Genomic characterization of TT viruses (TTVs) in pigs, cats and dogs and their relatedness with species-specific TTVs in primates and tupaias

Abstract

Using PCR with primers derived from a non-coding region of the human TT virus (TTV) genome, the TTV sequence in serum samples obtained from pigs (Sus domesticus), dogs (Canis familiaris) and cats (Felis catus) was identified and the entire genomic sequence was determined for each representative isolate. Three TTV isolates (Sd-TTV31 from a pig, Cf-TTV10 from a dog and Fc-TTV4 from a cat) comprising 2878, 2797 and 2064 nucleotides, respectively, each had three open reading frames (ORFs) encoding 436-635 (ORF1), 73-105 (ORF2) and 224-243 (ORF3) aa but lacked ORF4, similar to tupaia TTV. ORF3 was presumed to arise from a splicing of TTV mRNA, similar to human prototype TTV. Although the nucleotide sequence of Sd-TTV31, Cf-TTV10 and Fc-TTV4 differed by more than 50 % from each other and from previously reported TTVs of 3n4-3n9 kb and TTV-like mini viruses (TLMVs) of 2n8-3n0 kb isolated from humans and non-human primates as well as tupaia TTVs of 2n2 kb, they resembled known TTVs and TLMVs with regard to genomic organization and presumed transcriptional profile rather than animal circoviruses of 1n7-2n3 kb. Phylogenetic analysis revealed that Sd-TTV31, Cf-TTV10 and Fc-TTV4 were closer to TTVs from lower-order primates and tupaias than to TTVs from higher-order primates and TLMVs. These results indicate that domestic pigs, cats and dogs are naturally infected with species-specific TTVs with small genomic size and suggest a wide distribution of TTVs with extremely divergent genomic sequence and length in animals.

Expression profile and subcellular localization of Torque teno sus virus proteins

“…TTSuVs have similar genomic organization with human-infecting TTVs but share less than 45 % nt sequence identity (Niel et al, 2005;Okamoto et al, 2002). Recent studies also demonstrated a high degree of genetic variability between TTSuV1 and TTSuV2 (Cortey et al, 2011).…”

“…Discrepancies observed between studies suggest that the genomic diversity found in TTV isolates can be associated with different strategies of expression and localization of viral proteins (Müller et al, 2008). It has been suggested that the transcriptional profile of TTSuV would be similar to that found in human TTVs (Okamoto et al, 2002), but experimental evidence is still lacking.…”

Quantitative Detection of Porcine Torque Teno Virus in Porcine Circovirus-2–Negative and Porcine Circovirus–Associated Disease-Affected Pigs

“…Even though TTV could infect several species, including human, horse, dog, cat, and pig, TTV has shown host specificity and variable genomic length within the order of the animal. 17,20 The genomic length of TTV in humans and primates is approximately 3.8 kb in length and is approximately 2.9 kb in pigs and dogs. Swine TTV has also shown worldwide distribution, and a high seropositive ratio in the general pig population has been reported.…”

Torque teno sus virus (TTSuV) infection at different stages of pig production cycle

“…This virus was first isolated from a Japanese man with non A-E post-transfusional hepatitis (Nishizawa et al 1997). Since then, TTV has been shown to infect humans, non-human primates, and farm animals (Leary et al 1999, Okamoto et al 2000, 2001, 2002, Brassard et al 2008.…”

“…The first full genome analysis of TTSuV was completed by Okamoto et al (2002), and the differentiation of TTSuV into separate species was performed by Niel et al (2005). TTSuV belongs to the family Anelloviridae and is classified into the species TTSuV1a (represented by Sd-TTV31 strain) and TTSuV1b (represented by Sd-TTV1p strain) in the genus Iotatorquevirus, and TTSuVk2 (represented by Sd-TTV2p strain) in the genus Kappatorquevirus (ICTV 2012).…”