The features of Tat protein of human immunodeficiency virus type 1 (Retroviridae: ) non-A6 variants, characteristic for the Russian Federation.

Introduction: Tat protein is a trans-activator of HIV-1 genome transcription, with additional functions including the ability to induce the chronic inflammatory process. Natural amino acid polymorphisms in Tat may affect its functional properties and the course of HIV infection. The aim of this work is to analyze the marks of Tat consensus sequences in non-A6 HIV-1 variants characteristic of the Russian Federation, as well as study natural polymorphisms in Tat CRF63_02A6 and subtype B variants circulating in Russia.

Materials And Methods: The whole-genome nucleotide sequences of HIV-1 CRF63_02A6, CRF03_A6B, as well as subtype B and CRF02_AG circulating in Russia were used. The reference group was formed based on the sequences of subtype B variants circulating in different countries. Preferentially, the sequences were downloaded from the international database Los Alamos.

Results: CRF63_02A6 consensus sequence contained the highest number of amino acid substitutions, 31, and had no helix at positions 30‒33 in the secondary structure; however, this did not change its predicted tertiary structure. CRF03_A6B consensus sequence contained a stop codon at position 87. The polymorphisms in subtype B variants circulating in our country and in CRF63_02A6 variants were identified.

Conclusion: Consensus sequences of Tat protein in non-A6 variants typical for the Russian Federation were obtained and their features were determined. R78G, located in the functionally significant motif, and C31S, the functionally significant substitution, were significantly more frequent in subtype B variants circulating in Russia and in CRF63_02A6 variants than in the reference group, respectively. A limitation of this study is the small sample of sequences.