Uberon definition : A thickened portion of ectoderm which serves as the precursor to the lens. SOX2 and
Pou2f1 are involved in its development[WP].;
Uberon related term : lens placodes;
Uberon Development note : Classical transplantation experiments using amphibian embryos suggested that the optic
vesicle is the source of lens-inducing signals sufficient to generate lens tissues
in competent ectoderm (reviewed in Grainger et al., 1996). More recent findings suggest
a multistep model for lens induction. There is now good evidence that lens specification
occurs at the neurula stage, before the optic vesicle contact the surface ectoderm,
and that neural crest cell migration in the frontonasal region is required to restrict
the position of the lens placode (Bailey et al., 2006);
Uberon Homology note : (...) an essentially similar sequence of events occurs during the embryonic development
of the vertebrate eye. The eye initially develops as a single median evagination of
the diencephalon that soon bifurcates to form the paired optic vesicles. As each optic
vesicle grows towards the body surface, its proximal part narrows as the optic stalk,
and its distal part invaginates to form a two-layered optic cup. (...) The optic cup
induces the overlying surface ectoderm first to thicken as a lens placode and then
to invaginate and form a lens vesicle that differentiates into the lens.[well established][VHOG];