The phenotypic characterization of mouse floxed Fam20b chondrocytes, a novel articular cartilage-derived cell line with differentiation potential

FAM20B is a newly identified kinase involved in proteoglycan biosynthesis. Inactivation of <i>Fam20b</i> in joint cartilage leads to chondrosarcoma. Generation of chondrocytes cell line carrying floxed <i>Fam20b</i> allele can offer a valuable tool for the study of the role of <i>Fam20b</i> as well as the molecular events in chondrocyte biology and cartilage diseases. The limitations in the primary culture of chondrocytes necessitate the development of chondrocyte cell line. In this study, we established and characterized the immortalized mouse floxed <i>Fam20b</i> chondrocyte cell line. The primary mouse floxed <i>Fam20b</i> chondrocytes were isolated from the articular cartilage of knee joints and immortalized using lentivirus containing Simian Virus 40 T-antigen (SV40 T-Ag). The immortalized cell line was verified by genomic integration of SV40 T-Ag and proliferated at a high rate relative to their primary counterparts. The immortalized chondrocyte cell line not only retained the typical ultrastructural morphology and important phenotypic characteristics of articular cartilage, but also possessed strong differentiation potential upon three-dimensional pellet culture. Thus, we, for the first time, describe the development of immortalized mouse floxed <i>Fam20b</i> chondrocytes and present an alternative for the limited number of articular chondrocyte cell lines for the study of cartilage biology.