Mice transgenic for equine cyclin T1 and ELR1 are susceptible to equine infectious anemia virus infection.
BACKGROUND
As a member of the tumor necrosis factor receptor (TNFR) protein superfamily, equine lentivirus receptor 1 (ELR1) has been shown to be expressed in various equine cells that are permissive for equine infectious anemia virus (EIAV) replication. The EIAV Tat protein (eTat) activates transcription initiated at the viral long terminal repeat (LTR) promoter through a unique mechanism that requires the recruitment of the equine cyclin T1 (eCT1) cofactor into the viral TAR RNA target element. In vitro studies have demonstrated that mouse fibroblast cell lines (e.g., NIH 3T3 cells) that express the EIAV receptor ELR1 and eCT1 support the productive replication of EIAV. Therefore, we constructed transgenic eCT1- and ELR1-expressing mice to examine whether they support in vivo EIAV replication.


RESULTS
For the first time, we constructed mice transgenic for ELR1 and eCT1. Real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis confirmed that ELR1 and eCT1 were expressed in the transgenic mouse tissues, particularly in the intestines, spleen and lymph nodes. Consistent with the results of EIAV infection in NIH 3T3 cells expressing ELR1 and eCT1, mouse embryonic fibroblasts (MEFs) from the transgenic mice could support EIAV replication. More importantly, this virus could infect and replicate in mouse blood monocyte-derived macrophages (mMDMs). Macrophages are the principle target cell of EIAV in its natural hosts. Furthermore, after the transgenic mice were inoculated with EIAV, the virus could be detected not only in the plasma of the circulating blood but also in multiple organs, among which, the spleen and lymph nodes were the predominant sites of EIAV replication. Finally, we found that consistent with high viral replication levels, the relevant pathological changes occurred in the spleen and lymph nodes.


CONCLUSIONS
Our results show that mice transgenic for ELR1 and eCT1 are susceptible to EIAV infection and replication. Further, EIAV infection can cause lesions on the spleen and lymph nodes, similar to those frequently observed in horses, the natural hosts. Therefore, ELR1 and eCT1 are essential in vivo for EIAV invasion and replication.
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. chengdu1981@163.com.|Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150001, China. chengdu1981@163.com.
Cheng
C
Du
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. jma@hvri.ac.cn.
Jian
J
Ma
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. liuqiang_yyy@163.com.
Qiang
Q
Liu
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. liyunfei@nibs.ac.cn.
Yun-Fei
YF
Li
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. hexijun@caas.cn.
Xi-Jun
XJ
He
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. sndhr@163.com.
Yue-Zhi
YZ
Lin
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. xuefengwang1982@126.com.
Xue-Feng
XF
Wang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. mqw@hvri.ac.cn.
Qing-Wen
QW
Meng
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. xjw@hvri.ac.cn.
Xiaojun
X
Wang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. jianhua_uc@126.com.
Jian-Hua
JH
Zhou
D000825:Animal Structures / Q000821:virology; D000818:Animals; D015153:Blotting, Western; D056906:Cyclin T / Q000096:biosynthesis* / Q000235:genetics; D004195:Disease Models, Animal; D004859:Equine Infectious Anemia / Q000473:pathology / Q000821:virology*; D015870:Gene Expression; D020869:Gene Expression Profiling; D006736:Horses; D004860:Infectious Anemia Virus, Equine / Q000254:growth & development*; D008198:Lymph Nodes / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D060888:Real-Time Polymerase Chain Reaction; D011991:Receptors, Virus / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000473:pathology; D014779:Virus Replication
D056906:Cyclin T; D011991:Receptors, Virus; D011994:Recombinant Proteins