title: DNA methylation and regulation of the CD8A after duck hepatitis virus type 1 infection.
abstract: BACKGROUND
  Cluster of differentiation 8 (CD8) is expressed in cytotoxic T cells, where it functions as a co-receptor for the T-cell receptor by binding to major histocompatibility complex class I (MHCI) proteins, which present peptides on the cell surface. CD8A is critical for cell-mediated immune defense and T-cell development. CD8A transcription is controlled by several cis-acting elements and trans-acting elements and is also regulated by DNA methylation. However, the epigenetic regulation of CD8A in the duck and its relationship with virus infection are still unclear.
  
  
  RESULTS
  We investigated the epigenetic transcriptional regulatory mechanisms, such as DNA methylation, for the expression of the CD8A and further evaluated the contribution of such epigenetic regulatory mechanisms to DHV-I infection in the duck. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed the highest level of CD8A expression to be in the thymus, followed by the lungs, spleen, and liver, and the levels of CD8A expression were very low in the kidney, cerebrum, cerebellum, and muscle in the duck. RT-qPCR also demonstrated that the CD8A mRNA was down-regulated significantly in morbid ducklings treated with DHV-1 and up-regulated significantly in non-morbid ducklings in all the tissues tested. In addition, hypermethylation of CD8A was detected in the morbid ducklings, whereas relatively low methylation of CD8A was evident in the non-morbid ducklings. The CD8A mRNA level was negatively associated with the CpG methylation level of CD8A and global methylation status.
  
  
  CONCLUSIONS
  We concluded that the mRNA level of the CD8A was negatively associated with the CpG methylation level of CD8A and global methylation status in the duck, suggesting that the hypermethylation of CD8A may be associated with DHV-1 infection. The first two CpG sites of the CD8A promoter region could be considered as epigenetic biomarkers for resistance breeding against duckling hepatitis disease in the duck.
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Qi
authors: Q
authors: Xu
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Yang
authors: Y
authors: Chen
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Wen Ming
authors: WM
authors: Zhao
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Zheng Yang
authors: ZY
authors: Huang
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Yang
authors: Y
authors: Zhang
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Xiu
authors: X
authors: Li
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Yi Yu
authors: YY
authors: Tong
authors: Guo Bin
authors: GB
authors: Chang
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Guo Bing
authors: GB
authors: Chang
authors: National Waterfowl Germplasm Resource Pool, Taizhou, People's Republic of China.
authors: Xiu Jun
authors: XJ
authors: Duan
authors: Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors: Guo Hong
authors: GH
authors: Chen
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000235:genetics*; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D004372:Ducks / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000235:genetics; D004371:Hepatitis Virus, Duck / Q000235:genetics*; D006524:Hepatitis, Viral, Animal / Q000235:genetics* / Q000821:virology; D010850:Picornaviridae Infections / Q000235:genetics* / Q000821:virology; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain; D012333:RNA, Messenger