system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Animals, Cell Differentiation, Choline Kinase, Chondrocytes, Embryo, Mammalian, Embryonic Development, Forelimb, Growth Plate, Humans, Mice, Mice, Knockout, Osteogenesis, Phosphatidylcholines.
user
Is choline kinase beta required for normal endochondral bone formation? Context: Choline kinase has three isoforms encoded by the genes Chka and Chkb. Inactivation of Chka in mice results in embryonic lethality, whereas Chkb(-/-) mice display neonatal forelimb bone deformations. To understand the mechanisms underlying the bone deformations, we compared the biology and biochemistry of bone formation from embryonic to young adult wild-type (WT) and Chkb(-/-) mice. The deformations are specific to the radius and ulna during the late embryonic stage. The radius and ulna of Chkb(-/-) mice display expanded hypertrophic zones, unorganized proliferative columns in their growth plates, and delayed formation of primary ossification centers. The differentiation of chondrocytes of Chkb(-/-) mice was impaired, as was chondrocyte proliferation and expression of matrix metalloproteinases 9 and 13. In chondrocytes from Chkb(-/-) mice, phosphatidylcholine was slightly lower than in WT mice whereas the amount of phosphocholine was decreased by approximately 75%. In addition, the radius and ulna from Chkb(-/-) mice contained fewer osteoclasts along the cartilage/bone interface.
assistant
Chkb has a critical role in the normal embryogenic formation of the radius and ulna in mice. Final Decision: yes