Figure 3. Hox and TALE members form protein complexes in vivo.
(A) NvPbx interacts with NvMeis in vivo. The nuclear localisation of a fusion mCherry-NvPbx protein was only observed upon co-injection with NvMeis. Graphs on the left are quantifications of the ratio between nuclear and cytoplasmic fluorescent signals (log2). Note that mCherry-NvPbx alone did not lead to any signal, suggesting that the fusion protein is not stable in the absence of Meis, as noticed in bilaterians. (B) BiFC between NvPbx and NvMeis in the Nematostella embryo. Fusion constructs are schematized on the left. VN: N-terminal fragment of Venus; VC: C-terminal fragment of Venus. Specificity of BiFC is verified by the absence of fluorescent signals upon the injection of isolated VN or VC fragments, together or with the complementary VC-NvMeis or VN-NvPbx fusion proteins, as indicated. Interaction between NvPbx and NvMeis occurs both in the cytoplasm and nucleus (see text for details). (C) BiFC between NvHoxE and NvPbx in the Nematostella embryo. Interaction occurs only in the nucleus. Mutation of the residue 54 in the homeodomain (HD) of NvPbx abolishes DNA-binding and BiFC with NvHoxE. In all panels, Dapi (cyan) stains nuclei and Dextran (red) is a control of injection conditions.