Heterogeneity of proteoglycans in developing chick limb cartilage.

Proteoglycan heterogeneity was studied during the maturation of embryonic-chick limb cartilage in vivo. The results suggest that during the differentiation of limb-bud cartilage the aggregated forms of proteoglycans increase between stages 24 and 35, whereas the non-aggregated or monomeric forms decrease. Only one link protein is found in stage-24 limb buds, whereas two are present at stage 35. Evidence suggests that the synthesis of link proteins may be a regulatory factor in limb chondrogenesis.