Induction of apoptosis and inhibition of cell growth by tbx5 knockdown contribute to dysmorphogenesis in Zebrafish embryos

Journal of Biomedical Science

Research

Jenher Lu¹  Renbing Tang¹  Anhang Yang¹  Hsinyu Lee²  Jennkan Lu³  Sielin Choo³  Shuyu Yeh³  Tzuchun Tsai⁴ 

[1] Department of Pediatrics and Pathology, Taipei Veterans General Hospital, Taipei, Taiwan;School of Medicine, National Yang Ming University, Taipei, Taiwan;Institute of Zoology, National Taiwan University, Taipei, Taiwan;Laboratory of Molecular Biology, Institute of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan;School of Medicine, National Yang Ming University, Taipei, Taiwan;Department of Medical Research and Education, National Yang-Ming University Hospital, Yilan, Taiwan;

关键词: zebrafish;    mitochondria;    apoptosis;    tbx5;    Holt-Oram syndrome;    cell cycle;   

DOI  :  10.1186/1423-0127-18-73

 received in 2011-05-22, accepted in 2011-10-08,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundThe tbx5 mutation in human causes Holt-Oram syndrome, an autosomal dominant condition characterized by a familial history of congenital heart defects and preaxial radial upper-limb defects. We report aberrant apoptosis and dormant cell growth over head, heart, trunk, fin, and tail of zebrafish embryos with tbx5 deficiency correspond to the dysmorphogenesis of tbx5 morphants.MethodsWild-type zebrafish embryos at the 1-cell stage were injected with 4.3 nl of 19.4 ng of tbx5 morpholino or mismatch-tbx5-MO respectively in tbx5 morphants and mismatched control group. Semi-quantitative RT-PCR was used to for expression analysis of apoptosis and cell cycle-related genes. TUNEL and immunohistochemical assay showed the apoptosis spots within the local tissues. Ultra-structure of cardiac myocardium was examined by transmission electron microscope.ResultsApoptosis-related genes (bad, bax, and bcl2), and cell cycle-related genes (cdk2, pcna, p27, and p57) showed remarkable increases in transcriptional level by RT-PCR. Using a TUNEL and immnuohistochemical assay, apoptosis was observed in the organs including the head, heart, pectoral fins, trunk, and tail of tbx5 knockdown embryos. Under transmission electron microscopic examination, mitochondria in cardiomyocytes became swollen and the myocardium was largely disorganized with a disarrayed appearance, compatible with reduced enhancement of myosin in the cardiac wall. The ATP level was reduced, and the ADP/ATP ratio as an apoptotic index significantly increased in the tbx5 deficient embryos.ConclusionOur study highlighted that tbx5 deficiency evoked apoptosis, distributed on multiple organs corresponding to dysmorphogenesis with the shortage of promising maturation, in tbx5 knockdown zebrafish embryos. We hypothesized that mesenchymal cell apoptosis associated with altered TBX5 level may subsequently interfered with organogenesis and contributed to dysmorphogenesis in tbx5 deficiency zebrafish embryos.

【 授权许可】

CC BY   
© Lu et al; licensee BioMed Central Ltd. 2011