Endogenous Primate and Feline Type C Viruses

Todaro, George J.; Benveniste, R E; Callahan, Robert; Lieber, Michael M.; Sherr, Charles J.

doi:10.1101/sqb.1974.039.01.133

Cited by 58 publications

(33 citation statements)

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“…Solution hybridization experiments with. baboon endogenous virus (BaEV) cDNA probes have demonstrated the existence of multiple copies of reactive type C proviruses in the chromosomal DNAs of the baboon and related simian species (16,17). Although sequences hybridizing to labeled BaEV RNA have been reported in some human leukemic cellular DNAs (18), no endogenous type C. retroviral DNA has been detected in preparations of.normal human DNA (13,15,17) despite the use ofnonstringent reaction conditions (19) or the sensitive blothybridization technique (20).…”

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confidence: 99%

Identification and cloning of endogenous retroviral sequences present in human DNA.

Martin¹,

Bryan²,

Rasheed³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

193

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Using nonstringent annealing conditions and a 2.75-kilobase segment of cloned African green monkey DNA that specifically hybridizes to the proviruses of AKR'ecotropic murine leukemia virus (MuLV) and baboon endogenous virus (BaEV) as a probe, we detected related sequences in three different preparations of human brain DNA fragments. The blot-hybridization pattern obtained with cleaved human DNA was similar to that previously reported for the interaction of MuLV cDNA and cleaved mouse DNA and suggested the presence ofnumerous copies of retrovirus-related sequences in the human genome. The labeled 2.75-kilobase fragment derived from cloned monkey DNA was used to screen a human DNA library in Charon 4A. One clone obtained hybridized to three contiguous MuLV-and BaEV-reactive fragments of the cloned monkey DNA and to multiple fragments of human DNA including a prominent 1.0-kilobase EcoRI fragment also present in the clone.In the mouse, certain endogenous type C proviruses have been shown to be vertically transmitted (1-3), have been mapped to specific chromosomal loci (4-6), and have the potential ofbeing expressed as infectious ecotropic and xenotropic (7) murine leukemia viruses (MuLV). Comparison ofresults from nucleic acid hybridization experiments, which indicate the existence of numerous copies of endogenous mouse proviruses (8-10), with those derived from genetic andvirus isolation studies, which point to a few defined inducible loci in the genomes of certain inbred mouse strains (4-6, 11), strongly suggests that the majority of the MuLV-reactive sequences in mouse DNA consist ofincomplete viral DNA segments whose function is unknown.Type C endogenous retroviruses have also been recovered from several different Old World monkeys including the baboon (12), stump-tail macaque (13), rhesus (14), and colobus (15 We recently. reported the molecular cloning of a 17-kilobase (kb) segment from African green monkey (AGM) DNA which had nearly 5 kb of homology with AKR ecotropic MuLV DNA (21). In the present manuscript we show that the internal organization of the endogenous type C AGM and baboon provi:-ruses, including 8 of 10 restriction enzyme cleavage sites, hasbeen highly conserved. Furthermore, by using a radiolabeled. 2.75-kb BamHI fragment ofthe cloned ACM-DNA, which specifically hybridizes to a similarly sized BamHI fragment (22) of the BaEV provirus, hybridization to several bands in three different restricted preparations of human DNA was observed. Based on our ability to detect type C virus-related sequences in human DNA, we cloned an 11-kb segment from human DNA which hybridizes to AGM and mouse proviral DNAs.MATERIALS AND METHODS Preparation and Cleavage ofCellular DNA. High molecular weight AGM and rhesus monkey liver DNAs were purified from fresh tissue as described (23). Baboon cellular-DNA was prepared from a cell line (CP 21) established from primary skin fibroblasts. DNA was isolated from three human brain specimens as outlined (24). Cellular DNAs were digested with restriction enzymes, ele...

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confidence: 99%

Identification and cloning of endogenous retroviral sequences present in human DNA.

Martin¹,

Bryan²,

Rasheed³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

193

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“…The genetic information of endogenous C-type viruses is present in all somatic and germ cells of all individuals of many species, and these virus-related genes are transmitted genetically according to Mendelian expectations (1)(2)(3)(4)(5). In contrast, exogenously infecting C-type viruses are not transmitted genetically and thus are not part of the normal genetic complement of an animal (6,7).…”

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confidence: 99%

“…Whereas it is reasonable to assume that exogenous viruses evolved from endogenous viruses (7)(8)(9), the converse event, namely the conversion of exogenous viruses into endogenous viruses, seems to be very rare. However, recent evidence suggests that the transfer of an exogenous virus into the germ line of another species can occur during evolution (1,10).…”

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confidence: 99%

Germ line integration and Mendelian transmission of the exogenous Moloney leukemia virus.

Jaenisch¹

1976

Proc. Natl. Acad. Sci. U.S.A.

426

181

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Mice were infected with the exogenous Moloney leukemia virus (M-MuLV) at two different stages of development. Either newborn mice (which can be considered as essentially fully differentiated animals) or preimplantation mouse embryos (at the 4-8 cell stage) were infected with M-MuLV. In both cases, animals that had developed an MMuLV-induced leukemia were obtained. Two lines of evidence indicate that infection of preimplantation embryos, in contrast to infection of newborns, can lead to integration of the virus into the germ line.1. Viremic males of the first backcross generation (N-i generation) transmitted the virus to 50% of their offspring (N-2 generation) when mated with uninfected females. Likewise, a 50% transmission was observed from viremic N-2 and N-3 males to the next generations.2. Molecular hybridization experiments revealed that viremic N-1 and N-2 animals carried one copy of M-MuLV per diploid mouse genome equivalent in all "non-target" organs tested.Together, both experiments indicate that the exogenous M-MuLV can be converted to an endogenous virus after infection of preimplantation embryos. The available evidence suggests that M-MuLV integrated into the germ line at one out of two possible integration sites. Thus, viremic backcross animals are heterozygous for a single Mendelian locus carrying the M-MuL V gene. During leukemogenesis an amplification of the M-MuLV from one copy to a maximum of four copies per diploid mouse genome equivalent takes place in, the tumor tissues.The genetic information of endogenous C-type viruses is present in all somatic and germ cells of all individuals of many species, and these virus-related genes are transmitted genetically according to Mendelian expectations (1-5). In contrast, exogenously infecting C-type viruses are not transmitted genetically and thus are not part of the normal genetic complement of an animal (6, 7). Whereas it is reasonable to assume that exogenous viruses evolved from endogenous viruses (7-9), the converse event, namely the conversion of exogenous viruses into endogenous viruses, seems to be very rare. However, recent evidence suggests that the transfer of an exogenous virus into the germ line of another species can occur during evolution (1, 10).Prior to this study, the conversion of an exogenous into an endogenous virus had not been observed under defined laboratory conditions. Thus, leukemic mice infected in utero or after birth with leukemia virus never transmitted the virus genetically, i.e., from the leukemic father to the offspring (11,12). In this instance, it is important to distinguish genetic transmission from the congenital transmission (13) which occurs from leukemic mothers to the majority of their offspring by infection through the placenta or the milk. The apparent resistance of the germ line to virus infection may be explained by the "organtropism" of murine leukemia viruses, i.e., the observation that only certain "target" tissues, such as spleen or thymus cells, are susceptible to infection with leukemia viruses,...

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“…Whereas exogenous FeLVs are transmitted horizontally, endogenous feline leukemia proviruses are part of the germ line and are transmitted from parent to offspring as integral components of chromosomes (5,20). Endogenous FeLVs are found in wild species of the genus Felis closely related to the domestic cat, although they are not present in species from other lineages within the Felidae (4,(56)(57)(58). Thus, enFeLVs are believed to have entered the germ line after the initial radiation of lineages in the cat family but before the radiation of domestic cat lineage species (3,23,25), although subsequent additional integrations into the germ line may also have occurred (50).…”

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confidence: 99%

Insertional Polymorphisms of Endogenous Feline Leukemia Viruses

Roca

Nash

Menninger

et al. 2005

J Virol

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The number, chromosomal distribution, and insertional polymorphisms of endogenous feline leukemia viruses (enFeLVs) were determined in four domestic cats (Burmese, Egyptian Mau, Persian, and nonbreed) using fluorescent in situ hybridization and radiation hybrid mapping. Twenty-nine distinct enFeLV loci were detected across 12 of the 18 autosomes. Each cat carried enFeLV at only 9 to 16 of the loci, and many loci were heterozygous for presence of the provirus. Thus, an average of 19 autosomal copies of enFeLV were present per cat diploid genome. Only five of the autosomal enFeLV sites were present in all four cats, and at only one autosomal locus, B4q15, was enFeLV present in both homologues of all four cats. A single enFeLV occurred in the X chromosome of the Burmese cat, while three to five enFeLV proviruses occurred in each Y chromosome. The X chromosome and nine autosomal enFeLV loci were telomeric, suggesting that ectopic recombination between nonhomologous subtelomeres may contribute to enFeLV distribution. Since endogenous FeLVs may affect the infectiousness or pathogenicity of exogenous FeLVs, genomic variation in enFeLVs represents a candidate for genetic influences on FeLV leukemogenesis in cats.Endogenous feline leukemia virus (enFeLV) sequences are present in the genome of the domestic cat, Felis catus. They are homologous to exogenous feline leukemia viruses, which are oncogenic retroviruses capable of inducing both proliferative and degenerative diseases (15, 34). Whereas exogenous FeLVs are transmitted horizontally, endogenous feline leukemia proviruses are part of the germ line and are transmitted from parent to offspring as integral components of chromosomes (5,20). Endogenous FeLVs are found in wild species of the genus Felis closely related to the domestic cat, although they are not present in species from other lineages within the Felidae (4, 56-58). Thus, enFeLVs are believed to have entered the germ line after the initial radiation of lineages in the cat family but before the radiation of domestic cat lineage species (3,23,25), although subsequent additional integrations into the germ line may also have occurred (50).Endogenous FeLV sequences do not by themselves produce infectious virus but readily recombine with exogenous feline leukemia viruses, notably in the env region that codes for the viral coat, producing recombinant viruses with altered biological activity and pathogenicity (4,17,21,43,44,51,53,54,60). For example, the recombinant subgroup C viruses have been found to induce aplastic anemia (18). Furthermore, portions of the enFeLV env region are transcribed and translated in lymphoma and other cell lines (26), producing a truncated envelope protein that inhibits infection by exogenous subgroup B feline leukemia viruses (26). Transcription and translation of enFeLVs have also been demonstrated in tissues from healthy cats, including lymphoid tissue, suggesting a protective role for enFeLVs in vivo (7, 26). Likewise, inoculation with recombinant subgroup B exogenous FeLV attenuates ...

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Endogenous Primate and Feline Type C Viruses

Cited by 58 publications

References 0 publications

Identification and cloning of endogenous retroviral sequences present in human DNA.

Identification and cloning of endogenous retroviral sequences present in human DNA.

Germ line integration and Mendelian transmission of the exogenous Moloney leukemia virus.

Insertional Polymorphisms of Endogenous Feline Leukemia Viruses

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