CD4 and Arthritis: To understand the transcriptional profile of these SKGNur GFPhi cells, we performed bulk RNA-Seq on naive (CD62LhiCD44loCD25–) CD4+ T cells with the highest (GFPhi) and lowest (GFPlo) GFP expression; these cells were obtained from SKGNur and WT (WTNur) mice before arthritis onset (Figure 1A, Supplemental Figure 1B, and Supplemental Data File 1).