title: Inhibitory effect of human TRIM5alpha on HIV-1 production.
abstract: Tripartite motif-containing 5 isoform-alpha (TRIM5alpha), a host restriction factor, blocks infection of some retroviruses at a post-entry, pre-integration stage in a species-specific manner. A recent report by Sakuma et al. describes a second antiretroviral activity of rhesus macaque TRIM5alpha, which blocks HIV-1 production through rapid degradation of HIV-1 Gag polyproteins. Here, we find that human TRIM5alpha limits HIV-1 production. Transient expression of TRIM5alpha decreased HIV-1 production, whereas knockdown of TRIM5alpha in human cells increased virion release. A single amino acid substitution (R437C) in the SPRY domain diminished the restriction effect. Moderate levels of human wild-type TRIM5alpha and a little amount of R437C mutant were incorporated into HIV-1 virions. The R437C mutant also lost restriction activity against N-tropic murine leukemia virus infection. However, the corresponding R to C mutation in rhesus macaque TRIM5alpha had no effect on the restriction ability. Our findings suggest human TRIM5alpha is an intrinsic immunity factor against HIV-1 infection. The importance of arginine at 437 aa in SPRY domain for the late restriction is species-specific.
authors.affiliation: Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo 060-0815, Japan.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Zhang
authors.forename: Mariko
authors.initials: M
authors.lastname: Kondo
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyoshi
authors.forename: Hajime
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohashi
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Shida
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000276:immunology*; D002478:Cells, Cultured; D055785:Gene Knockdown Techniques; D015497:HIV-1 / Q000254:growth & development* / Q000276:immunology*; D006801:Humans; D008253:Macaca mulatta; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases
chemical_list: D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins; D000070584:Tripartite Motif Proteins; C477346:TRIM5 protein, human; D044767:Ubiquitin-Protein Ligases