| |
Figure 4. Inhibiting HCN4 function in different locations disrupts heart morphology. (A) Uninjected tadpoles have a clear chest cavity at NF stage 43/44, making the heart easily visible laterally (arrowhead, i). Hearts have normal ventricle and outflow tract morphology as seen via IHC for cardiac troponin-T antibody (ventral view, ii). The left eye is circled (white dashed line) in all images as a landmark. (B-D) HCN4-DN(AAA) injected embryos display a variety of heart defects, irrespective of the location of the lineage label membrane-bound RFP. Examples of tadpoles with mem-RFP located in the: heart (arrowhead, B, i), posterior flank (C, i), and dorsal region (D, i) of HCN4-DN(AAA) injected animals. White arrowheads denote position of heart. Ventral views of malformed heart phenotypes: symmetric midline hearts (B, ii), unlooped hearts (C, ii), and twisted hearts (D, ii). n = 18–31embryos per injection condition. Scale bars = 200 µm. |
