A two-amino-acid substitution in the transcription factor RORγt disrupts its function in TH17 differentiation but not in thymocyte development

Abstract

The transcription factor RORγt regulates differentiation of the T_H17 subset of helper T cells, thymic T cell development and lymph-node genesis. Although elimination of RORγt prevents T_H17 cell-mediated experimental autoimmune encephalomyelitis (EAE), it also disrupts thymocyte development, which could lead to lethal thymic lymphoma. Here we identified a two-amino-acid substitution in RORγt (RORγt^M) that 'preferentially' disrupted T_H17 differentiation but not thymocyte development. Mice expressing RORγt^M were resistant to EAE associated with defective T_H17 differentiation but maintained normal thymocyte development and normal lymph-node genesis, except for Peyer's patches. RORγt^M showed less ubiquitination at Lys69 that was selectively required for T_H17 differentiation but not T cell development. This study will inform the development of treatments that selectively target T_H17 cell-mediated autoimmunity but do not affect thymocyte development or induce lymphoma.