PUBLICATION
Zebrafish tinman homolog demarcates the heart field and initiates myocardial differentiation
- Authors
- Chen, J.N. and Fishman, M.C.
- ID
- ZDB-PUB-970207-6
- Date
- 1996
- Source
- Development (Cambridge, England) 122(12): 3809-3816 (Journal)
- Registered Authors
- Chen, Jau-Nian, Fishman, Mark C.
- Keywords
- Nkx2.5; heart; zebrafish; myocardial differentiation; tinman
- MeSH Terms
-
- Stem Cells
- Drosophila Proteins*
- Immunohistochemistry
- Cell Transplantation
- Cardiomegaly/genetics
- Trans-Activators*
- Antigens, Differentiation
- Xenopus Proteins*
- Cell Differentiation
- Homeodomain Proteins/biosynthesis
- Homeodomain Proteins/genetics*
- Homeodomain Proteins/isolation & purification*
- Gene Expression Regulation, Developmental
- Recombinant Proteins/biosynthesis
- Cloning, Molecular
- Gene Dosage
- Sequence Homology, Amino Acid
- Molecular Sequence Data
- Zebrafish/embryology
- Zebrafish/genetics*
- Animals
- Transfection
- Sequence Analysis, DNA
- Repressor Proteins*
- Heart/embryology*
- Amino Acid Sequence
- Transcription Factors*
- Base Sequence
- In Situ Hybridization
- PubMed
- 9012502 Full text @ Development
Citation
Chen, J.N. and Fishman, M.C. (1996) Zebrafish tinman homolog demarcates the heart field and initiates myocardial differentiation. Development (Cambridge, England). 122(12):3809-3816.
Abstract
The fashioning of a vertebrate organ requires integration of decisions of cell fate by individual cells with those that regulate organotypic form. Logical candidates for this role, in an organ such as the heart, are genes that initiate the differentiation process leading to heart muscle and those that define the earliest embryonic heart field, but for neither class are genes defined. We cloned zebrafish Nkx2.5, a homolog of the tinman homeodomain gene needed for visceral and cardiac mesoderm formation in Drosophila. In the zebrafish, its expression is associated with cardiac precursor cells throughout development, even in the early gastrula, where the level of zebrafish Nkx2.5 is in a gradient which spatially matches the regional propensity of ventral-marginal cells to become heart. Overexpression of Nkx2.5 causes formation of disproportionally larger hearts in otherwise apparently normal embryos. Transplanted cell expressing high levels of Nkx2.5 express cardiac genes even in ectopic locales. Fibroblasts transfected with myc-tagged Nkx2.5 express cardiac genes. These effects require the homeodomain. Thus, Nkx2.5 appears to mark the earliest embryonic heart field and to be capable of initiating the cardiogenic differentiation program. Because ectopic cells or transfected fibroblasts do not beat, Nkx2.5 is likely to be but one step in the determination of cardiac myocyte cell fate. Its overexpression increases heart size, perhaps by bringing cells on the edge of the field to a threshold level for initiation of cardiac differentiation.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping