Identification of conserved lentiviral sequences as landmarks of genomic flexibility

Abstract

Considering that recombinations produce quasispecies in lentivirus spreading, we identified and localized highly conserved sequences that may play an important role in viral ontology. Comparison of entire genomes, including 237 human, simian and non-primate mammal lentiviruses and 103 negative control viruses, led to identify 28 Conserved Lentiviral Sequences (CLSs). They were located mainly in the structural genes forming hot spots particularly in the gag and pol genes and to a lesser extent in LTRs and regulatory genes. The CLS pattern was the same throughout the different HIV-1 subtypes, except for some HIV-1-O strains. Only CLS 3 and 4 were detected in both negative control HTLV-1 oncornaviruses and D-particle-forming simian viruses, which are not immunodeficiency inducers and display a genetic stability. CLSs divided the virus genomes into domains allowing us to distinguish sequence families leading to the notion of 'species self' besides that of 'lentiviral self'. Most of acutely localized CLSs in HIV-1s (82%) corresponded to wide recombination segments being currently reported.

The Remarkable Frequency of Human Immunodeficiency Virus Type 1 Genetic Recombination

“…In contrast, selection for maintaining essential features in viral genomes dictates that naturally arising variation can be more clustered. Examinations of crossovers in infectious virus in culture revealed that localized homology was a key factor (21,22,197,214). Previously reported recombination between significantly different strains may arise essentially by chance, may rely on residual homology or homology-independent recombination triggers, or may be disproportionately common in short regions of high donor/ acceptor template sequence identity (249,265,316).…”