TAT and infection: Early in the infection, HIV-1 vRNA processing depends fully on the host spliceosome machinery and only the HIV-1 MS vRNAs are exported to the cytoplasm and translated into the early proteins Tat and Rev, while the larger HIV-1 SS and US vRNAs accumulate in the nucleus (Stoltzfus, 2009; Karn and Stoltzfus, 2012).