TY - JOUR
T1 - Degradation and remobilization of endogenous retroviruses by recombination during the earliest stages of a germ-line invasion
AU - Löber, Ulrike
AU - Hobbs, Matthew
AU - Dayaram, Anisha
AU - Tsangaras, Kyriakos
AU - Jones, Kiersten
AU - Alquezar-Planas, David E.
AU - Ishida, Yasuko
AU - Meers, Joanne
AU - Mayer, Jens
AU - Quedenau, Claudia
AU - Chen, Wei
AU - Johnson, Rebecca N.
AU - Timms, Peter
AU - Young, Paul R.
AU - Roca, Alfred L.
AU - Greenwood, Alex D.
N1 - Publisher Copyright:
© 2018 National Academy of Sciences. All Rights Reserved.
PY - 2018/8/21
Y1 - 2018/8/21
N2 - Endogenous retroviruses (ERVs) are proviral sequences that result from colonization of the host germ line by exogenous retroviruses. The majority of ERVs represent defective retroviral copies. However, for most ERVs, endogenization occurred millions of years ago, obscuring the stages by which ERVs become defective and the changes in both virus and host important to the process. The koala retrovirus, KoRV, only recently began invading the germ line of the koala (Phascolarctos cinereus), permitting analysis of retroviral endogenization on a prospective basis. Here, we report that recombination with host genomic elements disrupts retroviruses during the earliest stages of germ-line invasion. One type of recombinant, designated recKoRV1, was formed by recombination of KoRV with an older degraded retroelement. Many genomic copies of recKoRV1 were detected across koalas. The prevalence of recKoRV1 was higher in northern than in southern Australian koalas, as is the case for KoRV, with differences in recKoRV1 prevalence, but not KoRV prevalence, between inland and coastal New South Wales. At least 15 additional different recombination events between KoRV and the older endogenous retroelement generated distinct recKoRVs with different geographic distributions. All of the identified recombinant viruses appear to have arisen independently and have highly disrupted ORFs, which suggests that recombination with existing degraded endogenous retroelements may be a means by which replication-competent ERVs that enter the germ line are degraded.
AB - Endogenous retroviruses (ERVs) are proviral sequences that result from colonization of the host germ line by exogenous retroviruses. The majority of ERVs represent defective retroviral copies. However, for most ERVs, endogenization occurred millions of years ago, obscuring the stages by which ERVs become defective and the changes in both virus and host important to the process. The koala retrovirus, KoRV, only recently began invading the germ line of the koala (Phascolarctos cinereus), permitting analysis of retroviral endogenization on a prospective basis. Here, we report that recombination with host genomic elements disrupts retroviruses during the earliest stages of germ-line invasion. One type of recombinant, designated recKoRV1, was formed by recombination of KoRV with an older degraded retroelement. Many genomic copies of recKoRV1 were detected across koalas. The prevalence of recKoRV1 was higher in northern than in southern Australian koalas, as is the case for KoRV, with differences in recKoRV1 prevalence, but not KoRV prevalence, between inland and coastal New South Wales. At least 15 additional different recombination events between KoRV and the older endogenous retroelement generated distinct recKoRVs with different geographic distributions. All of the identified recombinant viruses appear to have arisen independently and have highly disrupted ORFs, which suggests that recombination with existing degraded endogenous retroelements may be a means by which replication-competent ERVs that enter the germ line are degraded.
KW - Endogenous retrovirus
KW - Genome evolution
KW - Koala retrovirus
KW - Recombination
KW - Retrovirus
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U2 - 10.1073/pnas.1807598115
DO - 10.1073/pnas.1807598115
M3 - Article
C2 - 30082403
AN - SCOPUS:85051823963
SN - 0027-8424
VL - 115
SP - 8609
EP - 8614
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 34
ER -