Absence of accessory genes in a divergent simian T-lymphotropic virus type 1 isolated from a bonnet macaque (Macaca radiata)

Philippe V Afonso,Ernst J Verschoor,Antoine Gessain,Zahra Fagrouch,Henk Niphuis,Willy Bogers,Martin Deijs,Lia Van Der Hoek,Gregory Gromowski

doi:10.1371/journal.pntd.0007521

Abstract

BackgroundPrimate T-lymphotropic viruses type 1 (PTLV-1) are complex retroviruses infecting both human (HTLV-1) and simian (STLV-1) hosts. They share common epidemiological, clinical and molecular features. In addition to the canonical gag, pol, env retroviral genes, PTLV-1 purportedly encodes regulatory (i.e. Tax, Rex, and HBZ) and accessory proteins (i.e. P12/8, P13, P30). The latter have been found essential for viral persistence in vivo.Methodology/Principal findingsWe have isolated a STLV-1 virus from a bonnet macaque (Macaca radiata–Mra18C9), a monkey from India. The complete sequence was obtained and phylogenetic analyses were performed. The Mra18C9 strain is highly divergent from the known PTLV-1 strains. Intriguingly, the Mra18C9 lacks the 3 accessory open reading frames. In order to determine if the absence of accessory proteins is specific to this particular strain, a comprehensive analysis of the complete PTLV-1 genomes available in Genbank was performed and found that the lack of one or many accessory ORF is common among PTLV-1.ConclusionThis study raises many questions regarding the actual nature, role and importance of accessory proteins in the PTLV-1 biology.

Highlights

The Primate T-lymphotropic virus type 1 (PTLV-1) constitutes a group of deltaretroviruses infecting humans (HTLV-1) or non-human primates (STLV-1)
Viruses belonging to the African Primate T-lymphotropic viruses type 1 (PTLV-1) subtypes are found both in humans and non-human primates (NHPs), and the human and simian strains are undistinguishable
Two subtypes are exclusively human: PTLV-1a is found in human populations scattered throughout the globe, while PTLV-1c is found in indigenous people of the Australomelanesian continent

Summary

Introduction

The Primate T-lymphotropic virus type 1 (PTLV-1) constitutes a group of deltaretroviruses infecting humans (HTLV-1) or non-human primates (STLV-1). A group of STLV-1 has been described in macaques and great apes in Asia [5,6,7] These viruses are genetically distant from other subtypes (a fact that led some researchers to consider some of them as a separate STLV, STLV-5) [8] and have never been found in humans to date. Primate T-lymphotropic viruses type 1 (PTLV-1) are complex retroviruses infecting both human (HTLV-1) and simian (STLV-1) hosts. They share common epidemiological, clinical and molecular features. In addition to the canonical gag, pol, env retroviral genes, PTLV-1 purportedly encodes regulatory (i.e. Tax, Rex, and HBZ) and accessory proteins (i.e. P12/8, P13, P30) The latter have been found essential for viral persistence in vivo

Methods

Results

Conclusion