A single amino acid substitution of the human immunodeficiency virus type 1 capsid protein affects viral sensitivity to TRIM5[alpha]

• Published in: Retrovirology 2010-07, Vol.7, p.58
• Main Authors: Kuroishi, Ayumu, Bozek, Katarzyna, Shioda, Tatsuo, Nakayama, Emi E
• Format: Article
• Language: English
• Subjects: Gene mutations; Genetic aspects; Health aspects; HIV (Viruses); Viral proteins
• ISSN: 1742-4690; 1742-4690
• DOI: 10.1186/1742-4690-7-58

Background Human immunodeficiency virus type 1 (HIV-1) productively infects only humans and chimpanzees but not Old World monkeys, such as rhesus and cynomolgus (CM) monkeys. To establish a monkey model of HIV-1/AIDS, several HIV-1 derivatives have been constructed. We previously reported that efficient replication of HIV-1 in CM cells was achieved after we replaced the loop between [alpha]-helices 6 and 7 (L6/7) of the capsid protein (CA) with that of SIVmac239 in addition to the loop between [alpha]-helices 4 and 5 (L4/5) and vif. This virus (NL-4/5S6/7SvifS) was supposed to escape from host restriction factors cyclophilin A, CM TRIM5[alpha], and APOBEC3G. However, the replicative capability of NL-4/5S6/7SvifS in human cells was severely impaired. Results By long-term cultivation of human CEMss cells infected with NL-4/5S6/7SvifS, we succeeded in rescuing the impaired replicative capability of the virus in human cells. Sequence analysis of the CA region of the adapted virus revealed a G-to-E substitution at the 116th position of the CA (G116E). Introduction of this substitution into the molecular DNA clone of NL-4/5S6/7SvifS indeed improved the virus' replicative capability in human cells. Although the G116E substitution occurred during long-term cultivation of human cells infected with NL-4/5S6/7SvifS, the viruses with G116E unexpectedly became resistant to CM, but not human TRIM5[alpha]-mediated restriction. The 3-D model showed that position 116 is located in the 6.sup.th .sup.helix near L4/5 and L6/7 and is apparently exposed to the protein surface. The amino acid substitution at the 116.sup.th .sup.position caused a change in the structure of the protein surface because of the replacement of G (which has no side chain) with E (which has a long negatively charged side chain). Conclusions We succeeded in rescuing the impaired replicative capability of NL-4/5S6/7SvifS and report a mutation that improved the replicative capability of the virus. Unexpectedly, HIV-1 with this mutation became resistant to CM TRIM5[alpha]-mediated restriction.