Figure 4

Calb2 subtype marker expression requires Sox14. RNA interference was used to downregulate expression of the endogenous Sox14 gene in the rTh. Four different sequences of the chick Sox14 mRNA were targeted (seq1 to 4); their effect in inducing Sox14 mRNA degradation was tested by transient co-transfection in cell culture or co-electroporation in the embryo. The Sox14i seq2 was used to obtain the data in A and B (A). Acute downregulation of Sox14 from E2.5 has no effect on the expression of rTh genes in the proliferative (Ascl1) and postmitotic (Tal1, Npy) domains, whilst a reduction of endogenous Sox14 mRNA is observed (B). Lack of Calb2 expression in the rTh expressing a Sox14i construct. Despite the strong downregulation of the subtype marker Calb2, no changes in expression of the panGABAergic marker GAD65/67 could be detected; this, together with the lack of any detectable effect on other pan- and rTh GABAergic transcription factors suggests a restricted role for Sox14 in controlling GABA neuron subtype specific gene expression (C). Scale bars: 100 μm.