Figure 7
From: Generation and characterization of a SIVmac239 clone corrected at four suboptimal nucleotides
Model of tRNA-mediated mismatched integration of the PBS following viral reverse transcription. Proposed model of the method by which the mismatched pairing in the primer binding site is generated and integrated into the host genome. The tRNA 3Lys binds the viral PBS and functions as a primer for the initiation of RT but retains a mismatched base to wild type SIVmac239 with a guanine to uracil (G/U) pairing. Reverse transcription progresses with the tRNA-primed U5 region disassociating from the viral RNA PBS, and reannealing to its 3′ end and continuing transcription through the PBS. Following complete RNAseH digestion of the parental RNA (except the PPT, which subsequently acts as a reverse primer for RT), the nascent double stranded DNA circularizes and uses itself as template to complete transcription. Integration of the resulting double stranded viral DNA occurs with a mismatched base containing cytosine and adenine (C/A) at position 860 of the PBS. The base is generated from the primer is a C (green) and the suboptimal base is retained as an A (blue) on antisense strand which encodes a T in viral progeny. Length of viral genome not drawn to scale.