The LIM protein fhlA is essential for heart chamber development in zebrafish embryos

Xie, H., Fan, X., Tang, X., Wan, Y., Chen, F., Wang, X., Wang, Y., Li, Y., Tang, M., Liu, D., Jiang, Z., Liu, X., Yuan, W., Li, G., Ye, X., Zhou, J., Deng, Y., and Wu, X.
Current Molecular Medicine   13(6): 979-92 (Journal)
Registered Authors
Deng, Yun, Wu, Xiushan
MeSH Terms
  • Animals
  • Cell Count
  • Embryo, Nonmammalian/metabolism
  • Embryonic Development/drug effects
  • Embryonic Development/genetics
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental/drug effects
  • Heart/drug effects
  • Heart/embryology*
  • Heart/physiology
  • Humans
  • LIM Domain Proteins/genetics
  • LIM Domain Proteins/metabolism*
  • Morpholinos/pharmacology
  • Organ Size/drug effects
  • Organ Size/genetics
  • Organ Specificity/drug effects
  • Organ Specificity/genetics
  • Phenotype
  • RNA, Messenger/genetics
  • RNA, Messenger/metabolism
  • Signal Transduction/drug effects
  • Signal Transduction/genetics
  • Tretinoin/metabolism
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
23438903 Full text @ Curr. Mol. Med.

Four-and-a-half LIM proteins FHL1-3 play important roles in cardiovascular pathophysiology. However, their roles in heart development remain unclear. Here, we report that fhlA, the zebrafish homolog of human FHL1, was found to be expressed around the 22-somite stage. After 24 hpf, expression was restricted to the heart. fhlA knockdown caused an enlarged cardiac chamber phenotype with up-regulated expression of the cardiac markers, but fhlA overexpression reduced the sizes of the cardiac chambers and down-regulated expression of the markers. The morphology associated with the cmlc2, amhc, and vmhc expression patterns at the 22 somite and 24 hpf stages included a broadened domain in embryos lacking fhlA and a smaller domain in embryos overexpressing fhlA. The changes in the sizes of the chambers were attributed to the changes in the number of ventricular and atrial cells. Loss of fhlA caused a longer heart period and pause between heartbeats in M-modes than in controls, but fhlA overexpression caused shorter systolic and diastolic intervals. Abnormal cardiac chambers and physiological function were found to be largely rescued. We also showed the expression of fhlA in the heart to be increased by retinoic acid (RA) and decreased by the RA synthase inhibitor DEAB. Both fhlA and RA signaling caused a phenotype characterized by the morphological alterations in the chamber sizes, suggesting that the role of fhlA in heart development is probably regulated by RA signaling. Taken together, these results showed that fhlA regulates the size of the heart chamber by reducing the number of cardiac cells.

Genes / Markers
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes