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Complete Genome Sequences of New Xenotropic Murine Leukemia Viruses

Jemal

Senior Member
Messages
1,031
I found this article pretty interesting:
Complete Genome Sequences of New Xenotropic Murine Leukemia Viruses from the Senescence-Accelerated Mouse (SAM): Molecular and Phylogenetic Analyses

Citation: Lee Y-J, Jeong B-H, Choi E-K, Carp RI, Kim Y-S (2013) Complete Genome Sequences of New Xenotropic Murine Leukemia Viruses from the Senescence-Accelerated Mouse (SAM): Molecular and Phylogenetic Analyses. PLoS ONE 8(2): e55669. doi:10.1371/journal.pone.0055669

Editor: Man-Seong Park, College of Medicine, Hallym University, Republic of Korea

Received: September 14, 2012; Accepted: December 28, 2012; Published: February 5, 2013

Approximately 10% of the mouse genome is constituted by endogenous retroviruses (ERVs), and a number of mouse ERVs remain active. Many copies of endogenous murine leukemia viruses (MuLVs) are detected in the genomes of inbred mouse strains. Some of these MuLVs are transcriptionally active or produce infectious virus particles. Previously, we identified partial env sequences of new xenotropic MuLVs (X-MuLVs) from a senescence-accelerated mouse (SAM) strain. In the present study, we investigated and characterized the complete sequences of the X-MuLVs. The complete genomes and open reading frames (ORFs) of two X-MuLVs, designated xmlv15 and xmlv18 (accession nos. HQ154630 and HQ154631, respectively), were molecularly cloned from the genome of the SAM mice. We confirmed that the xmlv15 and xmlv18 sequences are distinct from all known MuLV genomes and are most similar to DG-75 MuLV. Moreover, we found that common strains of laboratory mice carry our newly identified xmlvs. Additionally, the expression levels of xmlv15-related sequences were much higher in C57BL and ICR mice than in the SAM strains without any stimulators. Our findings suggest that a specific group of endogenous MuLVs is constitutively expressed in the brain and that they may participate in normal functions and/or pathogenic conditions.

Also from the article:

Horizontal transmission of MuLVs in mice has been reported [34], and mice and rats distributed worldwide can carry disease-causing agents that can infect humans and livestock [35]. Furthermore, previously published studies reported that new XMRVs are detected in humans [36]–[38], and that XPR1 is required for XMRV infection [39]. Overexpression of xmlv15-related sequences might represent a risk for laboratory workers who perform research on animals. In this regard, the investigation of endogenous X-MuLVs in individuals who usually handle laboratory mouse strains is important. We performed assays to detect xmlvs-related sequences using specific primers in the peripheral blood from 20 laboratory workers at the DNA and RNA levels. Fortunately, none of workers was positive for the newly identified xmlvs (data not shown). The transcriptionally active X-MuLVs may also influence the results of experimental infections of inbred mice with disease causing agents, such as viruses and peptides. Indeed, the levels of the X-MuLV expression in addition to the types of E- and P-MuLV were found to be increased in the brains of scrapie-infected SAM stains, which might affect the progression of scrapie pathogenesis in the SAM mice [40]. The association of the etiological agent of XMRV with human diseases is a highly controversial topic because convincing evidence demonstrating the possibility of contamination of mouse DNA in XMRV-positive samples have been reported [41]. Even if XMRV or related gammaretroviruses have not yet infected in humans, the risk of such infections occurring remains because X-MuLV receptor, Xpr1, is widely expressed in human tissue [42]. Since xmlvs have different transcriptional activity, more examinations will be needed to find the comprise characters of each xmlv. Therefore, we are planning to make construct of xmlvs for transfection study and to screen of xmlvs and xmlvs-related sequences activity before and after treatment of immune triggers in the organs of various mice including AKR mice.

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055669?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed: plosone/PLoSONE (PLoS ONE Alerts: New Articles)
 

lansbergen

Senior Member
Messages
2,512
Indeed, the levels of the X-MuLV expression in addition to the types of E- and P-MuLV were found to be increased in the brains of scrapie-infected SAM stains, which might affect the progression of scrapie pathogenesis in the SAM mice