Fig. 4

Ubiquitous YY1a inhibition by injection of morpholinos (YY1-MO). a Western-blot analysis of YY1a proteins in the 24-h stage wild type embryos and YY1-MO-injected embryos. The knockdown of YY1a gene in these embryos by YY1-MO injection was shown in panel a, lane 3 (panel a, lanes 1–3; panel b, the positive control, HeLa cell lysate). Actin was the loading control. b Each one-cell stage embryo was injected with either 25 ng of control-MO or 25 ng of YY1-MO. At 12, 24, and 48 hpf, embryos were fixed and examined after in-situ hybridization. The phase-contrast images of the wild type (panels, a, d, and g) and control-MO-injected (panels b, e, and h) embryos show normal development and YY1a expression patterns. However those of the YY1-MO-injected embryos show abnormal development (panels c, f and i) and delayed YY1a expression (panel c, 12 hpf; arrows) and abnormal YY1a expression (panel f and i; 24 and 48 hpf, respectively; arrows). c Phase-contrast images of wild type embryos (panel a), control-MO-injected embryos (panel b), YY1-MO-injected embryos that are slightly affected (panel c), and YY1-MO injected embryos that are severely affected (panel c). The abnormal brain and heart are indicated by arrows. Bars indicate 250 μm