(A,B) Section in situ hybridization in saline (NaCl)-treated control (A) and lithium chloride (LiCl)-treated age-matched E10 embryos illustrating Armh4 expression. Note, Armh4 is significantly upregulated within the LiCl-treated embryo SHF progenitors and OFT (arrows) and right ventricle cardiomyocytes (B), when compared to NaCl control (A). (C) Quantitative qPCR analysis of microdissected E10 hearts verified Armh4 mRNA levels are induced (1.73x fold) via LiCl treatment, when compared to NaCl treatment (open bar). Moreover, Tbx5 (FHF and SHF effector) and Osr1 (SHF effector and direct target of Tbx5) mRNA levels are also similarly upregulated in LiCl-treated but not in NaCl-treated control samples. Relatively, at this stage, Armh4 (25 cycles) is expressed at higher overall levels than Osr1 (27 cycles) and Tbx5 (31 cycles). Error bars represent sd (fold change). (D,E) Immunohistochemistry using anti-βCatenin antibody verified that LiCl-treatment (E) but not NaCl-treatment (D) results in β–catenin elevation. Scale bars: A,B=100μm; D,E=20μm. Abbreviations: a, atria; fore, foregut.