Analysis of Human Immunodeficiency Virus Type 1 Integrase Mutants

Abstract

The human immunodeficiency virus type-1 (HIV-1) integrase protein (IN) mediates the insertion of linear double-stranded viral DNA into the host genome. Mutations in IN can have different effects on the virus life cycle. In this study, Gag-Pol polyprotein processing, Tat synthesis, and viral replication were investigated in integrase-defective HIV-1 mutants. In the absence of IN synthesis, the Gag-Pol polyprotein stability, packaging, and/or processing was reduced. There was limited expression of Tat observed in IN mutants, but no viral replication.

Human Immunodeficiency Virus Type 1 (HIV-1) Integrase: Resistance to Diketo Acid Integrase Inhibitors Impairs HIV-1 Replication and Integration and Confers Cross-Resistance to l -Chicoric Acid

“…In addition to mutations leading to defects in the in vitro integration reaction and delays in viral replication in tissue culture, mutations within IN can have pleiotropic effects on the life cycle. These include effects on reverse transcription, nuclear localization, proteolytic processing, and virion morphology (1,22,55,57). In the studies presented here, viruses containing mutations within IN, with the exception of HIV containing C280S, showed at least a slight delay in spread by IFA (Fig.…”

New insight on the role of extrachromosomal retroviral DNA

“…Indeed, circular E-DNA has been viral RNA is a better marker of HIV-1 replication and stage of the disease than is the decrease in CD4 + cell counts or the shown to be transcriptionally active, although at low levels and only for a short period of time. [34][35][36][37][38][39][40] In itself, this is not level of total viral DNA. 33 However, although amplification of extracellular RNA is necessary to quantitate the levels of surprising since both linear and circular E-DNA possess the promoter and termination signals essential for synthesis of serum-associated virus, testing for viral replication by analyzing the levels of intracellular RNA using RT-PCR introduces viral mRNA and consequently viral proteins.…”

“…Since has been determined in vivo, 18 does not permit them to be stable templates for viral mRNA transcription. Another reason recovery of RT activity after transient transfection of some INdefective molecular clones of HIV-1 is lower than that of the for the low contribution of E-DNA to the viral RNA pool is likely due to phenomena of promoter interference or wild-type counterpart, 34,36,39,43,44,48 it is likely that these mutants produce a lower amount of E-DNA, thus reducing the occlusion because of close proximity of the two promoters in the case of the c2LTR E-DNA, or the double use of the single amount of E-DNA template for mRNA transcription. LTR in c1LTR E-DNA to both start and terminate transcription.…”

“…terize the transcriptional activity of circular E-DNA. [34][35][36][37][38][39][40] INdefective viruses are unable to integrate reverse-transcribed circular DNA, producing only linear E-DNA in the cytoplasm Conclusions and circular E-DNA in the nuclei of the infected cells. Although this system is the closest to the situation in vivo, a While the production of E-DNA during the life cycle of retrogreat variability of transcriptional activity for circular E-DNA viruses is a well-established fact, their biological significance has been found when IN-defective viruses are used to infect is still a matter of controversy.…”

“…This indicates that the ability to sustain multiple rounds of infection is not only dependent on the transcriptional ability of unintegrated DNA References but also on the correct processing of viral proteins in the absence of a functional IN. 34,36,39,[43][44][45][46][47][48] 1 Varmus H, Swanstrom R. Replication of retroviruses. In: Weiss R,…”