Preferential expression of alternatively spliced transcript of type II procollagen in the rabbit notochordal remnant and developing fibrocartilages

Expression patterns for the two isoforms of α1(II) mRNA in various cartilaginous tissues were examined using newly isolated cDNA clones encoding rabbit type II procollagen amino- and carboxy-terminal propeptide regions. In nonchondrogenic nucleus pulposus, the switching of the mRNA from the long form to the short form was accompanied by disc maturation after birth. Interestingly, the short transcript was also expressed preferentially in human chordoma tissues as aberrant chordal vestiges. These results suggest an abundance of the differentiated chondrocyte-like phenotype in the heterogeneous notochordal remnants.