Simian immunodeficiency virus integration preference is similar to that of human immunodeficiency virus type 1

Simian immunodeficiency virus (SIV) is a useful model for studying human immunodeficiency virus (HIV) pathogenesis and vaccine efficacy. As with all other retroviruses, integration is a necessary step in the replication cycle of SIV. The location of the retrovirus integration site is known to impact on viral gene expression, establishment of viral latency, and other aspects of the replication cycle of a retrovirus. In this study, 148 SIV provirus integration sites were sequenced and mapped in the human genome. Our analysis showed that SIV integration, like that of HIV type 1 (HIV-1), exhibited a strong preference for actively transcribed regions in the genome (A. R. Schroder et al., Cell 110:521-529,2002) and no preference for the CpG islands or transcription start sites, in contrast to observations for murine leukemia virus (X. Wu et al., Science 300:1749-1751, 2003). The parallel integration target site preferences of SIV and HIV-1 suggest that these lentiviruses may share similar mechanisms for target site selection and that SIV serves as an accurate model of HIV-1 with respect to integration.