TAT and HIV-1 infection: Our prediction was that when HIV-1 infection occurred within a DRSC, viral Vif expression would eliminate the YFP-A3G reporter, while Tat and Rev expression would coordinately transactivate Gag-mCherry expression, resulting in an “ON/OFF” color-switch with loss of YFP-A3G and gain of Gag-mCherry [yielding a YFP(−)/mCherry(+) infected cell] (Fig. 1A).