Hensen’s Node: The Embryonic Organizer of the Chick
The chick embryo is a well-established model system for studying vertebrate embryogenesis. Its relatively large size during gastrulation and neurulation provides numerous and unique experimental possibilities. Today, techniques are available for culturing, manipulating, and mapping of avian embryos, tissues or single cells (Schoenwolf 2001). A wealth of information has been accumulated on pattern formation, cell lineages, cell specifications, organogenesis, tissue interactions, and inductive or responsive potentials. Avian versions of most developmental control genes are by now cloned and characterized. Their transcriptional responses to ectopically applied soluble factors or antagonists are often known. However, only a few of them have been functionally investigated after reintroduction into the living embryo via infection with viruses or the electroporation of cloned expression vectors. To date, lossof-function experiments have only rarely and with limited success been performed, using anti-sense or dominant negative strategies. Thus, with respect to genetic or pseudo-genetic approaches, the avian embryo as an experimental system still suffers from drawbacks. However, the availability of novel molecular tools such as morpholino oligonucleotides or small interfering RNAs indicates the ongoing search for novel experimental strategies.
KeywordsChick Embryo Neural Plate Primitive Streak Avian Embryo Area Pellucida
Unable to display preview. Download preview PDF.
- Eyal-Giladi H, Kochav S (1976) From cleavage to primitive streak formation: a complementary normal table and a new look at the first stages of the development of the chick. I. General morphology. Dev Biol 49: 321–337Google Scholar
- Ryan AK, Blumberg B, Rodriguezesteban C, Yoneitamura S, Tamura K, Tsukui T, Delapena J, Sabbagh W, Greenwald J, Choe S, Norris DP, Robertson EJ, Evans RM, Rosenfeld MG, Bel-monte JCI (1998) Pitx2 determines left-right asymmetry of internal organs in vertebrates. Nature 394: 545–551PubMedCrossRefGoogle Scholar
- Spemann H, Mangold H (1924) Über die Induktion von Embryoanlagen durch Implantation artfremder Organisatoren. Roux Arch Entwicklungsmech 100: 599–638Google Scholar
- Tsukui T, Capdevila J, Tamura K, Ruiz-Lozano P, Rodriguez-Esteban C, Yonei-Tamura S, Ma-gallon J, Chandraratna RAS, Chien K, Blumberg B, Evans RM, Belmonte JCI (1999) Multiple left-right asymmetry defects in Shh(-/-) mutant mice unveil a convergence of the Shh and retinoic acid pathways in the control of Lefty-1. Proc Nail Acad Sci USA 96: 11376–11381CrossRefGoogle Scholar