|
Fig. 2.
Injection of PRDM12 mRNA inhibits neural crest formation via trimethylation of histone H3K9. (A) The PRDM12 protein structure showing a PR/SET domain (black box) and multiple zinc-finger domains (gray boxes). (B) A control embryo at stage 38. (C) An embryo injected with PRDM12 mRNA (1000 pg/embryos) into the animal pole at the two-cell stage showing the small head and pigmentation defects. (D–O) WISH analysis of expressed transcripts at the mid-neurula stage, with anterior views of each embryo. (D–I) The expression of neural crest markers (Foxd3, Slug, and Sox9) was diminished in embryos injected with PRDM12 mRNA (1000 pg/embryo) at the two-cell stage. In contrast, (J–O) the expression of the presumptive trigeminal placode (Islet1), early pan-placode (Six1), and neural marker (Sox2) remained largely unchanged. (P) RT-PCR analysis showed that expression of the neural crest markers was decreased in a dose-dependent manner by injection of PRDM12 mRNA into Chd and Wnt8 mRNA-injected animal caps. (Q) Western blot analysis with antibodies against trimethylated histones H3K4, H3K9, H3K27, and H3 on samples of Chd and Wnt8 mRNA-injected animal cap cells, with and without PRDM12 mRNA. The scale bars for B and C, and D–O, represent 1 mm and 0.5 mm, respectively. |