Background: HIV-1 TAT protein is essential for the regulation of viral genome transcription.
The first exon of TAT protein has a fundamental role in the stimulation of the extrinsic
and intrinsic apoptosis pathways, but its anti-HIV activity is not clear yet.
Methods: In the current study, we firstly cloned the first exon of the TAT coding sequence in the
pET-24a expression vector and then protein expression was done in the Rosetta expression host.
Next, the expressed TAT protein was purified by Ni-NTA column under native conditions. After
that, the protein yield was determined by Bradford kit and NanoDrop spectrophotometry. Finally,
the cytotoxicity effect and anti-Scr-HIV-1 activity of the recombinant TAT protein alone and along
with Tenofovir drug were assessed by MTT and ELISA, respectively.
Results: The recombinant TAT protein was successfully generated in E. coli, as confirmed by
13.5% SDS-PAGE and western blotting. The protein yield was ~150-200 μg/ml. In addition, the recombinant
TAT protein at a certain dose with low toxicity could suppress Scr-HIV replication in
the infected HeLa cells (~30%) that was comparable with a low toxic dose of Tenofovir drug
(~40%). It was interesting that the recombinant TAT protein could enhance anti-HIV potency of
Tenofovir drug up to 66%.
Conclusion: Generally, a combination of TAT protein and Tenofovir drug could significantly inhibit
HIV-1 replication. It will be required to determine their mechanism of action in the next