Fig 4.

The effect of CypB over-expression is distinct from CypA. (A) Over-expression studies of CypA. Experiments were performed as described in Fig. 1 using a FLAG-tagged CypA expression vector. Results are normalized to results from cells transfected with an empty vector. (B) CsA does not abrogate the ability of CypB to enhance infection. Cells were pretransfected for 24 h with empty vector, CypA, or CypB then pretreated with CsA 2 h prior to infection with HIV-Luc VSVg. Cells were harvested and Luc activity measured to quantify infection (normalized to total protein). Presented results are normalized to control DMSO treated cells; * = p<0.01 by two-tailed t-test. Cell lysates were blotted for CypB and CypA expression using antibodies as indicated. GAPDH was used as loading control (bottom panels). (C) CsA induction of CypB secretion. 293T cells were treated with indicated concentrations of CsA for 48 h. Media and cell lysates were collected and the levels of CypB detected by immunoblot. Actin was detected as a loading control.