Viral Determinants of Integration Site Preferences of Simian Immunodeficiency Virus-Based Vectors

Abstract
Preferential integration into transcriptionally active regions of genomes has been observed for retroviral vectors based on gamma-retroviruses and lentiviruses. However, differences in the integration site preferences were detected, which might be explained by differences in viral components of the preintegration complexes. Viral determinants of integration site preferences have not been defined. Therefore, integration sites of simian immunodeficiency virus (SIV)-based vectors produced in the absence of accessory genes or lacking promoter and enhancer elements were compared. Similar integration patterns for the different SIV vectors indicate that vif , vpr , vpx , nef , env , and promoter or enhancer elements are not required for preferential integration of SIV into transcriptionally active regions of genomes.