pro-IGF）-I的E肽是在翻译后加工过程中通过激素原的蛋白水解切割产生的。通过电穿孔或显微注射将编码分泌形式的rtEa4或hEb肽的转基因导入新受精的斑马鱼（Danio rerio）卵中，导致胚胎出现心血管特征异常，红细胞和血管系统减少。观察到两种不同的心脏发育缺陷表型：（i）第一组胚胎的心脏发育停滞在心肌阶段，（ii）第二组胚胎的心脏发育停滞在心脏管阶段。两组胚胎还表现出红细胞和血管系统的减少。在受精后36小时（hpf），通过定量实时RT-PCR测定正常和缺陷胚胎中心脏发育（GATA 5和NKX2.5）、造血（GATA 1和GATA 2）和血管生成（VEGF）所必需的基因的mRNA水平。在两组缺陷胚胎中均观察到GATA 5、NKX2.5、GATA 1、GATA 2和VEGF mRNA水平显著降低。这些结果表明，斑马鱼胚胎中rtEa4或hEb转基因的过表达通过降低GATA 5、NKX2.5、GATA 1、GATA 2和VEGF mRNA水平，破坏心脏发育、造血和血管生成。
