Id proteins are negative regulators of basic helix-loop-helix gene products and participate in many developmental processes. We have evaluated the expression of Id2 in the developing chick heart and found expression in the cardiac neural crest, secondary heart field, outflow tract, inflow tract, and anterior parasympathetic plexus. Cardiac neural crest ablation in the chick embryo, which causes structural defects of the cardiac outflow tract, results in a significant loss of Id2 expression in the outflow tract. Id2 is also expressed in Xenopus neural folds, branchial arches, cardiac outflow tract, inflow tract, and splanchnic mesoderm. Ablation of the premigratory neural crest in Xenopus embryos results in abnormal formation of the heart and a loss of Id2 expression in the heart and splanchnic mesoderm. This data suggests that the presence of neural crest is required for normal Id2 expression in both chick and Xenopus heart development and provides evidence that neural crest is involved in heart development in Xenopus embryos.
Bibliographical noteFunding Information:
This work was supported by an American Heart Association Fellowship (#0020507Z) to BJM, an American Heart Association Scientist Development Award (#9930216N) to JLL, and gifts from the Andrew David Sit Foundation and Sit Investment Associates Foundation to JLL. Special thanks to Marianne Bronner-Fraser for her continued support.
- Cardiac neural crest
- Cardiac outflow tract
- Heart development
- Helix-loop-helix protein
- Neural crest
- Secondary heart field