Fig. 3

The hst mutation is a hypomorphic allele with regards to cardiac laterality. (a) tbx5a variants generated to perform the rescue experiments: a tbx5a full-length (tbx5a FL) version includes the whole N-terminal (N, black rectangle), T- (T, blue rectangle) and C-terminal (C, grey rectangle) domains; a heartstrings version (tbx5a hst) containing the whole N-terminal domain and T-domain and a truncated C-terminal domain; and a tbx5a severely truncated version (tbx5a trunc) that contains the whole N-terminal domain and a truncated T-domain. (b) Quantification of the rescue experiments (wt, left jog; phenotype, right and middle jog). A χ² statistic has been calculated to assess significant differences between groups (**p < 0.01, *p < 0.05). (c,d) Dorsal views with anterior towards the left of 26 hpf +/+ or +/hst (c) and hst mutant (d) embryos showing normal leftward jogging of the embryonic heart tube highlighted by myl7 expression.