Multilayered ectodermal region at the distal tip of a limb or fin bud necessary for the proper development of the underlying mesenchyme[MP,modified]. Along with the zone of polarizing activity, it is a crucial organizing region during limb development[WP]. [ http://en.wikipedia.org/wiki/Apical_ectodermal_ridge MP:0001676 ]
Synonyms: apical epidermal ridge
Term information
- XAO:0004121
- Wikipedia:Apical_ectodermal_ridge
- UMLS:C1516037 (ncithesaurus:Apical_Ectodermal_Ridge)
- EMAPA:32744
- AAO:0010760
- ZFA:0001702
- TAO:0002146
- NCIT:C34109
pheno_slim
relationship loss: subclass proliferative region (TAO:0000098)[TAO]
Distal ectodermal thickening which forms along the anterior-posterior limb axis. Signaling from this region influences proximal-distal patterning of the limb. Structure is missing in some lineages (salamanders, Eleutherodactylus coqui) however morphologically their indistinct distal ectoderm may still be involved in signaling.[AAO]
Proliferative region that is part of the developing fin fold or fin.[TAO]
maintaining mesenchyme in plastic proliferating state; maintaining expression of A-P axis genes; interacting with D-V proteins. Genes: AER induced by Fgf10 in mesenchyme. AER secretes Fgf8, which stimulates mitosis in the mesenchyme causing Fgf10 production - positive feedback loop
The AER of tetrapods regresses after specification of skeletal progenitors, the AER of teleosts form an elongating fin fold