Cartilage Acidic Protein 1 (CRTAC1)

CRTAC1 may be an extracellular matrix protein expressed in bone, cartilage, and cultured chondrocytes.The deduced 653-amino acid CRTAC1 protein has a signal peptide and a C-terminal EGF-like domain. SDS-PAGE analysis showed expression of a 70-kD protein, close to the predicted size of 68 kD. RT-PCR analysis confirmed the cultured chondrocyte-specific expression of CRTAC1 and also detected expression in bone and cartilage primary tissue. CRTAC1 expression was inducible in mesenchymal stem cells cultured in chondrogenic medium. Northern blot analysis revealed expression of a 3.0-kb transcript in cultured chondrocytes as well as in lung; no expression was detected in heart, placenta, liver, skeletal muscle, pancreas, and blood. A 2.4-kb CRTAC1 transcript was detected in brain.