FIG. 4.

ATM effect is specific to Rev-dependent gene expression. (a) 293T cells (2 × 10⁵ cells) were cotransfected with the Rev/RRE-dependent gag-pol construct pCMV R8.91, the Rev-independent codon-optimized HIV-1 gag-pol construct pSYNGP, or an HIV-1 gag-pol construct containing four tandem copies of the Mason-Pfizer monkey virus CTE, pGPV-4×CTE (2 μg), as well as ATM-expressing or empty vectors (2 μg). Three days after transfection, Western blotting of the cellular lysate was performed with anti-p24 CA or anti-Chk2 antibody, and p24 levels in the supernatant were measured by ELISA. (b) Overexpression of ATM increases HIV-1 p24 only in the presence of Rev. 293T cells were cotransfected with an RRE-containing HIV-1 gag-pol construct (pGPV-RRE) (2 μg), a Rev-expressing plasmid (1 μg), and/or an ATM-expressing plasmid (2 μg). Western blotting was performed as described for panel a. (c) Overexpression of ATM does not affect HTLV-1 Rex function. 293T cells were cotransfected with the HTLV-1 molecular clone λHTLV-1C or K30p (2 μg) with or without an ATM-expressing plasmid (2 μg). Three days after transfection, Western blotting of the cellular lysate was performed with anti-HTLV-1 p24 or anti-Chk2 antibody. C, control.