PUBLICATION
Cardiac troponin T is essential in sarcomere assembly and cardiac contractility
- Authors
- Sehnert, A.J., Huq, A., Weinstein, B.M., Walker, C., Fishman, M., and Stainier, D.Y.
- ID
- ZDB-PUB-020514-12
- Date
- 2002
- Source
- Nature Genetics 31(1): 106-110 (Journal)
- Registered Authors
- Fishman, Mark C., Huq, Anja, Sehnert, Amy, Stainier, Didier, Walker, Charline, Weinstein, Brant M.
- Keywords
- none
- MeSH Terms
-
- Animals
- Base Sequence
- Cardiomyopathy, Hypertrophic, Familial/genetics
- Cloning, Molecular
- DNA/genetics
- Humans
- Mice
- Molecular Sequence Data
- Mutation
- Myocardial Contraction/genetics
- Myocardial Contraction/physiology*
- Myocardium/metabolism
- Myocardium/pathology
- Phenotype
- Sarcomeres/pathology
- Troponin T/deficiency
- Troponin T/genetics
- Troponin T/physiology*
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/physiology
- PubMed
- 11967535 Full text @ Nat. Genet.
Citation
Sehnert, A.J., Huq, A., Weinstein, B.M., Walker, C., Fishman, M., and Stainier, D.Y. (2002) Cardiac troponin T is essential in sarcomere assembly and cardiac contractility. Nature Genetics. 31(1):106-110.
Abstract
Mutations of the gene (TNNT2) encoding the thin-filament contractile protein cardiac troponin T are responsible for 15% of all cases of familial hypertrophic cardiomyopathy, the leading cause of sudden death in young athletes. Mutant proteins are thought to act through a dominant-negative mode that impairs function of heart muscle. TNNT2 mutations can also lead to dilated cardiomyopathy, a leading cause of heart failure. Despite the importance of cardiac troponin T in human disease, its loss-of-function phenotype has not been described. We show that the zebrafish silent heart (sih) mutation affects the gene tnnt2. We characterize two mutated alleles of sih that severely reduce tnnt2 expression: one affects mRNA splicing, and the other affects gene transcription. Tnnt2, together with alpha-tropomyosin (Tpma) and cardiac troponins C and I (Tnni3), forms a calcium-sensitive regulatory complex within sarcomeres. Unexpectedly, in addition to loss of Tnnt2 expression in sih mutant hearts, we observed a significant reduction in Tpma and Tnni3, and consequently, severe sarcomere defects. This interdependence of thin-filament protein expression led us to postulate that some mutations in tnnt2 may trigger misregulation of thin-filament protein expression, resulting in sarcomere loss and myocyte disarray, the life-threatening hallmarks of TNNT2 mutations in mice and humans.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping