Disrupted expression of matrix genes in the growth plate of the mouse cartilage matrix deficiency (cmd) mutant

Chondrodysplasia in the autosomal recessive cartilage matrix deficiency (cmd) mutant is caused by lack of the proteoglycan aggrecan arising from a mutation in the gene. Homozygous cmd/cmd mice are characterized by disorganisation of chondrocytes in the growth plate, disproportionate dwarfism, cleft palate, and perinatal lethality. We have studied the impact of the aggrecan deficiency on the expression of other matrix genes during the differentiation of chondrocytes in the growth plate of cmd/cmd 18.5 day fetuses. Compared with the wild‐type, there are significant differences in the growth plates of cmdmutants in the combinations of co‐expression of genes encoding the glycoprotein link protein, proteoglycan syndecan 3, collagens α1( X ) [Col10a1], α2(XI) [Col11a2], and the alternative transcripts of α1(II) [Col2a1type IIA form], and α1(IX) [Col9a1long and short forms]. The discordance of gene expression in cmdchondrocytes may be additional factors contributing to the disrupted cellular architecture of the growth plate resulting from the primary absence of aggrecan. Dev. Genet. 22:349–358, 1998. © 1998 Wiley‐Liss, Inc.