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Regulation of cell movements during heart tube assembly in zebrafish
Author(s) -
Yelon Deborah,
GaravitoAguilar Zayra V.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.181.1
Subject(s) - zebrafish , microbiology and biotechnology , biology , morphogenesis , mutant , fibronectin , transcription factor , gene , genetics , extracellular matrix
Heart tube assembly requires the fusion of bilateral cardiomyocyte populations as they move toward the embryonic midline. The bHLH transcription factor Hand2 is essential for cardiac fusion; however, the effector genes that execute this function of Hand2 are unknown. Here, we provide the first evidence for a downstream component of the Hand2 pathway that mediates cardiac morphogenesis. Although hand2 is expressed in cardiomyocytes, mosaic analysis demonstrates that hand2 plays a non‐autonomous role in regulating cardiomyocyte movement. Gene expression profiles reveal heightened expression of fibronectin 1 ( fn1 ) in hand2 mutant embryos. Reciprocally, overexpression of hand2 leads to decreased Fibronectin levels. Furthermore, reduction of fn1 function enables rescue of cardiac fusion in hand2 mutants: bilateral cardiomyocyte populations merge and exhibit improved tissue architecture, albeit without major changes in apicobasal polarity. Together, our data provide a novel example of a tissue creating a favorable environment for its morphogenesis: the Hand2 pathway establishes an appropriate environment for cardiac fusion through negative modulation of Fn1 levels. Research in the Yelon lab is supported by the National Institutes of Health, American Heart Association, and March of Dimes.