Fig. 2. TBX5 depletion results in dramatic upregulation of proteins associated with G₁/S-phase within the heart. (A) Expression profile of cell-cycle associated proteins, as determined by western blot analysis performed using lysate from either whole stage 33 embryos (emb), or corresponding heart tissue (heart). (B) Relative differences in embryonic cardiac CDK and cyclin proteins between CMO- and T5MO-derived heart tissue (stage 33). Note increased levels of Cyclin E2, CDC6, CDK2. (C) Relative differences in embryonic cardiac S-phase associated proteins SLBP and PCNA between CMO- and T5MO-derived heart tissue (stage 33). Colored bars denote the stage of the cell cycle at which the proteins are expressed, as indicated in the key.