Fig. 1: Ddx61 condensate responses to cardiogenic stimuli.

A Schematic of BioID2 experiment. B Heat-map indicating affinity-captured protein level changes in cardiomyocytes after exposure to different cardiac mitogens. C Pathway analysis of cardiomyocyte proteins increased 1.5-fold or more during mitogen stimulus or heart regeneration (latter data from ref. ¹⁷). D Venn diagram of cardiomyocyte proteins increased 1.5-fold or more in each BioID2 context. E Immunofluorescence (IF) of sections of uninjured ventricles and those regenerating 14 days after ablation of ~50% of cardiomyocytes (dpi), indicating staining for Ddx61 and myosin heavy chain (MHC). Scale bars, 100 and 10 μm for insets. Quantification of size (F) and number (G) of Ddx61 puncta (later referred to as condensate cluster (cc)) per 0.01 mm² from sections of uninjured and regenerating hearts. One 100 x 100 μm area was measured per heart (as in Fig. S1H). n = 9 hearts per group. Mean ± S.E.M., two-sided Mann–Whitney U test. Quantification of size (H, J) and number (I, K) of Ddx61 puncta (later referred to as condensate cluster (cc)) from sections of Nrg1-overexpressing (H, I) or Vegfaa-overexpressing (J, K) hearts or controls. n = 10 hearts per group, three independent experiments. One 100 x 100 μm area was measured per heart. Mean ± S.E.M., two-sided Mann–Whitney U test. L IF of sections of 14 dpi ventricles, stained for EdU incorporation to detect cycling cells, as well as Ddx61 and MHC. Arrows, cardiomyocytes with high Ddx61 levels and positive for EdU. Arrowheads, cardiomyocytes labeled with EdU possessing low Ddx61 levels. High magnification views in i. and ii. Scale bar 100 and 10 μm for insets. M STED super resolution images of Ddx61-positive condensates from sections of uninjured or 14 dpi hearts. Image brightness was reduced in 14 dpi images, which conceals single Ddx61 condensates. Scale bar 100 nm. Three independent experiments. Source data are provided as a Source data file.