Fig. 7

Add3 functions cell-autonomously to affect F-actin localization. (A-C) Flattened z-stacks showing phalloidin (red) and anti-DM-GRASP (green) labeling of 48 hpf WT, MO¹⁴³ and MO^add3TP zebrafish cardiomyocytes within the OC. (D) The construct used to overexpress GFP and add3 (no 3′ UTR). (E,F) Cell circularity (E) and area (F) in mosaic hearts. Add3-overexpressing OC myocytes are statistically more circular (blue bar) than OC CMs labeled with GFP alone (green bar). ^*, P=0.00045. Error bars represent ± s.e.m. (G-N) Samples of the raw data used to generate the bar charts in E and F. Asterisks indicate GFP⁺ cells. (G-L) Head-on view of the ventricular OC. (M,N) Cross-section through the ventricle. (G) Merged confocal image showing WT GFP⁺ cells (green) and F-actin distribution (red). (H) Same image as in G but showing phalloidin staining alone. Abundant intracellular F-actin fibers can be seen in elongated GFP⁺ OC cells. (I,K,M) Merged confocal images showing add3-overexpressing GFP⁺ cells (green) and F-actin distribution (red). (J,L,N) The same images as in I,K,M but showing phalloidin staining alone. (I,J) Intracellular fibers are more visible in elongated WT cells than in add3-overexpressing neighbors (green). (K-N) Approximately half of the add3-overexpressing cells are extruded from the ventricular wall and show obvious cortical F-actin localization as compared with their WT (GFP^-) neighbors.