WDR5 also known as BIG3 is a member of the WD repeat protein family. WDR5 is a crucial component of the Trithorax (TRX) histone methyltransferase complexes, which are vital for regulating gene expression during vertebrate development. WDR5 is primarily located in the nucleus, where WDR5 plays a significant role in the activation of Hox genes and the global trimethylation of histone H3 at lysine 4 (H3K4me3), a modification associated with active transcription. The presence of WDR5 in osteoblasts, chondrocytes, osteocytes, and marrow stromal cells highlights WDR5′s importance in bone development and differentiation, particularly in accelerating osteoblast differentiation through seven WD-repeats, which facilitate protein-protein interactions essential for function.