(A) Heatmaps show autoantibody microarray data from sera of 12-week-old WT and Srsf1-cKO mice (n = 3 each) and 1 MRL/lpr mouse, analyzed for IgG reactivity against a 128-autoantigen panel. (B) Spleen images from aged (12- to 18-month-old) WT and Srsf1-cKO mice. Data are representative of at least 4 independent experiments. (C) Flow cytometry plots and graphs show Ki67 staining on live-gated CD4+ and CD8+ T cells from spleen of WT and Srsf1-cKO mice (2- to 18-month-old, n = 11 [WT], n = 8 [KO]). (D) Representative light microscopy images of H&E-stained paraffin sections of kidneys from aged (9- to 18-month-old) mice. Original magnification ×40. Arrows represent mesangial and endocapillary proliferation (upper) and interstitial inflammatory cell infiltration (lower). (E) Graph shows semiquantitative scores for kidney histopathology (n = 12 [WT], n = 9 [KO]). (F) Graph shows proteinuria from WT and Srsf1-cKO mice (n = 7 each). Mann-Whitney U test (E); unpaired t test (C and F); *P < 0.05, ***P < 0.005.