| Abstract [eng] |
Danio rerio (Hamilton, 1822) is a powerful vertebrate model system, which provides a unique combination of advantages that are important for an investigation of cardiovascular development and regeneration. However, conditional mutagenesis, which is essential for dissecting a role of developmental genes in regeneration, has not been demonstrated in the adult zebrafish. This remains a main disadvantage of D. rerio model system. The main aim of this research project was to use insertional gene trap alleles, tbx5atpl58 and fli1btpl50, to study cardiovascular development and regeneration in D. rerio. During this studies, the first conditional induction of the mutation was performed in the adult fish. Incubation of tbx5atpl58R;tnnt2a:CreERT2 adults in 4-hydroxytamoxifen induced a recombination between lox71 and lox66 sites, inverted the gene trap mutagenic cassette, and resulted in a successful re-mutation of tbx5atpl58R locus specifically in the heart. Generated conditional mutants with hearts mosaic for tbx5atpl58R/tpl58R, tbx5atpl58R/tpl58, and tbx5atpl58/tpl58 cardiomyocytes exhibited severe cardiac regeneration phenotypes. This indicated that tbx5a plays a critical role in zebrafish heart regeneration. Six new insertional genetrap mutant lines were characterized using iPCR and 5’RACE methods. One of the identified gene trap lines (fli1btpl50) that had a mutation in fli1b gene was found to undergo normal regeneration of the blood vessels, but exhibited GFP overexpression in vasculature and blood at 7 days after partial amputation of the caudal fin. This suggested that fli1b might be important for regeneration of vascular system, but it’s role is most likely being compensated by it’s paralog fli1a. |
