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]. [ MP : 0001676 http://en.wikipedia.org/wiki/Apical_ectodermal_ridge ]

This is just here as a test because I lose it

Term information

database cross reference
Subsets

pheno_slim

axiom lost from external ontology
  • relationship loss: subclass proliferative region (TAO:0000098)[TAO]
curator note
  • note that media, dorsal fins etc have AERs.
definition
  • 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].
depicted by
  • http://upload.wikimedia.org/wikipedia/commons/5/56/Limbbuddiagram.jpg
external definition
  • 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]
function notes
  • 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
has exact synonym
  • apical epidermal ridge
has related synonym
  • AER
  • crista ectodermalis apicalis
id
  • UBERON:0004356
taxon notes
  • The AER of tetrapods regresses after specification of skeletal progenitors, the AER of teleosts form an elongating fin fold