Document Type

Article

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Our laboratory and others have shown that overexpression of Dlx5 stimulates osteoblast differentiation. Dlx5−/−/Dlx6−/− mice have more severe craniofacial and limb defects than Dlx5−/−, some of which are potentially due to defects in osteoblast maturation. We wished to investigate the degree to which other Dlx genes compensate for the lack of Dlx5, thus allowing normal development of the majority of skeletal elements in Dlx5−/− mice. Dlx gene expression in cells from different stages of the osteoblast lineage isolated by FACS sorting showed that Dlx2, Dlx5 and Dlx6 are expressed most strongly in less mature osteoblasts, whereas Dlx3 is very highly expressed in differentiated osteoblasts and osteocytes. In situ hybridization and Northern blot analysis demonstrated the presence of endogenous Dlx3 mRNA within osteoblasts and osteocytes. Dlx3 strongly upregulates osteoblastic markers with a potency comparable to Dlx5. Cloned chick or mouse Dlx6 showed stimulatory effects on osteoblast differentiation. Our results suggest that Dlx2 and Dlx6 have the potential to stimulate osteoblastic differentiation and may compensate for the absence of Dlx5 to produce relatively normal osteoblastic differentiation in Dlx5 knockout mice, while Dlx3 may play a distinct role in late stage osteoblast differentiation and osteocyte function.

Comments

Dev Biol. Author manuscript; available in PMC 2009 May 9. Published in final edited form as: Dev Biol. 2008 April 15; 316(2): 458–470. Published online 2008 January 16. doi: 10.1016/j.ydbio.2008.01.001 PMCID: PMC2679944 NIHMSID: NIHMS46571