AEGiS-07IAC: Generation of high amounts of replicative defective infectious SIV by transcomplementation of a mutated rev with HTLV-1 rex.

7th International AIDS Conference

Florence, Italy — June 16-21, 1991

Generation of high amounts of replicative defective infectious SIV by transcomplementation of a mutated rev with HTLV-1 rex.

Int Conf AIDS 1991 Jun 16-21; 7:27 (abstract no. M.A.23)
Krohn K, Hakkarainen K, Aavik E, Dewhurst S, Sadaie R, Mullins J; University of Tampere, Tampere, Finland

OBJECTIVE: Genetically engineered replication deficient viruses can theoretically be used as attenuated vaccines. In HIV and SIV, the rev protein is known to be necessary for expression of viral structural proteins and for the production of infectious virus. We have determined the ability of HTLV-1 rex protein to complement for a non-expressed rev protein in SIV.

METHODS: Rev defective infectious clones HIV-I(pHXB2 107) and SIVSMM PBj 1.5 were used to transfect Hela, Hela-rev or Hela-rex cell lines. The supernatants were collected at day three and used to infect MT-4 cells, the latter of which are abortively infected with HTLV-I. Northern and western blotting, p24 antigen determination and infectivity assays were used to monitor expression of viral mRNA and proteins as well as infectious virus.

RESULTS: Transfection of Hela cells with the rev defective HIV or SIV clones resulted in no virus production. In contrast, both Hela-rev and Hela-rex cell lines yielded moderate or high amounts, respectively, of infectious virus, when transfected with p107 or PBj 1.5. Infection of MT-4 cells with the cell free supernatants from transfected Hela-rev or Hela-rex, but not from Hela cultures, resulted in extremely high production of replicative defective, infectious virus (greater than 10(9) particles/ml, 10(5)-10(6) TCIU/ml).

CONCLUSIONS: We have shown that HTLV-I rex transcomplements for SIV rev. The action of rev is thought to be mediated through an arginine rich motif that binds to the RRE in ENV mRNA. Similar motifs are found in other RNA binding proteins regulating the expression and transport of mRNA. A promiscuous rev-like sequence PPBRPPRRBXB (P=polar, B=basic, X=anything), present in rev from HIV-I, HIV-II and SIV as well as in HTLV-I, is proposed.

Keywords: AEGIS, SIV, Human T-lymphotropic virus 1, Gene Products, rex, Gene Products, rev, Virus Replication, HIV-1, HIV, Transfection, Hela Cells, HIV-2, Vaccines, Attenuated, RNA-Binding Proteins, RNA, Messenger, Human, virology, genetics, ICA7
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