title: Chicken cyclophilin A is an inhibitory factor to influenza virus replication.
abstract: BACKGROUND
  The importance of enhancing influenza resistance in domestic flocks is quite clear both scientifically and economically. Chicken is very susceptible to influenza virus. It has been reported that human cellular cyclophilin A (CypA) impaired influenza virus infection in 293T cells. Whether chicken CypA (chCypA) inhibits influenza virus replication is not known. The molecular mechanism of resistance in chicken to influenza virus remains to be studied.
  
  
  RESULTS
  The chCypA gene was isolated and characterized in the present study. It contained an ORF of 498 bp encoding a polypeptide of 165 amino acids with an estimated molecular mass of 17.8 kDa sharing high identity with mammalian CypA genes. The chCypA demonstrated an anti-influenza activity as expected. ChCypA protein was shown to be able to specifically interact with influenza virus M1 protein. Cell susceptibility to influenza virus was reduced by over-expression of chCypA in CEF cells. The production of recombinant influenza virus A/WSN/33 reduced to one third in chCypA expressing cells comparing to chCypA absent cells. ChCypA was widely distributed in a variety of chicken tissues. It localized in cytoplasm of chicken embryo fibroblast (CEF) cells. Avian influenza virus infection induced its translocation from cytoplasm into nucleus. ChCypA expression was not significantly up-regulated by avian influenza virus infection. The present study indicated that chCypA was an inhibitory protein to influenza virus replication, suggesting a role as an intrinsic immunity factor against influenza virus infection.
  
  
  CONCLUSIONS
  The present data demonstrates that chCypA possesses anti-influenza virus activity which allows the consideration of genetic improvement for resistance to influenza virus in chickens.
authors.affiliation: Graduate University of Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Chongfeng
authors.initials: C
authors.lastname: Xu
authors.forename: Shanshan
authors.initials: S
authors.lastname: Meng
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002645:Chickens; D021984:Cyclophilin A / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000254:growth & development / Q000502:physiology*; D053127:Influenza A Virus, H9N2 Subtype / Q000254:growth & development / Q000502:physiology*; D005585:Influenza in Birds / Q000378:metabolism / Q000821:virology*; D008969:Molecular Sequence Data; D021381:Protein Transport; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014763:Viral Matrix Proteins / Q000378:metabolism; D014779:Virus Replication
chemical_list: C488936:M1 protein, Influenza A virus; D014763:Viral Matrix Proteins; D021984:Cyclophilin A