Fig 1

natter/fn1a^tl43c mutants display a variable cardiac phenotype.

(A)In situ hybridisation with the myocardial marker myl7 was performed on 24 hpf natter/fn1a^tl43c mutant embryos and WT siblings from four single pair natter/fn1a^tl43c heterozygous intercrosses. The proportion of embryos matching the image shown is indicated in the top right corner of each image. The remaining 6/41 mutant embryos displayed a linear heart tube phenotype as noted in (B). Dorsal views are shown with anterior to the top. (B) Quantification of the 24 hpf myocardial migration phenotype in natter/fn1a^tl43c mutants and WT siblings shown in (A). (C) Representative images of a 100 hpf homozygous WT sibling as well as a WT-like, a mild, and a severe natter/fn1a^tl43c mutant larva from a single pair natter/fn1a^tl43c heterozygous intercross. Lateral views are shown with anterior to the left. The mild mutant phenotype is distinguishable by mild pericardial oedema (white arrowhead). The severe mutant phenotype is distinguishable by a small head, pronounced pericardial oedema, and disorganised trunk muscle fibres (white arrows). (D) Confocal images of three hearts representative of each phenotype were selected from imaging 12 WT-like, 6 mild, and 6 severe Tg(myl7:EGFP) mutants from a single pair natter/fn1a^tl43c mutant incross at 100 hpf. For the fn1a^+/+ and fn1a^+/tl43c siblings, referred to collectively as fn1a^+/?, three representative images were selected from imaging 12 WT fn1a^+/? siblings from a single pair natter/fn1a^tl43c heterozygous intercross at 100 hpf. (E) Quantification of the 100 hpf cardiac phenotype in natter/fn1a^tl43c mutants and WT siblings from three single pair natter/fn1a^tl43c heterozygous intercrosses. The numbers on each bar in (B) and (E) indicate the total number of larvae assessed. All p-values were calculated using chi-squared tests. Scale bars, 100 µm in (A) and (D), and 1 mm in (C).