Further clues to the mystery of TT viruses

ETHEL-MICHELE DE VILLIERS; KARIN GUNST; SONJA STEPHAN; SILVIA S. BORKOSKY; CORINNA WHITLEY; IMKE GREWE; HELENE RAHN; ROMANA KIMMEL; SABINE HÄCKER; JIAN-WEI FEI

San Pietro in Bevagna

Workshop; Emerging Oncogenic Viruses; 2012

International Agency for Research on Cancer, World Health Organization

Evidence of the high degree of diversity and complexity of TT viruses is clearly emerging. A few aspects will be addressed and discussed: The highly conserved 70bp region characteristic for primate TTVs, can readily be amplified from bovine serum. Serum samples from pregnant mothers and their matching cord blood samples were analyzed. TTVs and rearranged subviral molecules are being transmitted through the placenta. A number of new TTVs were isolated from these samples. A helper virus function seems to be required for the replication of TTVs. Loss of the mother genome with concomitant formation of defective interfering particles and a µTTV may be seen during the replication of some TT virus types, whereas replication of others result in the persistence of the mother genome with its µTTV only. µTTVs persist in the absence of the mother genome over longer periods of time. Transcription does not mirror the in silico genome organization and in vitro transcription of the large ORF1 (predicted to form the virus capsid protein) results in smaller proteins.