Fig. 1. Characterization of XRnf12. (A) Amino acid sequence alignment of XRnf12, XRnf12B, and XRnf12C, as well as mouse and chick Rnf12. Note the repetitive heptamers present in XRnf12B and XRnf12C. A PDZ domain-binding motif is present in the C terminus. NLS, nuclear localization signal; asterisks, sites of mutation in the RING mutant XRnf12(HC>AA). DDBJ Accession Numbers are: XRnf12 (AB114039), XRnf12B (AB114040) and XRnf12C (AB114041). (B) Schematic representation of mRnf12, XRnf12, XRnf12B, and XRnf12C. (C) The N-terminal region (aa 1-283) of XRnf12 interacts with LIM homeodomain proteins and Ldb1. GST pull-down assay was performed with ³⁵S-labeled Xlim-1, Xlim-3, Xlim-5, Ldb1 and Ldb1C. While GST XRnf12C interacts with all of the proteins tested, GST XRnf12N shows little interaction. GST and GST Ldb1 serves as negative and positive controls, respectively.