SoxE proteins are Differentially Required in Mouse Adrenal Gland Development

Sry-box (Sox)8, Sox9, and Sox10 are all strongly expressed in the neural crest. Here, we studied the influence of theseclosely related transcription factors on the developing adrenal medulla as one prominent neural crest derivative. WhereasSox9 was not expressed, both Sox8 and Sox10 occurred widely in neural crest cells migrating to the adrenal gland and inthe gland itself, and they were down-regulated in cells expressing catecholaminergic traits. Sox10-deficient mice lackedan adrenal medulla. The adrenal anlage was never colonized by neural crest cells, which failed to specify properly at thedorsal aorta and died apoptotically during migration. Furthermore, mutant neural crest cells did not express Sox8. Strongadrenal phenotypes were also observed when the Sox10 dimerization domain was inactivated or when a transactivationdomain in the central portion was deleted. Sox8 in contrast had only minimal influence on adrenal gland development.Phenotypic consequences became only visible in Sox8-deficient mice upon additional deletion of one