The function and regulation of chick Ebf genes in somite development

The three chick Ebf (Early B-cell Factor) genes are members of EBF helix loop helix transcription factors. EBFs have been characterised for their roles in differentiation of B-lymphocytes and neural cells.Recently,a new role for some EBFs in bone development has been investigated. However,their expression profile and regulation in the somites (axial skeleton precursor) have yet to be elucidated. I have found cEbf somitic expression in medial (cEbf1) and lateral (cEbf2 and cEbf3) sclerotomal domains and later around vertebral cartilage anlagen of body,pedicles (cEbf1) and arch (cEbf2 and cEbf3).I have presented a model in which expression cEbf1 is initiated by low dose of BMP4 from lateral mesoderm and maintained by Shh from notochord.However, the other two chick Ebf genes are induced by BMP4 and inhibited by high dose of Shh.I have also found that cEbf1 can induce other sclerotomal markers,Pax1 and Sox9,and dermomyotomal marker,MyoD,but antagonises lateral markers,cEbf3 and Pax3.Thus,cEbf1 is a sclerotomal marker expressed in axial skeletogenic tissues under control of Shh and Bmp4 and that this expression is crucial for sclerotome development and mediolateral patterning of somites.