| Type | MGI:General | Description | in mutant skeletons, the proliferative and hypertrophic zones appeared less distinct, and the columns of chondrocytes in the growth plate were disorganized with little bone replacement similar to limb cartilage, chondrocytes of the vertebral bodies were also disorganized; the nucleus porposus was reduced and the annulus fibrosus appeared less distinct the number of hypertrophic chondrocytes forming vertebral bodies was decreased relative to wild-type, although the size of the vertebrae was similar to wild-type in situ hybridization revealed reduced Indian hedgehog expression in prehypertrophic chondrocytes, reflecting a decrease in the number of prehypertrophic chondrocytes in mutant cartilage; in addition, TUNEL analysis indicated that apoptosis of hypertrophic chondrocytes, a critical step for endochondral ossification, was inhibited in mutant cartilage |
