Expression patterns of endogenous avian retrovirus ALVE1 and its response to infection with exogenous avian tumour viruses.
Endogenous retroviruses (ERVs) are genomic elements that are present in a wide range of vertebrates and have been implicated in a variety of human diseases, including cancer. However, the characteristic expression patterns of ERVs, particularly in virus-induced tumours, is not fully clear. DNA methylation was analysed by bisulfite pyrosequencing, and gene expression was analysed by RT-qPCR. In this study, we first found that the endogenous avian retrovirus ALVE1 was highly expressed in some chicken tissues (including the heart, bursa, thymus, and spleen) at 2 days of age, but its expression was markedly decreased at 35 days of age. In contrast, the CpG methylation level of ALVE1 was significantly lower in heart and bursa at 2 days than at 35 days of age. Moreover, we found that the expression of ALVE1 was significantly inhibited in chicken embryo fibroblast cells (CEFs) and MSB1 cells infected with avian leukosis virus subgroup J (ALVJ) and reticuloendotheliosis virus (REV) at the early stages of infection. In contrast, the expression of the ALVE1 env gene was significantly induced in CEFs and MSB1 cells infected with Marek's disease virus (MDV). However, the methylation and expression levels of the ALVE1 long terminal repeat (LTR) did not show obvious alterations in response to viral infection. The present study revealed the expression patterns of ALVE1 in a variety of chicken organs and tissues and in chicken cells in response to avian tumour virus infection. These findings may be of significance for understanding the role and function of ERVs that are present in the host genome.
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Xuming
X
Hu
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Wenqi
W
Zhu
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Shihao
S
Chen
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Yangyang
Y
Liu
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Zhen
Z
Sun
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Tuoyu
T
Geng
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Chengyi
C
Song
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Bo
B
Gao
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.
Xiaoyan
X
Wang
Ministry of Education Key Lab for Avian Preventive Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China.
Aijian
A
Qin
Institute of Epigenetics and Epigenomics and College of Animal Science and Technology, Yangzhou University, No. 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China. hmcui@yzu.edu.cn.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China. hmcui@yzu.edu.cn.|Institute of Comparative Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China. hmcui@yzu.edu.cn.
Hengmi
H
Cui
D000825:Animal Structures / Q000821:virology; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D060085:Coinfection / Q000662:veterinary* / Q000821:virology; D019175:DNA Methylation; D020077:Endogenous Retroviruses / Q000235:genetics* / Q000254:growth & development; D005347:Fibroblasts / Q000821:virology; D020869:Gene Expression Profiling; D015967:Gene Expression Regulation, Viral; D056265:Microbial Interactions; D009858:Oncogenic Viruses / Q000235:genetics* / Q000254:growth & development; D060888:Real-Time Polymerase Chain Reaction; D012192:Retroviridae Infections / Q000150:complications* / Q000821:virology; D017422:Sequence Analysis, DNA; D014412:Tumor Virus Infections / Q000662:veterinary* / Q000821:virology