WDR5, also designated BMP-2-induced gene 3 kb or BIG-3, belongs to the family of WD-40 repeat proteins, and is essential for vertebrate development, Hox gene activation and global H3K4 trimethylation. This protein is expressed in osteoblasts, chondrocytes, osteocytes and marrow stromal cells. WDR5 may play a role in its function of accelerating osteoblast differentiation. Recombinant human WDR5 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.