Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants

Around 8% of the human genome comprises Human Endogenous Retroviruses (HERVs) acquired over primate evolution. Some are specific to primates such as HERV-K, consisting of 10 HML subtypes and including the most recently acquired elements. Particularly, HML2 is the youngest clade, having some human-sp...

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Main Authors: Saili Chabukswar, Nicole Grandi, Enzo Tramontano
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-12-01
Series:Frontiers in Microbiology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2022.1040792/full
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author Saili Chabukswar
Nicole Grandi
Enzo Tramontano
author_facet Saili Chabukswar
Nicole Grandi
Enzo Tramontano
author_sort Saili Chabukswar
collection DOAJ
description Around 8% of the human genome comprises Human Endogenous Retroviruses (HERVs) acquired over primate evolution. Some are specific to primates such as HERV-K, consisting of 10 HML subtypes and including the most recently acquired elements. Particularly, HML2 is the youngest clade, having some human-specific integrations, and while it has been widely described in humans its presence and distribution in non-human primates remain poorly characterized. To investigate HML2 distribution in non-human primates, the present study focused on the characterization of HML2 integrations in Macaca fascicularis and Macaca mulatta which are the most evolutionarily distant species related to humans in the Catarrhini parvorder. We identified overall 208 HML2 proviruses for M. fascicularis (77) and M. mulatta (131). Among them, 46 proviruses are shared by the two species while the others are species specific. Only 12 proviruses were shared with humans, confirming that the major wave of HML2 diffusion in humans occurred after macaques’ divergence. Phylogenetic analysis confirmed structural variations between HML2 macaques’ species-specific proviruses, and the ones shared between macaques and humans. The HML2 loci were characterized in terms of structure, focusing on potential residual open reading frames (ORFs) for gag, pol, and env genes for the latter being reported to be expressed in human pathological conditions. The analysis identified highly conserved gag and pol genes, while the env genes had a very divergent nature. Of the 208 HML2 proviral sequences present in Macaca species, 81 sequences form a cluster having a MER11A, a characteristic HML8 LTR sequence, insertion in the env region indicating a recombination event that occurred between the HML2 env gene and the HML8 LTR. This recombination event, which was shown to be present only in a subset of macaques’ shared sequences and species-specific sequences, highlights a recent viral activity leading to the emergence of an env variant specific to the Old World Monkeys (OWMs). We performed an exhaustive analysis of HML2 in two species of OWMs, in terms of its evolutionary history, structural features, and potential residual coding capacity highlighting recent activity of HML2 in macaques that occurred after its split from the Catarrhini parvorder, leading to the emergence of viral variants, hence providing a better understanding of the endogenization and diffusion of HML2 along primate evolution.
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spelling doaj.art-f0cc2de51c294cd2a66fa229f3c325842022-12-22T04:16:20ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2022-12-011310.3389/fmicb.2022.10407921040792Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variantsSaili ChabukswarNicole GrandiEnzo TramontanoAround 8% of the human genome comprises Human Endogenous Retroviruses (HERVs) acquired over primate evolution. Some are specific to primates such as HERV-K, consisting of 10 HML subtypes and including the most recently acquired elements. Particularly, HML2 is the youngest clade, having some human-specific integrations, and while it has been widely described in humans its presence and distribution in non-human primates remain poorly characterized. To investigate HML2 distribution in non-human primates, the present study focused on the characterization of HML2 integrations in Macaca fascicularis and Macaca mulatta which are the most evolutionarily distant species related to humans in the Catarrhini parvorder. We identified overall 208 HML2 proviruses for M. fascicularis (77) and M. mulatta (131). Among them, 46 proviruses are shared by the two species while the others are species specific. Only 12 proviruses were shared with humans, confirming that the major wave of HML2 diffusion in humans occurred after macaques’ divergence. Phylogenetic analysis confirmed structural variations between HML2 macaques’ species-specific proviruses, and the ones shared between macaques and humans. The HML2 loci were characterized in terms of structure, focusing on potential residual open reading frames (ORFs) for gag, pol, and env genes for the latter being reported to be expressed in human pathological conditions. The analysis identified highly conserved gag and pol genes, while the env genes had a very divergent nature. Of the 208 HML2 proviral sequences present in Macaca species, 81 sequences form a cluster having a MER11A, a characteristic HML8 LTR sequence, insertion in the env region indicating a recombination event that occurred between the HML2 env gene and the HML8 LTR. This recombination event, which was shown to be present only in a subset of macaques’ shared sequences and species-specific sequences, highlights a recent viral activity leading to the emergence of an env variant specific to the Old World Monkeys (OWMs). We performed an exhaustive analysis of HML2 in two species of OWMs, in terms of its evolutionary history, structural features, and potential residual coding capacity highlighting recent activity of HML2 in macaques that occurred after its split from the Catarrhini parvorder, leading to the emergence of viral variants, hence providing a better understanding of the endogenization and diffusion of HML2 along primate evolution.https://www.frontiersin.org/articles/10.3389/fmicb.2022.1040792/fullHERV-KHML2Old World MonkeysMacacarecombinationHERV-K11
spellingShingle Saili Chabukswar
Nicole Grandi
Enzo Tramontano
Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
Frontiers in Microbiology
HERV-K
HML2
Old World Monkeys
Macaca
recombination
HERV-K11
title Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
title_full Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
title_fullStr Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
title_full_unstemmed Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
title_short Prolonged activity of HERV-K(HML2) in Old World Monkeys accounts for recent integrations and novel recombinant variants
title_sort prolonged activity of herv k hml2 in old world monkeys accounts for recent integrations and novel recombinant variants
topic HERV-K
HML2
Old World Monkeys
Macaca
recombination
HERV-K11
url https://www.frontiersin.org/articles/10.3389/fmicb.2022.1040792/full
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AT enzotramontano prolongedactivityofhervkhml2inoldworldmonkeysaccountsforrecentintegrationsandnovelrecombinantvariants