FIG. 2.

Overexpression of ATM enhances HIV-1 replication at a posttranscriptional level. (a) Overexpression of ATM does not affect Tat-mediated transcription from HIV-1 LTR. 293T cells (2 × 10⁴ cells) were cotransfected with the HIV-1-LTR-luciferase (HIV-1-LTR-Luc) reporter gene (100 ng), Tat-expressing plasmid (Tat101-FLAG) (100 ng), and/or ATM-expressing plasmid (200 ng). Twenty-four hours after transfection, luciferase activity in the cellular lysates was measured. Results from three independent experiments are shown, with error bars indicative of the standard deviations from the means. (b) Overexpression of ATM increases production of late viral proteins. 293T cells (2 × 10⁵ cells) were cotransfected with an HIV-1 molecular clone (1 μg) and an ATM-expressing or a control plasmid (2 μg). Three days after transfection, Western blotting of the cellular lysate was performed with anti-ATM, anti-p24 CA, anti-p17 MA, anti-Nef, or anti-Chk2 antibody. (c) Northern blot analysis of cytoplasmic RNA from 293T cells cotransfected with an HIV-1 molecular clone with or without an ATM-expressing plasmid. The loading control was rRNA (18S and 28S rRNA) stained with ethidium bromide.