MuERVC: a new family of murine retrovirus-related repetitive sequences and its relationship to previously known families

Abstract

Characterization of a new murine endogenous retrovirus-related sequence named MuERVC-C105 is reported. This sequence was found to be most similar to the murine leukemia C-type retroviruses and to murine defective endogenous retrovirus-like families MuRRS and MuRVY, although MuERVC-C105 has a novel LTR. MuERVC-C105, like MuRRS and MuRVY, represents a family of retrovirus-like sequences characterized by many defects in its reading frames. Phylogenetic analyses, in particular analysis of nonsynonymous and synonymous nucleotide substitutions in the descent of these sequences, revealed that the MuERVC-C105, MuRRS, and MuRVY families were each derived from a different nondefective retroviral ancestor, thus justifying the new family name MuERVC. These nondefective ancestors cluster together with Gibbon Ape Leukemia Virus, but were nearly as distinct from each other as are other subgroups of murine leukemia virus (MoMLV, BaEV, GALV). The analysis further indicated that, in spite of the high density of defects in these three families, most of their divergence from their common ancestor was as nondefective retroviruses.

Endogenous retroviruses

“…In addition to these mutated proviral genomes, there are at least 500 copies of solo LTRs, probably arising through homologous recombination between the two LTRs. Two additional families (MuRV-Y and MuERV-C) are closely related, but are predicted to have been seeded by a separate ‘founder’ retrovirus [68]. Similar to MuRRS, MuERV-C family members are highly mutated but with detectable gag , pol , and env genes, the latter being often extensively deleted.…”

Syncytin-A and syncytin-B, two fusogenic placenta-specific murine envelope genes of retroviral origin conserved in Muridae

“…In mice, eight families of ERVs, with a structure close to the integrated proviral form of exogenous retroviruses (gag-, pol-, and env-related regions bordered by two LTRs), have been described. Those with close exogenous relatives include type B proviruses related to the murine mammary tumor virus (6) and type C proviruses related to the Moloney murine leukemia virus (MLV), with the endogenous MLV, MuRRS, MuRVY, GLN, MuERVC, and MmERV family members (1,7,8). A family of sequences with no exogenous relatives, called IAPE (intracisternal A-particle sequences with an envelope gene), was also described (9).…”

Phylogeny-Directed Search for Murine Leukemia Virus-Like Retroviruses in Vertebrate Genomes and in Patients Suffering from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Prostate Cancer

“…MuRRS [18] and MuERVC [19] sequences were ancestral to groups G1 and G2 at the level of 64% similarity to their consensuses. …”

“…GLN MuERV is from Ribet et al [15]. Symbols: ∗ position of XMRV/HMRV, § recombinant MuERV Sp496-5Sb [16] from Mus spretus, ¤ hortulanus endogenous murine virus, HEMV, from Mus spicilegus [17], # MuRRS [18], and MuERVC [19]. An ERV-S sequence [20] was used to root the tree.…”