Expression pattern of maternal and zygotic MEF2.

<p>(A) Quantitative PCR analysis of MEF2A and MEF2D transcripts from fertilization to gastrula stages. Experiment was performed two independent times. (B) 4 cell embryos were analyzed by ISH using probes <i>to mef2a</i> and <i>mef2d</i>. (C) Left panels: Stage 8 embryos were dissected to animal and vegetal halves. RNA and proteins were extracted. RNA was analyzed by RT-PCR reaction and proteins by Western analysis. Right panel: Immunohistochemistry of stage 8 embryos. Animal-vegetal sections were prepared. Sections were reacted with anti-MEF2 antibodies (orange) and counterstained with hematoxylin. The right panel is an enlargement of a segment of the left panel. (D) Left panel: Hemisected stage 9 embryos were analyzed by ISH using probes <i>to mef2a and mef2d</i>. Right panel: Sections of stage 9 embryos were reacted with anti-MEF2 antibodies (orange) and counterstained with hematoxylin. The right end panel is an enlargement of a segment of the left panel. Arrows point at stained nuclei. (E) Left panel: Stage 10.5 embryos were analyzed by <i>in situ</i> hybridization using a probe <i>to mef2d</i>. Right panel: x3 Mef2-Luc reporter (30 pg) was injected to one cell embryo (20 embryos). At early gastrula stage (10.25), DMZ and VMZ explants were isolated and luciferase was measured. Luciferase activity was normalized to the total protein levels. Data are presented as means ± SE of three independent experiments.