Figure 7 : Model for nuclear entry of IN labeled PIC.

From: Dynamic Oligomerization of Integrase Orchestrates HIV Nuclear Entry

Figure 7

The early stages of the HIV replication cycle in an infected cell are shown. After infection of cells, WT IN (gray circle) and labeled IN (green circle) associated with reverse transcribed vDNA are imported into the nucleus assisted by TRN-SR2 as part of the pre-integration complex (PIC). Nuclear entry of the PIC requires loss of IN-eGFP and is inhibited when stable multimeric IN complexes are present. Stable multimeric complexes are formed when LEDGINs (blue circles) are present during the production of new virus. LEDGINs can bind to the polyprotein precursor containing IN or to the mature IN. When bound, LEDGINs enhance IN multimerization forming stable multimeric complexes and a block in nuclear import. Upon nuclear entry of functional complexes, LEDGF/p75 (red circle) binds to the IN complex, resulting in an oligomer with a higher FRET ratio, activated for efficient integration. When LEDGINs (blue circle) are present during PIC nuclear import, they compete with LEDGF/p75 for binding to IN. LEDGINs inhibit integration by preventing IN-LEDGF/p75 complex formation and enhancing IN oligomerization.