Figure 3

Tax1(225-232) is involved in the p100 processing. (A) Amino acid sequence of Tax1(225-243) and Tax2B(225-243). The exchanged amino acids in the respective mutants and leucine residues putatively constituting the leucine zipper (LZ) structure are indicated. (B) Tax1^225-232, Tax1^225-227, and Tax1^231-232 have amino acid substitutions derived from Tax2B in the indicated regions in the backbone of Tax1. Jurkat cells were infected with lentiviruses encoding the indicated Tax or the mutant proteins. The total cell lysate (B), the cytoplasmic and the nuclear lysates (C) were prepared 48 hours after infection, and the amounts of p100, p52, Tax, α-Tubulin, and Sp1 in the lysates were measured by Western blotting analysis using anti-p100, anti-Tax1, anti-α-Tubulin or anti-Sp1 antibodies. The infection was normalized by EGFP expression on FACS analysis, and the infection level (%) was indicated.