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Fig. 5.
Adprhl1 morpholino embryos at stage 34, prior to overt cardiac phenotype.A, B, E-H: The heart of a stage 34 embryo injected with Adprhl1-e2i2MO into D-2/4 blastomeres, before the cardiac phenotype becomes apparent. Expression of myl7 in the myocardium and mpo in migrating embryonic macrophages are shown in left lateral (A) and ventral (B) views. The red lines (B) mark the position of four transverse sections cut through the heart outflow (E), ventricle (F), atrial (G) and inflow regions (H). C, D, I-L: Comparable images of a sibling embryo. In this experiment, half the cohort of injected embryos were allowed to develop on to stage 40 to confirm the morpholino’s subsequent action on heart formation and function. The macrophage marker was included to prove that impaired endocardial development noted at later stages did not originate from defective macrophage migration from the heart-forming region. Stage 33-34 marks the onset of cardiac contractions in control embryos. The only difference noted in morpholino injected embryos was within the outflow region, which did not extend rostrally but rather occupied a dorsal position. Scale bars = 100 μm. H, heart; M, macrophage; Sp, section position; Mc, myocardium; Ec, endocardium; Lv, liver. |