Fig. 2: Ddx61 is required for heart regeneration programs.

A Schematic of ddx6 locus. B Quantification of PCNA-positive cardiomyocytes in wild-type and ddx6-KO ventricles at 7 dpa. n = 10 hearts. Mean ± S.E.M., two-sided Mann–Whitney U test. C Schematic of ddx61 locus. D IF images of wild-type or ddx61-KO 7 dpa hearts stained for PCNA (green) and Mef2 (red). Scale bar = 100 μm. Three independent experiments. E Quantification of PCNA-positive cardiomyocytes (Mef2) in a 100 μm region at the resection site. n = 11 hearts. Mean ± S.E.M., two-sided Mann–Whitney U test. F IF (top) and AFOG staining (bottom) of 30 dpa wild-type and ddx61-KO ventricles. collagen (Col), fibrin (FN, muscle (Mus). Scale bar = 100 μm. G Semi-qualitative scoring of MHC-stained 30 dpa ventricles: complete (1), partial (2), blocked (3) regeneration. n = 13 hearts. Two-sided Fisher’s exact test. H IF images of wild-type or ddx61-KO ventricles with or without nrg1 overexpression (Nrg1-OE; WT lacks cmlc2:CreER, both groups treated with tamoxifen). Scale bar = 100 μm. I Quantification from (H). n = 11 hearts per group. Mean ± S.E.M., two-sided Mann–Whitney U test. J Quantification of cardiomyocyte cycling in wild-type or ddx61-KO ventricles with or without vegfaa overexpression (Vegfaa-OE). n = 11 hearts. Mean ± S.E.M., two-sided Mann–Whitney U test. K Proteome profiling workflow. L 1330 proteins were identified with a fold change >1.5. M Heatmap shows proteins with fold change >1.5 involved in cardiac development, differentiation, and remodeling. N IF of 7 dpa ventricles stained for Sm22 (green) and MHC (magenta). Scale bar = 100 μm. O Quantification of Sm22 from (N). n = 10 hearts. Mean ± S.E.M., two-sided Mann–Whitney U test. P Heatmap of proteins with fold change >1.5 linked to extracellular environment. Q IF of 7 dpa ventricles stained for Fn1 (green) and MHC (red). Right: rainbow scale for Fn1. Scale bar = 100 μm. R, S Quantification of Fn1 and Agrin levels. Western blots in Fig. S9F, H. n = 3 experiments. Mean ± S.E.M., unpaired two-sided t-test. Data are provided as Source data.