Analysis of the entire genomes of fifteen torque teno midi virus variants classifiable into a third group of genus Anellovirus.
ABSTRACT Recently, we identified a novel human virus with a circular DNA genome of 3.2 kb, tentatively designated as torque teno midi virus (TTMDV), with a genomic organization resembling those of torque teno virus (TTV) of 3.8-3.9 kb and torque teno mini virus (TTMV) of 2.8-2.9 kb. To investigate the extent of genomic variability of TTMDV genomes, the full-length sequence was determined for 15 TTMDV isolates obtained from viremic individuals in Japan. The 15 TTMDV isolates comprised 3175-3230 bases and shared 67.0-90.3% identities with each other, and were only 68.4-73.0% identical to the 3 reported TTMDV isolates over the entire genome. TTMDV possessed a genomic organization with four open reading frames (ORF1-ORF4) with characteristic sequence motifs and stem and loop structures with high GC content, similar to TTV and TTMV. The total of 18 TTMDV genomes differed by up to 60.7% from each other in the amino acid sequence of ORF1 (658-677 amino acids), but segregated phylogenetically into the same cluster, which was distantly related to the TTVs and TTMVs. These results indicate that TTMDV with a circular DNA genome of 3.2 kb, has an extremely high degree of genomic variability, and is classifiable into a third group in the genus Anellovirus.
- SourceAvailable from: Tytti Vuorinen
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- "TTV is very often detected in blood; the prevalence of TTV DNA in the blood of healthy individuals is approximately 70-90% . A single TTV infection may persist for years and cause chronic viremia   . Simultaneous infections by different TTV variants may also occur. "
ABSTRACT: The diagnostics of respiratory viral infections has improved markedly during the last 15 years with the development of PCR techniques. Since 1997, several new respiratory viruses and their subgroups have been discovered: influenza A viruses H5N1 and H1N1, human metapneumovirus, coronaviruses SARS, NL63 and HKU1, human bocavirus, human rhinoviruses C and D and potential respiratory pathogens, the KI and WU polyomaviruses and the torque teno virus. The detection of previously known viruses has also improved. Currently, a viral cause of respiratory illness is almost exclusively identifiable in children, but in the elderly, the detection rates of a viral etiology are below 40%, and this holds also true for exacerbations of chronic respiratory illnesses. The new viruses cause respiratory symptoms like the common cold, cough, bronchitis, bronchiolitis, exacerbations of asthma and chronic obstructive pulmonary disease and pneumonia. Acute respiratory failure may occur. These viruses are distributed throughout the globe and affect people of all ages. Data regarding these viruses and the elderly are scarce. This review introduces these new viruses and reviews their clinical significance, especially with regard to the elderly population.The Open Respiratory Medicine Journal 07/2011; 5:61-9. DOI:10.2174/1874306401105010061
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- "ORF2 encodes 111 amino acids and shares no amino acid sequence identity with proteins in GenBank. ORF2 lacks the motif W-X 7 -H-X 3 -C- X 1 -C-X 5 -H that is conserved among TTVs, TTMVs and TTMDVs (Hijikata et al., 1999; Ninomiya et al., 2007, 2009; Okamoto et al., 2000; Takahashi et al., 2000). ORF3 encodes 204 amino acids, and shares weak amino acid sequence identity (16 %) with ZcAV ORF3 only, indicating that SealAV could be more closely related to ZcAV than to Fig. 1. "
ABSTRACT: To investigate viral pathogens potentially involved in a mortality event of 21 Pacific harbor seals (Phoca vitulina richardsii) in California in 2000, viral metagenomics was performed directly on lung samples from five individuals. Metagenomics revealed a novel seal anellovirus (SealAV), which clusters phylogenetically with anelloviruses from California sea lions and domestic cats. Using specific PCR, SealAV was identified in lung tissue from two of five animals involved in the 2000 mortality event, as well as one of 20 harbor seal samples examined post-mortem in 2008. The identification of SealAV in multiple years demonstrates that this virus is persistent in the harbor seal population. SealAV is the second anellovirus reported in the lungs of pinnipeds, suggesting that anellovirus infections may be common amongst marine mammals and that more research is needed to understand the roles of these viruses in marine mammal health and disease.Journal of General Virology 03/2011; 92(Pt 6):1318-23. DOI:10.1099/vir.0.029678-0 · 3.53 Impact Factor
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- "In the case of TTMV, full-length genomic sequences of 17 isolates have been determined thus far, and four highly divergent genetic groups have been proposed (Biagini et al., 2001b, 2007; Okamoto et al., 2000b; Takahashi et al., 2000). Upon analysing more TTMDV sequences, we noticed that they formed a large swarm of isolates differing in length (3175–3230 nt) and in sequence (33 % divergence over the entire genomic sequence) (Ninomiya et al., 2007b). Our previous study using a newly developed PCR method revealed high frequencies of viraemia with TTV (99.2 %), TTMDV (82.4 %) and TTMV (89.7 %) among apparently healthy subjects of 1–81 years of age. "
ABSTRACT: Humans are frequently infected with three anelloviruses which have circular DNA genomes of 3.6-3.9 kb [Torque teno virus (TTV)], 2.8-2.9 kb [Torque teno mini virus (TTMV)] and 3.2 kb [a recently discovered anellovirus named Torque teno midi virus (TTMDV)]. Unexpectedly, human TTMDV DNA was not detectable in any of 74 chimpanzees tested, although all but one tested positive for both human TTV and TTMV DNA. Using universal primers for anelloviruses, novel variants of TTMDV that are phylogenetically clearly separate from human TTMDV were identified from chimpanzees, and over the entire genome, three chimpanzee TTMDV variants differed by 17.9-20.3 % from each other and by 40.4-43.6 % from all 18 reported human TTMDVs. A newly developed PCR assay that uses chimpanzee TTMDV-specific primers revealed the high prevalence of chimpanzee TTMDV in chimpanzees (63/74, 85 %) but low prevalence in humans (1/100). While variants of TTV and TTMV from chimpanzees and humans were phylogenetically interspersed, those of TTMDV were monophyletic for each species, with sequence diversity of <33 and <20 % within the 18 human and three chimpanzee TTMDV variants, respectively. Maximum within-group divergence values for TTV and TTMV were 51 and 57 %, respectively; both of these values were substantially greater than the maximum divergence among TTMDV variants (44 %), consistent with a later evolutionary emergence of TTMDV. However, substantiation of this hypothesis will require further analysis of genetic diversity using an expanded dataset of TTMDV variants in humans and chimpanzees. Similarly, the underlying mechanism of observed infrequent cross-species infection of TTMDV between humans and chimpanzees deserves further analysis.Journal of General Virology 02/2009; 90(Pt 2):347-58. DOI:10.1099/vir.0.007385-0 · 3.53 Impact Factor