title: The CD8α gene in duck (Anatidae): cloning, characterization, and expression during viral infection.
abstract: Cluster of differentiation 8 alpha (CD8α) is critical for cell-mediated immune defense and T-cell development. Although CD8α sequences have been reported for several species, very little is known about CD8α in ducks. To elucidate the mechanisms involved in the innate and adaptive immune responses of ducks, we cloned CD8α coding sequences from domestic, Muscovy, Mallard, and Spotbill ducks using reverse transcription polymerase chain reaction (RT-PCR). Each sequence consisted of 714 nucleotides and encoded a signal peptide, an IgV-like domain, a stalk region, a transmembrane region, and a cytoplasmic tail. We identified 58 nucleotide differences and 37 amino acid differences among the four types of duck; of these, 53 nucleotide and 33 amino acid differences were between Muscovy ducks and the other duck species. The CD8α cDNA sequence from domestic duck consisted of a 61-nucleotide 5' untranslated region (UTR), a 714-nucleotide open reading frame, and an 849-nucleotide 3' UTR. Multiple sequence alignments showed that the amino acid sequence of CD8α is conserved in vertebrates. RT-PCR revealed that expression of CD8α mRNA of domestic ducks was highest in the thymus and very low in the kidney, cerebrum, cerebellum, and muscle. Immunohistochemical analyses detected CD8α on the splenic corpuscle and periarterial lymphatic sheath of the spleen. CD8α mRNA in domestic ducklings was initially up-regulated, and then down-regulated, in the thymus, spleen, and liver after treatment with duck hepatitis virus type I (DHV-1) or the immunostimulant polyriboinosinic polyribocytidylic acid (poly I:C).
authors.affiliation: Key Laboratory of Animal Genetics and Breeding and Molecular Design of Jiangsu Province, Yangzhou University, Yangzhou, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xu
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Wen Ming
authors.initials: WM
authors.lastname: Zhao
authors.forename: Zheng Yang
authors.initials: ZY
authors.lastname: Huang
authors.forename: Xiu Jun
authors.initials: XJ
authors.lastname: Duan
authors.forename: Yi Yu
authors.initials: YY
authors.lastname: Tong
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiu
authors.initials: X
authors.lastname: Li
authors.forename: Guo Bin
authors.initials: GB
authors.lastname: Chang
authors.forename: Guo Hong
authors.initials: GH
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016827:CD8 Antigens / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004372:Ducks / Q000235:genetics* / Q000821:virology; D015870:Gene Expression; D004371:Hepatitis Virus, Duck; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain; D018076:DNA, Complementary; D012333:RNA, Messenger