Conditional Gene Targeting Reveals A Critical Role Of Novel Zinc Finger Protein ZBTB20 In Chondrogenesis

ZBTB20 is a newly identified zinc finger protein gene, which is expressed in a variety of tissues; however, its function is not well-understood yet. We generated ZBTB20 global knockout mice, and found the knockout mice were runted, indicating that ZBTB20 may play an important role in the regulation of body growth and development. To better characterize its expression pattern in vivo and facilitate functional studies, we generated monoclonal antibodies against ZBTB20, and obtained 9A10 clone which exhibits good performance in ELISA, immunohistochemistry, Western-blotting and immunoprecipitation, with high sensitivity and specificity. Compared to the polyclonal antibodies against ZBTB20 that we generated previously, monoclonal antibody 9A10 is more sensitive, and more specific. By immunohistochemical analysis with 9A10, we found that ZBTB20 is specifically and highly expressed in chondrocytes. Further experiments indicate that ZBTB20 starts to be activated in chondrocytes at E14.5 during the embryonic period, and is preferentially expressed in the hypertrophic zone of the growth plate only. Then we used Cre/LoxP system to generate a mouse model with the ZBTB20 gene selectively ablated within chondrocytes. The knock-out mice show increased proliferartion of chondrocytes, expanded hypertrophic zone, and disrupted structure of growth plate of long bones. These data indicate that ZBTB20 may have a critical role in chondrogenesis.