Characterization of an integrated, endogenous mouse mammary tumor virus-like (MMTV) betaretrovirus genome in a black Syrian hamster (Mesocricetus auratus)

Abstract

Retroviruses (family Retroviridae) are important agents of humans and animals. This study reports the detection and complete genome characterization of a novel endogenous retrovirus from the black Syrian hamster (Mesocricetus auratus) with a squamous cell skin tumor. The proviral genome, tentatively named black Syrian hamster retrovirus (BSHRV/2013/HUN, MK304634), was 8784 nucleotide in length with typical full-length betaretrovirus genome organization of 5'LTR-gag-pro-pol-env-3'LTR and with a characteristic mouse mammary tumor virus-like (MMTV) betaretrovirus dUTPase domain but without a sag gene. The BSHRV gag (534aa), pro/ pol (~1099aa) and env (672aa) proteins had 56%/63%/50% aa identity to the corresponding proteins of MMTV (AF228552). The proviral DNA is detectable in tumor as well as in tumor-free cells by conventional PCR and qPCR but only visible in the tumor cells by in situ hybridization. Low level retroviral RNA expression was found only in the DNase-treated RNA tumor samples using RT/nested PCR. BSHRV/2013/HUN-like betaretrovirus DNA was also identified from a faecal and tissue samples from 1 of the further 3 tested individuals by nested-PCR and qPCR. Further research is needed to investigate the distribution, activity and etiological role of this novel MMTV-like betaretrovirus species in hamster.

Common Spontaneous Tumors and Tumor-like Lesions in 70 Pet Rodents and Negative MMTV Detection in Mammary Tumors

“…In the exogenous route, mice receive viruses from milk through dendritic cells and lymphocytes in the gastrointestinal system. In addition to mice, other rodents, including buffalo rats and hamsters, are infected with MMTV [7][8][9]. Moreover, MMTV env gene-like sequences are found in human breast cancers, implying a potential zoonotic risk between humans and pet rodents [10,11].…”

Detection and Characterisation of an Endogenous Betaretrovirus in Australian Wild Deer

“…In contrast to classes I and III, the class II ERVs have a more restricted host range, comprised mainly of mammals and birds; however, they have also recently been detected in amphibians [6][7][8]. Among class II ERVs, full-length endogenous betaretroviruses have been detected in the genomes of livestock [9][10][11][12], rodents [9,13], primates [9,14,15], bats [16,17], and the common brushtail possum (Trichosurus vulpecula) [18]. Betaretrovirus-related elements have been previously detected in wild cervid genomes such as caribou (Rangifer tarandus) and white-tailed deer (Odocoileus virginianus) utilising PCR assays targeting conserved regions of the retroviral pro and/or pol genes; however, these elements still remain uncharacterised [6].…”