Abstract Mutations in the ZAP-70 gene that cause moderate attenuation of T cell receptor (TCR) signaling in mice, can result in autoimmune manifestations akin to rheumatoid arthritis (RA). Here, we characterized the single-cell gene expression profiles and TCR repertoires of conventional (Tconv) and regulatory (Treg) CD4+ T cells of arthritic (ZAC), poised (SKG) ZAP-70 mutant, and wild-type (WT) mice.