A 1,064 BP FRAGMENT FROM THE PROMOTER REGION OF THE COL11A2 GENE DRIVES LACZ EXPRESSION NOT ONLY IN CARTILAGE BUT ALSO IN OSTEOBLASTS ADJACENT TO REGIONS UNDERGOING BOTH ENDOCHONDRAL AND INTRAMEMBRANOUS OSSIFICATION IN MOUSE EMBRYOS

We isolated a 1,064 bp promoter fragment that extended from the 3'-end of the adjacent gene for retinoic X receptor-beta to beyond the most clearly defined start site of the mouse Col11a2 gene. The fragment was then joined to a beta-galactosidase gene and used to prepare transgen ic mice. Three independent lines of transgenic mice were generated. Th e reporter beta-galactosidase gene was expressed in essentially all ca rtilaginous tissues in 15.5-day-old mouse embryos. In addition, the co nstruct was expressed in osteoprogenitors within developing periosteum and in osteoblasts within mineralized bone. This pattern of expressio n was evident during both endochondral and intramembranous bone format ion. Therefore, the results suggest that 1,064 bp promoter fragment ca n drive tissue-specific expression of the Col11a2 gene.