title: Construction and characterization of an infectious molecular clone of Koala retrovirus.
abstract: Koala retrovirus (KoRV) is a gammaretrovirus that is currently endogenizing into koalas. Studies on KoRV infection have been hampered by the lack of a replication-competent molecular clone. In this study, we constructed an infectious molecular clone, termed plasmid pKoRV522, of a KoRV isolate (strain Aki) from a koala reared in a Japanese zoo. The virus KoRV522, derived from pKoRV522, grew efficiently in human embryonic kidney (HEK293T) cells, attaining 10(6) focus-forming units/ml. Several mutations in the Gag (L domain) and Env regions reported to be involved in reduction in viral infection/production in vitro are found in pKoRV522, yet KoRV522 replicated well, suggesting that any effects of these mutations are limited. Indeed, a reporter virus pseudotyped with pKoRV522 Env was found to infect human, feline, and mink cell lines efficiently. Analyses of KoRV L-domain mutants showed that an additional PPXY sequence, PPPY, in Gag plays a critical role in KoRV budding. Altogether, our results demonstrate the construction and characterization of the first infectious molecular clone of KoRV. The infectious clone reported here will be useful for elucidating the mechanism of endogenization of the virus in koalas and screening for antiretroviral drugs for KoRV-infected koalas.
authors: Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Kyoto, Japan. takavet@gmail.com
authors: Takayuki
authors: T
authors: Shojima
authors: Shigeki
authors: S
authors: Hoshino
authors: Masumi
authors: M
authors: Abe
authors: Jiro
authors: J
authors: Yasuda
authors: Hiroko
authors: H
authors: Shogen
authors: Takeshi
authors: T
authors: Kobayashi
authors: Takayuki
authors: T
authors: Miyazawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002460:Cell Line; D003001:Cloning, Molecular; D017988:Gammaretrovirus / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D007564:Japan; D008907:Mink; D008969:Molecular Sequence Data; D048368:Phascolarctidae / Q000821:virology*; D012192:Retroviridae Infections / Q000662:veterinary* / Q000821:virology; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D057074:Virus Release; D014779:Virus Replication
chemical_list: D014764:Viral Proteins