Gene notes: One of the first genes to be expressed in nonneural ectoderm in amphioxus is BMP2/4 (Panopoulou et al. 1998). BMP2/4 homologues appear to have a very ancient role in distinguishing neural from nonneural ectoderm; in Drosophila as well as in amphioxus and vertebrates, BMP2/4 homologues are expressed in nonneural ectoderm and function in distinguishing neural from nonneural ectoderm (Francois & Bier, 1995 ; Sasai et al. 1995 ; Wilson & Hemmati-Brivanlou, 1995; Panopoulou et al. 1998). A change in level of BMP2/4 from very high in nonneural ectoderm to low in neural ectoderm appears to be a key factor in development of neural crest (Baker & Bronner-Fraser,1997a,1997b;Erickson&Reedy,1998;Marchantet al.1998 ;Selleck et al. 1998).

After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm.

todo - epidermis? todo - track down EHDAA2 class in new release

epidermal ectoderm, epithelial ectoderm

uberon

surface ectoderm, ventral ectoderm

In the early gastrula of vertebrates, factors from the organizer (e.g. noggin, chordin, and follistatin in Xenopus) antagonize the epidermalizing factor bone morphogenetic protein 4 (BMP4), thus dividing the epiblast into neuroectoderm. In Drosophila, decapentaplegic, the homologue of BMP4, interacts similarly with the protein short gastrulation, the homologue of chordin. Thus, a comparable molecular mechanism for distinguishing non-neural ectoderm from neural ectoderm was probably present in the common ancestor of all bilaterally symmetrical animals.[well established][VHOG]

UBERON:0005497

• adenohypophyseal placode