GADD45B and colitis: To investigate the precise roles of hematopoietic and epithelial cells in experimental colitis, we generated chimeric mice using irradiated Gadd45β-WT and Gadd45β-KO recipient mice reconstituted with bone marrow cells from Gadd45β-WT or Gadd45β-KO donors and challenged these mice with DSS at 8 weeks posttransplantation (Fig. 2a).