FIG. 4.

Identification of phosphorylation site of BDV X. (A) HeLa cells infected with vTF7-3 were transfected with mock plasmid (lanes 1 and 5), ptfX (lanes 2 and 6), ptfP (lanes 3 and 7), and ptfP' (lanes 4 and 8) and were then labeled with [³⁵S]methionine (lanes 1 to 4) or [³²P]phosphate (lanes 5 to 8). The cell lysates were immunoprecipitated with anti-P (lanes 1, 3, and 4) or -X (lanes 2 and 6) antibody. (B) Construction of deletion or substitution mutants of potential phosphorylation sites of BDV X. (C) HeLa cells infected with vTF7-3 were transfected with X expression plasmid, and the cell lysates were immunoprecipitated with anti-FLAG antibody. Lanes: 1, mock; 2, ptfX; 3, ptfX^Δ3/16; 4, ptfX^T8A; 5, ptfX^S34A; and 6, ptfX^T37A.