Figure 6.

A hypothetical model that accounts for the effects of IRENE and oxidative stress on HIV-1 5′UTR IRES activity. The model proposes that WT IRENE maintains the IRES in a weakly active conformation, which is stabilized by the binding of a repressor cellular protein (rep). In the course of HIV-1 infection, a decrease in global protein synthesis would decrease the level of this repressor. IRENE could then interact with a stimulatory ITAF, whose expression or relocalization was induced by oxidative stress. Binding of this ITAF causes a conformational change and promotes a more active IRES conformation (see the text).