Analysis of gene expression levels in BBF2H7-/- chondrocytes. Mus musculus

BBF2H7 (BBF2 human homolog on chromosome 7), an ER-resident basic leucine zipper transcription factor, is activated in response to ER stress and abundantly expresses in chondrocytes. While BBF2H7 is widely expressed in many tissues and organs, the most intense signals were detected in the proliferating zone of the cartilage. We compared gene expressions in primary cultured chondrocytes prepared from rib cartilage between WT and BBF2H7-/- mice at E18.5. Primary cultured chondrocytes were prepared from E18.5 rib cartilage of WT and BBF2H7-/- mice. Chondrocytes were isolated using 0.2% collagenase D (Roche) after adherent connective tissue was removed by 0.2% trypsin (Sigma) and collagenase pretreatment. Isolated chondrocytes were maintained in α-MEM (Gibco) supplemented with 10% FCS and 50 µg/mL ascorbic acid. Adenovirus vectors expressing the mouse p60 BBF2H7 (1-377 aa, BBF-N) were constructed with the AdenoX Expression system (Clontech), according to the manufacturer’s protocol. The cells were infected with adenoviruses 30 h before analysis. Overall design: We compared gene expressions in primary cultured chondrocytes prepared from rib cartilage between WT and BBF2H7-/- mice at E18.5 using a microarray and various genes associated with protein secretory pathway and ER biogenesis were significantly down-regulated in BBF2H7-/- chondrocytes. We infected primary cultured chondrocytes prepared from BBF2H7-/- mice with adenovirus expressing p60 BBF2H7. Several genes were up-regulated and we picked up them as the direct target of BBF2H7.