Fig 2: PTBP1 deficiency increases the inclusion of Tnik exon 14 and alters TNIK protein distribution. (A, B) PCR-based splicing assays show the splicing patterns of Tnik exon 14 at different ages. Representative gel images in A show exon 14-included and -excluded Tnik isoforms in the testes at different ages. Quantifications of PSI are shown in (B). Three Ptbp1ΔSC mice and three sibling littermate Ptbp1fl/fl mice were assessed at each age. Data are presented as mean\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} $ \pm$\end{document} SD, n = 3. **P< 0.01, ***P< 0.001, ****P< 0.0001. ns, not significant. (C) Double immunofluorescence staining using antibodies against TNIK and TUBB3 shows TNIK expression in the Sertoli cell cytoplasm. Boxed regions were magnified in the right panels. (D) Double immunofluorescence staining using antibodies against TNIK and ESPN shows TNIK expression in the apical ES (blue boxes) and basal ES (yellow boxes). Boxed regions are magnified in insets. PTBP1 deficiency altered TNIK distribution at both the apical ES (arrowheads) and basal ES (arrows).

Fig 3: PTBP1 deficiency induces aberrant splicing of Sertoli cell-enriched actin regulators. (A) The heatmap shows the PSI values of exons in 8 actin regulators enriched in Sertoli cells. (B, C) PCR-based splicing assays validate 5 alternatively spliced events in 5 actin regulatory genes in the testes of Ptbp1fl/fl and Ptbp1ΔSC mice at P35. Representative gel images are shown in B, and the quantifications of PSI are shown in C. 3 Ptbp1ΔSC mice and 3 sibling littermate Ptbp1fl/fl mice were assessed. Data are presented as mean\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} $ \pm$\end{document} SD, n = 3. *P< 0.05, **P< 0.01, ***P< 0.001.

Fig 4: Polypyrimidine tract binding protein 1 (PTBP1) contributed to transforming growth factor‐β1 (TGF‐β1)‐induced collagen accumulation and proliferation of cardiac fibroblasts (CFs). CFs were transfected with oe‐PTBP1 or si‐PTBP1. (A) Quantitative real‐time PCR analysis of PTBP1 level in CFs with various transfections. (B) The protein abundance of PTBP1, collagen I, and collagen III was detected by western blotting. (C) 5‐Ethynyl‐2′‐deoxyuridine (EdU) proliferation assay was utilized to determine proliferative ability of CFs (N = 3). DAPI, 4′,6‐diamidino‐2‐phenylindole; GAPDH, glyceraldehyde 3‐phosphate dehydrogenase. **P < 0.01, ***P < 0.001.

Fig 5: Schematic of the proposed mechanism of action of PTBP1 in ferroptosis in liver cancer cells. PTBP1, polypyrimidine tract-binding protein 1; NCOA4, nuclear receptor coactivator 4: ROS, reacitve oxygen species.