Figure 9. Interaction properties of Hox and TALE proteins from Trichoplax adhaerens and Acanthamoeba castellanii.
(A) The ProtoHox/ParaHox Trox2 protein from Trichoplax adhaerens does not form DNA-binding complexes with PBC or PBC/Meis in vitro. Band shift experiments are performed with mouse Pbx (MmP) and Meis (MmM) proteins on central (Meis-II) and posterior (Meis-III) Hox/PBC/Meis binding sites as indicated. Black arrowhead shows dimeric Pbx/Meis complexes. (B–D′) PBC (AcP) and Meis (AcM) proteins from the unicellular Acanthamoeba castellanii organism cannot form protein complexes between each other or with Hox proteins. (B) Band shift experiment on a consensus PBC binding site (PRS, Chang et al., 1995). AcP does not bind DNA, neither as a monomer nor with AcM. A weak monomer DNA-binding of AcM is observed (white arrowhead). This monomer binding is strongly enhanced in the presence of mouse Pbx1 (MmP, black arrowhead). In comparison, MmP binds strongly (grey arrow), and the monomer binding of Meis1 (MmM) is also strongly enhanced in the presence of Pbx1 (black arrow). (C–C′) Band shift experiments with mouse HoxB8 (MmHoxB8) and mouse or Acanthamoeba TALE cofactors on the central (Meis-II) Hox consensus binding probe as indicated. (D–D′) Band shift experiments with mouse HoxA9 (MmHoxA9) and mouse or Acanthamoeba TALE cofactors on the posterior (Meis-III) Hox consensus binding probe as indicated. Complexes with Hox proteins are observed only with mouse Pbx (grey arrows) and Pbx/Meis partners (black arrows) on both probes. AcPbx and AcMeis proteins are not able to form dimeric complexes on these probes, unlike mouse TALE proteins (black arrowheads). See also Figure 9—figure supplement 1.
Figure 9—figure supplement 1. PBC and Meis proteins from the unicellular Acanthamoeba castellanii organism do not form protein complexes with mouse HX-mutated Hox proteins.
