FIGURE 1.
USP22 is induced as ESCs differentiate. E14 (A) and R1 (B) mouse ESCs grown in 2i/LIF medium were differentiated in 400-cell hanging drop EBs over the course of 12 days. Pluripotent ESCs were harvested at day 0 from 2i/LIF medium, and EBs were harvested at days 3, 6, 9, and 12 from medium without 2i/LIF. USP22, SOX2, and OCT4 protein expression was analyzed by Western blotting. qRT-PCR was used to define levels of USP22 mRNA during EB-induced differentiation. *, p < 0.05. C, E14 ESCs were withdrawn from 2i/LIF-conditioned medium and treated with 0.2 μm RA. Whole cell lysate was harvested before the removal of 2i/LIF and following 2, 3, 4, and 5 days of RA treatment, and USP22, SOX2, and ACTIN protein levels were analyzed by Western blotting (top panels). USP22 and SOX2 protein levels were quantified and normalized to ACTIN (bottom). Error bars, S.D.