Expression of cartilage-matrix genes and localization of their translation products in the embryonic chick eye.

The presence of cartilage-matrix molecules in the embryonic chick eye was shown by means of measuring RNA expression and immunostaining studies. The molecules examined were proteoglycan core protein (PG-core), link protein (LP), cartilage-matrix protein (CMP) and type II collagen. The genes encoding these proteins are expressed in 8- to 11-day embryonic chick eyes at constant steady-state levels. Immunopositive stained tissues include sclera, choroid, cornea, lens capsule (PG-core, LP, CMP), lens epithelium, lens fibers (LP, CMP) and the membranes in the retina (LP). In addition, data from comparative studies employing the eyes from the proteoglycan core-protein-deficient mutant, nanomelia, indicate that levels of mRNA for core protein are almost absent and that CMP is reduced in the above-mentioned tissues.