Fig. 4. GBP binds within the first 44 amino acids of XKLC4. (A) Schematic diagram of the XKLC4 deletion constructs. The wild-type (WT) protein is depicted on top, with the previously identified domains shown as boxes, and with numbers indicating the first and last amino acid residues of the domains. In the case of the heptad repeat-containing and TPR domain constructs, the numbers indicate the first and last residues of XKLC4 that are included. For XKLC4 1-4, the numbers indicate the residues flanking the deletions. (B) Xenopus embryos were injected at the 2-4-cell stage with GBP-myc and WT or mutant XKLC4-HA RNAs as indicated. After 4-5 hours the tagged proteins were immunoprecipitated with anti-HA antibody or anti-FLAG antibody as a negative control and detected by Western blotting with anti-HA and anti-myc antibodies (left panel). An aliquot of each sample was taken before immunoprecipitation to show relative expression levels of injected RNAs (total lysates, right panel). Note that the XKLC4-TPR construct runs with the Ig heavy chain from the antibody used in the immunoprecipitation. (C) Embryos were injected with GBP-myc RNA and WT or deletion mutant XKLC4-HA RNA as indicated and processed as in B.