The present invention provides a novel polypeptide, Connective Tissue GrowthFactor (CTGF), polynucleotides CTGF, and including 5'and 3' untranslatednucleotides, antibodies reactive with CTGF and means for producing CTGF. Alsoprovided are diagnostic and therapeutic methods for using CTGF, as well as anassay for identifying compositions which affect the expression of CTGFpolynucleotide. The invention provides a novel TGF-.beta. responsive elementupstream of the polynucleotide encoding CTGF structural gene.