Clock Genes Influence Gene Expression in Growth Plate and Endochondral Ossification in Mice

Chondrogenesis is influenced by clock genes, particularly through the modulation of Indian hedgehog (Ihh) expression in chondrocytes.

• Clock genes are expressed with rhythmic patterns in cultured chondrocytes and the rib growth plate of mice.
• Chondrogenesis is inhibited in cells with stable expression of Period-1 (Per1) and in mice lacking BMAL1.
• Ihh promoter activity is regulated by various clock gene products, showing clear circadian patterns.
• BMAL1 deficiency results in reduced Ihh expression and smaller body size in mice compared to wild-type.
• Loss of BMAL1 disrupts rhythmic expression of both Per1 and Ihh in the growth plate.
• Dexamethasone exposure leads to rhythmic Ihh expression in ATDC5 cells.

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