Anti-viral activity of the PAF1 complex. 4A CDC73, CTR9, LEO1, PAF1 and RTF1 siRNA knockdown rescues infection of HeLa-CD4 cells by HIV89.6R pseudotype. CDC73 and LEO1 were additionally deconvoluted and 4/4 and 3/4 siRNA respectively were able to rescue HIV-189.6R infection in HeLa-CD4 cells. The y-axis denotes both the number of infectious viruses rescued (FFU/ml; left) and fold rescue compared with the CB control (right). FFU/ml results are mean ± SD. 4B PAF1c siRNA knockdown rescues infection of HeLa-CD4 cells by replication competent HIV-189.6wt and HIV-1NL4.3wt (MOI 0.7). FFU/ml results are mean ± SD. 4C Knockdown of PAF1 and CTR9 rescues HIV-2CBL-21, HIV-2MCR, SIVAGM (African Green Monkey; 3084), SIVMAC (Macaque; 32H) and SIVSM (Sooty Mangabey; B670) infection. Results are fold increase compared with CB and are mean ± SD of at least 3 representative experiments. 4D Knockdown of PAF1, CTR9 and RTF1 in MM1 cells results in rescue of HIV-1 infection of replication competent HIV-189.6wt. Results are mean ± SD of a representative experiment. Transfection of MM1 cells with PAF1 siRNA results in partial knockdown. 4E Western blot analysis of primary cell lysates (CD4+ T cells, monocytes and macrophages (MDM)) showing protein levels of PAF1.