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 alpha 1(II) mRNA in variou s cartilaginous tissues were examined using newly isolated cDNA clones encoding rabbit type II procollagen amino- and carboxy-terminal prope ptide regions. In nonchondrogenic nucleus pulposus, the switching of t he mRNA from the long form to the short form was accompanied by disc m aturation after birth. Interestingly, the short transcript was also ex pressed preferentially in human chordoma tissues as aberrant chordal v estiges. These results suggest an abundance of the differentiated chon drocyte-like phenotype in the heterogeneous notochordal remnants.