H-TYR-GLY-ARG-LYS-LYS-ARG-ARG-GLN-ARG-ARG-ARG-OH

HIV-1 trans-activator of transcription (Tat) is an 11kDa protein, which regulates HIV-1 gene expression at the level of transcription and protein synthesis. It is located in the nucleus of infected cells. HIV-1 Tat functions as a transcriptional activator for the synthesis of full-length viral RNA. It induces RNA splicing. Tat is an RNA binding protein, which particularly recognizes trans activator response element (TAR) from the HIV-1 RNA molecule.

Synthetic peptide that includes the sequence responsible for the cellular uptake of the human immunodeficiency virus-1 Tat protein, consisting of the polycationic region 49–57. The peptide is part of the protein transduction domain (PTD) and was shown to enable the introduction of nucleic acids into cells.