CCN family genes in the development and differentiation of cartilage tissues

CCN family is a novel family of proteins consisting of several modulator molecules. The members display a variety of physiological and pathological functions ; hence they are currently attracting the interest of a number of biologists. In terms of the development and regeneration of cartilage tissues, CCN2/connective tissue growth factor (CTGF) is best known among the CCN family members, since it efficiently promotes endochondral ossification and articular cartilage regeneration. Recently, it has been uncovered how CCN2 gene expression is duly regulated along with the differentiation of chondrocytes, which is uncovering the genetic program leading to cartilage tissue development. Moerover, production of other members, such as CCN1 and CCN4, are occasionally observed in chondrocytes, suggesting the contribution of the entire CCN family members to the developmental process of cartilage in vivo.