Fig. 4

Fig. 4. Inhibition of Wnt/β-catenin signaling impairs cardiomyocyte proliferation. (A) PCNA and MEF2 immunostaining on cryoinjured hearts of hs:Axin1-YFP fish and wild-type siblings, heat-shocked daily from 1 to 7 dpi. n (hearts) ​= ​7 (wild-type), 8 (hs:Axin1-YFP). White arrowheads point to PCNA⁺MEF2⁺ cardiomyocytes. Scale bars, 100 ​μm (overview), 10 ​μm (magnification). (B) Quantification of the data shown in (A). Error bars represent CI 95%. Unpaired Welch's unequal variances t-test. (C) Quantification of PCNA⁺MEF2⁺/MEF2⁺ borderzone cardiomyocytes of cryoinjured hearts of hs:Axin1-YFP fish and wild-type siblings, heat-shocked (h.s.) at 6 dpi and harvested after 24 ​h at 7 dpi. n (hearts) ​= ​8 (wild-type), 9 (hs:Axin1-YFP). Error bars represent CI 95%. Unpaired Welch's unequal variances t-test. (D) PH3 and GFP immunostaining on 7 dpi myl7:H2B-GFP hearts. White arrowheads point to PH3⁺GFP⁺ cardiomyocytes. Scale bars, 100 ​μm (overview), 10 ​μm (magnification). (E) Quantification of PH3⁺GFP⁺/GFP⁺ borderzone cardiomyocytes of cryoinjured hearts of hs:Axin1-YFP, myl7:H2B-GFP fish and myl7:H2B-GFP siblings (wild-type for hs:Axin1-YFP), heat-shocked daily from 1 to 7 dpi and treated with nocodazole (abbreviated noco) in the last 24 ​h before harvesting at 7 dpi. n (hearts) ​= ​7 (wild-type), 8 (hs:Axin1-YFP). Error bars represent CI 95%. Unpaired Welch's unequal variances t-test. (F) Quantification of PCNA⁺MEF2⁺/MEF2⁺ borderzone cardiomyocytes of cryoinjured hearts from fish treated with DMSO or IWR1 from 1 to 7 dpi. Error bars represent CI 95%. n ​= ​8 (DMSO), 7 (IWR1). Unpaired Welch's unequal variances t-test.