CONSENSUS B Tat Fragments
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Online Inquiry
Human immunodeficiency virus type 1 (HIV-1) encodes structural and regulatory proteins that play an important role in the pathogenesis of AIDS. Among these regulatory proteins, TAT is a small (14 KDa) 86-to 101-amino-acid nuclear protein, which is necessary for efficient transcription and viral replication of HIV-1 provirus. The carboxyl terminal fragment of human immunodeficiency virus type 1 (HIV-1) TAT protein, including a conserved region rich in arginine and lysine, specifically binds to the transactivation RNA sequence (TAR). A chemically synthesized peptide of 14 residues can also recognize TAR, across the basic subdomain to determine that this subdomain is the center of RNA interaction. Tar RNA forms a stable hairpin consisting of a ring of six residues, a trinucleotide pyrimidine bulge, and a wide range of double-stranded structures. Competition and interference experiments showed that the fragments derived from TAT bound to double-stranded RNA and specifically interacted with pyrimidine protruding and adjacent double-stranded tar.
Application of Tat Fragments
Despite the nuclear localization and function of TAT and the absence of any secretory signal sequence, TAT is released by infected cells in vitro and can bind and transfer to the cell membranes of uninfected cells from different bystanders. Extracellular TAT has a variety of immunosuppressive functions. Such as inhibiting the production of interleukin-12 by human peripheral blood mononuclear cells (PBMCs), producing interferon, inhibiting the proliferation of T cells with mitogen or antigen, and inducing the expression of HIV-1 coreceptor, as well as many other harmful biological effects. Low levels of extracellular TAT, were detected in 33 patients with HIV infection, but TAT was physiologically active in vitro at these concentrations. Asymptomatic patients with high anti-TAT antibody titers who progress slowly have been reported and reduced with AIDS symptoms. Innate immunoglobulin M (IgM) antibodies against two identified TAT sequences can also provide preliminary defense against the pathological effects of extracellular TAT after HIV infection.
Conclusion
Recent studies have also found that TAT core peptides also play an important role in promoting the high expression of foreign proteins. The high efficient and soluble expression level of exogenous protein was significantly increased, which showed the new function of TAT protein transfer peptide. TAT protein transduction peptide mediated transmembrane transduction of exogenous biological macromolecules is a complex multi-factor regulatory process. By optimizing its transmembrane transduction factors, we can not only reorganize its own structure, but also develop new transmembrane transduction peptides and so on.
References
- Spector, C., Mele, A. R., Wigdahl, B., & Nonnemacher, M. R. (2019). Genetic variation and function of the HIV-1 Tat protein. Medical microbiology and immunology, 1-39.
- Weeks, K. M., Ampe, C., Schultz, S. C., Steitz, T. A., & Crothers, D. M. (1990). Fragments of the HIV-1 Tat protein specifically bind TAR RNA.;Science, 249(4974), 1281-1285.
