Human immunodeficiency virus type-1 （HIV-1） regulatory Tat protein plays an crucial part in viral replication and infectivity. Throughout acute infection， Tat protein is released extracellularly by infected cells and is taken up by neighboring cells where it transactivates viral replication and inhances virus infectivity.
HIV-1 Tat activates transcription of HIV-1 viral genes by inducing phosphorylation of the C-terminal domain （CTD） of RNA polymerase II （RNAPII）. Tat can also disturb cellular metabolism by inhibiting proliferation of antigen-specific T lymphocytes and by inducing cellular apoptosis. Tat-induced apoptosis of T-cells is attributed， in part， to the distortion of microtubules polymerization. LIS1 is a microtubule-associated protein that facilitates microtubule polymerization.
Lyophilized HIV-1 TAT Cys22 although stable at room temperature for 1 week， should be stored desiccated below -18℃. Upon reconstitution HIV-1 TAT Cys22 should be stored at 4℃ between 2-7 days and for future use below -18℃.
For long-term storage it is recommended to add a carrier protein （0.1% HSA or BSA）.
Please prevent freeze-thaw cycles.
