Long terminal repeat sequences from virulent and attenuated equine infectious anemia virus demonstrate distinct promoter activities.
In the early 1970s, the Chinese Equine Infectious Anemia Virus (EIAV) vaccine, EIAV(DLA), was developed through successive passages of a wild-type virulent virus (EIAV(L)) in donkeys in vivo and then in donkey macrophages in vitro. EIAV attenuation and cell tropism adaptation are associated with changes in both envelope and long terminal repeat (LTR). However, specific LTR changes during Chinese EIAV attenuation have not been demonstrated. In this study, we compared LTR sequences from both virulent and attenuated EIAV strains and documented the diversities of LTR sequence from in vivo and in vitro infections. We found that EIAV LTRs of virulent strains were homologous, while EIAV vaccine have variable LTRs. Interestingly, experimental inoculation of EIAV(DLA) into a horse resulted in a restriction of the LTR variation. Furthermore, LTRs from EIAV(DLA) showed higher Tat transactivated activity than LTRs from virulent strains. By using chimeric clones of wild-type LTR and vaccine LTR, the main difference of activity was mapped to the changes of R region, rather than U3 region.
Zhou
Tao
T
Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, PR China.
Yuan
Xiu-Fang
XF
Hou
Shao-Hua
SH
Tu
Ya-Bin
YB
Peng
Jin-Mei
JM
Wen
Jian-Xin
JX
Qiu
Hua-Ji
HJ
Wu
Dong-Lai
DL
Chen
Huan-Chun
HC
Wang
Xiao-Jun
XJ
Tong
Guang-Zhi
GZ
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D018397:Equidae; D004859:Equine Infectious Anemia / Q000503:physiopathology / Q000821:virology; D015967:Gene Expression Regulation, Viral; D015756:Genes, tat; D014644:Genetic Variation; D006734:Horse Diseases / Q000503:physiopathology / Q000821:virology; D006736:Horses / Q000821:virology*; D004860:Infectious Anemia Virus, Equine / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D008264:Macrophages / Q000821:virology*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000821:virology*; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D020079:Terminal Repeat Sequences / Q000235:genetics* / Q000502:physiology; D015533:Transcriptional Activation; D014765:Viral Vaccines
D014765:Viral Vaccines