A number of factors in host cells have been implicated to be involved in the early and late phases of HIV-1 infection; e.g., CD4 as the major receptor for HIV-1 entry (Maddon et al., 1985; Lores et al., 1992), chemokine receptors as coreceptors (Berson et al., 1996; Feng et al., 1996) and cyclin T1 (CycT1) for the efficient viral transcription through binding to HIV-1 Tat (Bieniasz et al., 1998; Wei et al., 1998). Here, CCNT1 is linked to HIV-1 infection.