Cardiac BMP4 asymmetry is disturbed in laterality mutants. (A,C) Normally, BMP4 transcripts accumulate predominantly on the left side of the heart tube at the 22-somite stage. (B) At the same stage, Nkx2.5 expression in the heart is symmetric. In those mutant embryos in which the heart fails to jog, such as floating head (flh), BMP4 is more evenly distributed in the heart (D). Mutants with a higher incidence of right-jogged heart, such as iguana (igu), have a higher incidence of right-dominant cardiac BMP4 (E). All are dorsal view, anterior to the bottom of the panel. Lines mark the midline. L, embryo left.
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