Role of Primary Cilia in Skeletal Disorders

Table 1

The role of primary cilia in bone development illustrated by the conditional knock out mouse model.

Gene	Function
IFT20	Col1-CreERT;IFT20^fl/fl and Osx-Cre;IFT20^fl/fl mice exhibit reduced bone mass and strength. Deletion of IFT20 impairs osteoblast polarity and cell alignment via ceramide-PKCζ-β-catenin signaling [96]
IFT140	Osx-Cre;IFT140^fl/fl mice exhibited dwarf phenotypes, such as short bone length, less bone mass, and decreased bone mineral apposition rate [21]
IFT80	Osx-Cre;IFT80^fl/fl mice show reduced bone mass with impaired osteoblast differentiation; IFT80 is required for osteoblast differentiation by balancing between canonical and noncanonical Hedgehog pathways [11]
KIF3a	Osx-Cre;Kif3a^fl/fl mice display an osteopenia phenotype with impaired osteoblast function. Kif3a deletion in osteoblast impairs osteoblast-mediated bone formation through multiple pathways including intracellular calcium, hedgehog, and Wnt signaling [16]; Col1-Cre;Kif3a^fl/fl mice have normal bone development but reduced bone formation in response to a cyclic ulnar loading [97]
PKD	Osx-Cre;Pkd1^flox/m1Bei mice show reduced bone mass, mineral apposition rates, increased adipogenesis in bone marrow, and impaired osteoblast differentiation [19]