(lanes 3-5) of Vero 76 cytosol immunoprecipitated with MBP antibody. Note lack of
immunoprecipitation from cell extract alone in lane 5. (D) RNA gel-shift assay with nonphosphorylated MBP and Cal-MBP in the absence of
cytosolic extracts (lanes 1 and 2), binding with phosphorylated MBP and Cal-MBP in the absence (lanes 3 and 4) and presence (lanes 5 and 6)
of cytosolic extract and with phosphorylated Cal-MBP fusion protein treated with alkaline phosphatase (lane 7). (E) RNA gel retardation assay
of RV SL RNA probe with the in vitro-phosphorylated proteins MBP (lane 1) and recombinant calreticulin (lane 2) and in the presence of
unlabeled 3' (+)-SL RNA (lane 3) and unlabeled 3' SL (AU) RNA (lane 4).