An NF-κB and Slug Regulatory Loop Active in Early Vertebrate Mesoderm
Panel A is a comparison of the Slug morpholino sequence (“MO”) with X. laevis SlugA, SlugB, and Snail RNA sequences; start codons are underlined. B–G: Injection of the Slug MO (10 ng/embryo) blocks the expression of Xbra (B-uninjected, C-Slug MO injected), Xmenf (D-uninjected, E-injected), and Antipodean (Apod)(F-uninjected, G-injected). Arrows (C,E,G) point to region of suppression; vegetal pole (“VP”) is indicated. In G, the red staining is due to a β-galactosidase lineage marker. H: Injection of the Slug MO into one cell of a two cell embryo blocks the expression of Sox9 on the injected side (arrow); “*” marks otic placode domain of Sox9 expression. I: Sox9 expression in Slug MO injected embryos is rescued by co-injection of mycGFP-Slug RNA (650 pg/embryo). In analogous studies, the effects of the Slug MO (10 ng/embryo) on Xbra (J), Apod (K) and Sox9 (L) expression were rescued by injection of Snail RNA (500 pg/embryo). In H, I and L, the line marks midline of the embryo, with anterior (“An”) and posterior (“Ps”) indicated.