MYL7 and cardiac hypertrophy: To further investigate whether cardiac hypertrophy contributes to the thickening of the hos ventricle, we measured the CM size of wt and hos crossed with Tg (myl7:mCherry.nls; -minUnc45b:EGFP_CAAX) transgenic fish, in which the nuclei and cell membranes of the CM are labeled mCherry and EGFP, respectively (Figure 2A).