CLONING OF EQUINE TYPE-II PROCOLLAGEN AND THE MODULATION OF ITS EXPRESSION IN CULTURED EQUINE ARTICULAR CHONDROCYTES

The complete nucleotide sequence of equine type II procollagen has not been previously reported, and equine-specific probes have not been av ailable. We report the complete sequence and discuss the molecular cha racteristics of equine type II procollagen mRNA which was cloned from a cDNA library prepared from mRNA isolated from equine articular chond rocytes. The coding sequence (4257 bp) was 92.4% homologous to the cDN A of the human sequence, and the propeptide was 97% identical to the h uman sequence. We demonstrated that when equine chondrocytes are grown in phenotypically-maintained cultures, the expression of type II proc ollagen is linked to the age of the animal. Additionally, in cultures of young equine chondrocytes, IL1-beta and TNF-alpha both reduced the expression of type II procollagen mRNA in a dose responsive manner.