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Figure 3.
XREST/NRSF loss of function induces expansion of neural tissue. A, Transversal sections (a–c, e–g), dorsal (d, h–j, m–t) and anterior (k, l) views of neural plate stage embryos injected with 500 pg of in vitro transcribed dnXREST mRNA or 5 pmol of MoXREST (indicated on top). Probes used for ISH are indicated to the left of each row. Embryos injected with MoXREST or with dnXREST and induced at late blastula [Dex(+) st. 9] exhibit expansion of the neural markers SoxD and Sox2 (a–h, brackets) and a diminished expression of epidermal keratin (j, l), msx-1 (n, p), and Slug (r, t) (arrows). Less severe effects are observed in embryos induced at late gastrula: SoxD (c), Sox2 (g), keratin (k), msx-1 (o) and Slug (s). Dex(+) st. 12, Embryos exposed to dexamethasone at stage 12. B, Anterior views of stage 18 embryos injected with 200 pg of dnXREST (a, b, e, f) or in combination with 1 ng of XREST/NRSF in one cell at the 2-cell stage (c, d, g, h) (indicated on top). Embryos injected with dnXREST induced at stage 9 exhibit enlargement of anterior neural plate, marked by Sox2 expression (b, arrows) and the lateral displacement and loss of keratin expression (f, arrows). Non-induced dnXREST/XREST embryos do not display noticeable defects (c, g). dnXREST/XREST embryos induced at stage 9 do not display an expanded domain of Sox2 expression (d) and decreased keratin expression (arrows). |
