Figure 11

A hypothetic model for PICH function in Tat trans -activation. (A) A highly simplified schema illustrating the coupling of pre-initiation complex (PIC) dynamics with transcriptional elongation. On the wild type HIV core promoter nascent TAR RNA contacts PICH to increase the rate of dissociation of PICH-2 (upward green arrow), thereby increasing the rates of the subsequent cycle of PICH formation and potentially Pol II escape. (B) In contrast, on core promoters lacking functional CTGC motifs, aberrant complexes (aPIC), containing AP4, are slow to dissociate (upward red arrow) and TAR has no impact on them (see text for details).