Fig. 9

careg-expressing cells contribute to the regenerating myocardium and fin mesenchyme.

(a,b) Schematic representation of the transgenic strains and the experimental design for lineage tracing of careg-expressing primordial CMs during ventricle regeneration. (c–f) Representative sections of hearts treated with 4-OHT before cryoinjury to label the primordial layer, stained with antibody against Tropomyosin (blue). (c,d) At 10 d.p.ci., no zsYellow is detected in the trabecular myocardium at the injury site, indicating that primordial CMs do not contribute to the regeneration zone along the post-cryolesioned tissue. (e,f) At 30 d.p.ci., the zsYellow-positive primordial layer regenerates incompletely. (g) Experimental design for lineage tracing of careg-expressing dedifferentiated CMs during ventricle regeneration. (h–k) Representative sections of hearts treated with 4-OHT after cryoinjury hearts immunostained against Tropomyosin (blue) (h,i) At 15 d.p.ci., zsYellow is expressed in the trabecular myocardium at the injury site. (j,k). At 30 d.p.ci., zsYellow-positive CMs are detected in the trabecular (TrM) and cortical myocardium (CoM) of the regenerated muscle. N≥8. (l) Transgenic strains and the design of lineage tracing experiments during fin regeneration. (m) Longitudinal section of lineage-labelled fins at 3 d.p.a., stained for osteoblasts using the Zns5 antibody (green) and for nuclei with DAPI (blue). mCherry is detected in the entire mesenchyme of the regenerative outgrowth and below the amputation plane. N=6. (n–u) Live-imaging of the same lineage-labelled fin at different time points of regeneration. The regenerative outgrowth and the stump tissue are labelled with mCherry. N=6.