CCNF and HIV-1 infection: Cells harvested 72 h post-transfection showed silencing of cyclin F by two among the three shRNA constructs (shRNA1 and shRNA3) with simultaneous stabilization of Vif expression as compared with control (Fig. 4F), further strengthening the negative regulation of Vif by cyclin F. The sequences and clone IDs of the shRNA used are given under “Experimental Procedures.” Further, to understand the significance of cyclin F in the context of HIV-1 infection, we performed overexpression and knockdown of cyclin F in TZM-bl as well as CEM-GFP cells followed by 0.5 m.o.i. HIV-1 infection.