Unodeficient mice tested positive for the virus. Fecal samples from uPA-NOG mice originating from CIEA, Japan but raised in a breeding colony at BSRI tested MuAstV positive. In Japan, cecum samples from laboratory mice from 3 breeders, 4 pharmaceutical companies, 13 order 114311-32-9 research institutes and 30 MedChemExpress CI-1011 universities were screened for MuAstV (Table 2). All three Japanese breeders tested negative in all samples investigated. Mice from two out of four pharmaceutical companies tested positive for MuAstV. Seven out of thirteen research institutes showed positive results in the MuAstV PCR tests, while murine cecum samples from 17 out of 25 of the universities tested positive. Laboratory mice stains testing positive in the US samples were immunodeficient NSG, NOD-SCID, NSG-3GS, C57BL6-Timp32/2, and uPA-NOG mice. Stains positive in Japan were all immunocompetent B6J, ICR, Bash2, BALB/c mice, since immunodeficient mice investigated were from breeders and were all negative. Higher sample size (n.10) was collected for five mouse strains in Japan, namely B6J, BALB/c, ICR, IQI and NOD-SCID (Table 3). MuAstV was detected in 13 , 22 and 16 of the B6J, BALB/c, ICR strains respectively. No Japanese samples from IQI and NOD-SCID mice tested positive. All MuAstV detected by PCR in US and Japanese laboratories were closely related phylogenetically (Fig. 1B and C) with less than 10 nucleotide sequence divergence (Fig.1D). In contrast, MuAstV from laboratory mice is divergent to other MuAstV identified in wild mice [37], with sequence divergence ranging between 26?3 (Fig. 1B 18204824 and C). Mutation sites on the laboratory mice MuAstV RdRP fragment (321 bases) used for the diagnostic PCR were analyzed (Fig. 1D). Synonymous mutations were frequent and, in some cases, common mutations were seen among mice of the same strain in the same facilities (between MuAstV USA/BSRI/NSG/1 and 2; between MuAstV USA/BSRI/NSG/3 and 4; MuAstV USA/ CCHMC/NSG/TF18LM and 19LM) (Fig 1D). Furthermore, mice of the same strains maintained in different facilities contained different MuAstV mutations, for example, NSG mice in BSRI differed from those in CCHMC. Out of the 107 codons RdRP sequence analyzed, 8 (7.5 ) non-synonymous mutation sites were recognized (Fig. 1D). The most common NS mutations were 292Q.R and 347D.N mutations, both of which were found in mice from the US and Japan. The 373H.L mutation only occurred in Japan and the 375E.D mutation only in mice from the US.DiscussionWe identified a murine astrovirus (MuAstV) using a metagenomic approach in pooled tissues from immunodeficient laboratory mice. PCR screening revealed that MuAstV is commonly found in mice facilities in the USA and Japan, including breeding facilities, universities and research institutes. MuAstV was detected in a variety of mouse strains, most consistently in strains with compromised immune systems (NSG, NOD-SCID, NSG-3GS, C57BL6-Timp-32/2 and uPA-NOG), but also in some mouse strains with functional immune systems (B6J, ICR, Bash2, and BALB/c). We also investigated MuAstV infections in facilities that maintain both immunodeficient and immunocompetent mice, including three Japanese breeding facilities and BSRI (Table 1 and 2). The three Japanese breeding facilities were free of MuAstV. At BSRI, MuAstV was detected in all immunocompromised miceMurine Astrovirus 1676428 in Laboratory MiceFigure 1. Genome organization and phylogenetic analyses of the murine astrovirus. A) Genome organization of MuAstV. B) Phylogenetic analysis.Unodeficient mice tested positive for the virus. Fecal samples from uPA-NOG mice originating from CIEA, Japan but raised in a breeding colony at BSRI tested MuAstV positive. In Japan, cecum samples from laboratory mice from 3 breeders, 4 pharmaceutical companies, 13 research institutes and 30 universities were screened for MuAstV (Table 2). All three Japanese breeders tested negative in all samples investigated. Mice from two out of four pharmaceutical companies tested positive for MuAstV. Seven out of thirteen research institutes showed positive results in the MuAstV PCR tests, while murine cecum samples from 17 out of 25 of the universities tested positive. Laboratory mice stains testing positive in the US samples were immunodeficient NSG, NOD-SCID, NSG-3GS, C57BL6-Timp32/2, and uPA-NOG mice. Stains positive in Japan were all immunocompetent B6J, ICR, Bash2, BALB/c mice, since immunodeficient mice investigated were from breeders and were all negative. Higher sample size (n.10) was collected for five mouse strains in Japan, namely B6J, BALB/c, ICR, IQI and NOD-SCID (Table 3). MuAstV was detected in 13 , 22 and 16 of the B6J, BALB/c, ICR strains respectively. No Japanese samples from IQI and NOD-SCID mice tested positive. All MuAstV detected by PCR in US and Japanese laboratories were closely related phylogenetically (Fig. 1B and C) with less than 10 nucleotide sequence divergence (Fig.1D). In contrast, MuAstV from laboratory mice is divergent to other MuAstV identified in wild mice [37], with sequence divergence ranging between 26?3 (Fig. 1B 18204824 and C). Mutation sites on the laboratory mice MuAstV RdRP fragment (321 bases) used for the diagnostic PCR were analyzed (Fig. 1D). Synonymous mutations were frequent and, in some cases, common mutations were seen among mice of the same strain in the same facilities (between MuAstV USA/BSRI/NSG/1 and 2; between MuAstV USA/BSRI/NSG/3 and 4; MuAstV USA/ CCHMC/NSG/TF18LM and 19LM) (Fig 1D). Furthermore, mice of the same strains maintained in different facilities contained different MuAstV mutations, for example, NSG mice in BSRI differed from those in CCHMC. Out of the 107 codons RdRP sequence analyzed, 8 (7.5 ) non-synonymous mutation sites were recognized (Fig. 1D). The most common NS mutations were 292Q.R and 347D.N mutations, both of which were found in mice from the US and Japan. The 373H.L mutation only occurred in Japan and the 375E.D mutation only in mice from the US.DiscussionWe identified a murine astrovirus (MuAstV) using a metagenomic approach in pooled tissues from immunodeficient laboratory mice. PCR screening revealed that MuAstV is commonly found in mice facilities in the USA and Japan, including breeding facilities, universities and research institutes. MuAstV was detected in a variety of mouse strains, most consistently in strains with compromised immune systems (NSG, NOD-SCID, NSG-3GS, C57BL6-Timp-32/2 and uPA-NOG), but also in some mouse strains with functional immune systems (B6J, ICR, Bash2, and BALB/c). We also investigated MuAstV infections in facilities that maintain both immunodeficient and immunocompetent mice, including three Japanese breeding facilities and BSRI (Table 1 and 2). The three Japanese breeding facilities were free of MuAstV. At BSRI, MuAstV was detected in all immunocompromised miceMurine Astrovirus 1676428 in Laboratory MiceFigure 1. Genome organization and phylogenetic analyses of the murine astrovirus. A) Genome organization of MuAstV. B) Phylogenetic analysis.
