Low temperature mitigates cardia bifida in zebrafish embryos.
The coordinated migration of bilateral cardiomyocytes and the formation of the cardiac cone are essential for heart tube formation. We investigated gene regulatory mechanisms involved in myocardial migration, and regulation of the timing of cardiac cone formation in zebrafish embryos. Through screening of zebrafish treated with ethylnitrosourea, we isolated a mutant with a hypomorphic allele of mil (s1pr2)/edg5, called s1pr2(as10) (as10). Mutant embryos with this allele expressed less mil/edg5 mRNA and exhibited cardia bifida prior to 28 hours post-fertilization. Although the bilateral hearts of the mutants gradually fused together, the resulting formation of two atria and one tightly-packed ventricle failed to support normal blood circulation. Interestingly, cardia bifida of s1pr2(as10) embryos could be rescued and normal circulation could be restored by incubating the embryos at low temperature (22.5°C). Rescue was also observed in gata5 and bon cardia bifida morphants raised at 22.5 °C. The use of DNA microarrays, digital gene expression analyses, loss-of-function, as well as mRNA and protein rescue experiments, revealed that low temperature mitigates cardia bifida by regulating the expression of genes encoding components of the extracellular matrix (fibronectin 1, tenascin-c, tenascin-w). Furthermore, the addition of N-acetyl cysteine (NAC), a reactive oxygen species (ROS) scavenger, significantly decreased the effect of low temperature on mitigating cardia bifida in s1pr2(as10) embryos. Our study reveals that temperature coordinates the development of the heart tube and somitogenesis, and that extracellular matrix genes (fibronectin 1, tenascin-c and tenascin-w) are involved.
Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
Che-Yi
CY
Lin
Cheng-Chen
CC
Huang
Wen-Der
WD
Wang
Chung-Der
CD
Hsiao
Ching-Feng
CF
Cheng
Yi-Ting
YT
Wu
Yu-Fen
YF
Lu
Sheng-Ping L
SP
Hwang
D000818:Animals; D002465:Cell Movement / Q000235:genetics; D002874:Chromosome Mapping; D003080:Cold Temperature; D004625:Embryo, Nonmammalian / Q000002:abnormalities* / Q000378:metabolism*; D005109:Extracellular Matrix / Q000235:genetics; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D063990:Gene Ontology; D006330:Heart Defects, Congenital / Q000196:embryology* / Q000517:prevention & control*; D009154:Mutation / Q000235:genetics; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
D005353:Fibronectins; D017382:Reactive Oxygen Species; D029961:Zebrafish Proteins