title: Viral and cellular requirements for the budding of feline endogenous retrovirus RD-114.
abstract: BACKGROUND
  RD-114 virus is a feline endogenous retrovirus and produced as infectious viruses in some feline cell lines. Recently, we reported the contamination of an infectious RD-114 virus in a proportion of live attenuated vaccines for dogs and cats. It is very difficult to completely knock out the RD-114 proviruses from cells, as endogenous retroviruses are usually integrated multiply into the host genome. However, it may be possible to reduce the risk of contamination of RD-114 virus by regulating the viral release from cells.
  
  
  RESULTS
  In this study, to understand the molecular mechanism of RD-114 virus budding, we attempted to identify the viral and cellular requirements for RD-114 virus budding. Analyses of RD-114 L-domain mutants showed that the PPPY sequence in the pp15 region of Gag plays a critical role in RD-114 virus release as viral L-domain. Furthermore, we investigated the cellular factors required for RD-114 virus budding. We demonstrated that RD-114 virus release was inhibited by overexpression of dominant negative mutants of Vps4A, Vps4B, and WWP2.
  
  
  CONCLUSIONS
  These results strongly suggest that RD-114 budding utilizes the cellular multivesicular body sorting pathway similar to many other retroviruses.
authors.affiliation: Department of Emerging Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Fukuma
authors.forename: Masumi
authors.initials: M
authors.lastname: Abe
authors.forename: Shuzo
authors.initials: S
authors.lastname: Urata
authors.forename: Rokusuke
authors.initials: R
authors.lastname: Yoshikawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Morikawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Miyazawa
authors.forename: Jiro
authors.initials: J
authors.lastname: Yasuda
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D002415:Cats; D002460:Cell Line; D020077:Endogenous Retroviruses / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000821:virology; D057146:Multivesicular Bodies / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly; D057074:Virus Release
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; C465283:WWP2 protein, human; D044767:Ubiquitin-Protein Ligases; D000251:Adenosine Triphosphatases