Abnormal enteric ganglia development in a Sox10 mouse mutant generated by gene targeting

Abstract

SOX10 mutations have been identified in human Waardenburg-Hirschsprung patients who displayed a varied degree of intestinal aganglionosis. The spontaneous Sox10 mutant Dom and the null mutant Sox10lacZ are characterized by the absence of enteric ganglia in the myenteric and submucosal plexuses in the distal hindgut. It has been suggested that the mutant enteric neural crest-derived progenitors failed to maintain their multipotency, resulted in a reduced progenitor cell pool and aganglionosis. We have generated a mouse mutant Sox10D5 , in which the transactivation domain and part of the Group E conserved region of Sox10 have been deleted. In the gut of 11.5 and 12.5dpc Sox10D5 mutants, a delayed colonization of enteric neural crest cells could be observed when we analysed the phenotype with a lacZ reporter mouse line. This abnormal phenotype was also observed by immunostaining using antibodies against p75NTR and PGP9.5 which are neural crest and neuronal markers. Interestingly, in the Sox10D5 mutants, the enteric neural crest cells could completely colonize the gut by 14.5 dpc, and no aganglionosis could be observed after this stage. However, the neuronal complexity in the mutant hindgut was reduced. At later stages, patchy and disorganized neuronal network of both cholinergic and NOS neurons could be seen. We have isolated the mutant enteric neural crest cells and cultured them at clonal density. Neurospheres could be formed from Sox10D5 mutant neural crest cells, and they showed a different proliferation rate when compared with wildtype. We are currently studying the differentiation potential of the mutant neural crest cells, in order to correlate the Sox10D5 mutation with the phenotype and to further investigate the functions of Sox10.