Analysis of postembryonic heart development and maturation in the zebrafish, Danio rerio.
BACKGROUND
Cardiac maturation is vital for animal survival and must occur throughout the animal's life. Zebrafish are increasingly used to model cardiac disease; however, little is known about how the cardiovascular system matures. We conducted a systematic analysis of cardiac maturation from larvae through to adulthood and assessed cardiac features influenced by genetic and environmental factors.


RESULTS
We identified a novel step in cardiac maturation, termed cardiac rotation, where the larval heart rotates into its final orientation within the thoracic cavity with the atrium placed behind the ventricle. This rotation is followed by linear ventricle growth and an increase in the angle between bulbous arteriosus and the ventricle. The ventricle transitions from a rectangle, to a triangle and ultimately a sphere that is significantly enveloped by the atrium. In addition, trabeculae are similarly patterned in the zebrafish and humans, both with muscular fingerlike projections and muscle bands that span the cardiac chamber. Of interest, partial loss of atrial contraction in myosin heavy chain 6 (myh6/wea(hu423/+)) mutants result in the adult maintaining a larval cardiac form.


CONCLUSIONS
These findings serve as a foundation for the study of defects in cardiovascular development from both genetic and environmental factors.
Department of Biology, Queens College, City University of New York, Flushing New York and The Graduate Center, City University of New York, New York, New York, USA.
Corinna
C
Singleman
Nathalia G
NG
Holtzman
D000818:Animals; D006325:Heart Atria / Q000196:embryology; D006330:Heart Defects, Congenital / Q000196:embryology / Q000209:etiology / Q000235:genetics; D006352:Heart Ventricles / Q000166:cytology / Q000196:embryology*; D009154:Mutation; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
D029961:Zebrafish Proteins; C481025:myh6 protein, zebrafish; D018995:Myosin Heavy Chains