Figure 1.
Domain structure of XErp1 and characterization of the XErp1 antibody. (A) The N terminus of XErp1 contains the putative SCFβ-TRCP recognition sequence DSGX3S. In addition, XErp1 protein contains a putative C-terminal F-box and a zinc-binding region (ZBR). The C terminus of XErp1 shares 39% sequence identity with Xenopus Emi1. (B) ClustalW alignment of XErp1 protein sequences from different vertebrate species shows the evolutionary conservation of the XErp1 proteins. The amino acid sequences of XErp1 peptides that were identified by LC-MS/MS analysis of XErp1 are indicated (solid blue lines, peptide sequences in agreement with both XErp1 and Fbx26 ORF; dashed blue lines, peptide sequences in agreement only with XErp1 ORF). (C) Characterization of XErp1 antibodies. CSF extract or in vitro translated (IVT) XErp1, IVT xEmi1, or unprogrammed wheat germ extract were immunoblotted with affinity purified anti-XErp1 antibodies (left) or with affinity-purified anti-XErp1 antibodies blocked with XErp1 antigen (right). (Middle) The expression level of the 35S-labeled IVT proteins was examined by autoradiographic analysis.