HIV-1 Tat directly interacts with the interferon-induced, double-stranded RNA-dependent kinase, PKR.

We present evidence that the HIV-1 Tat protein and the RNA-dependent cellular protein kinase, PKR, interact with each other both in vitro and in vivo. Using GST fusion chromatography, we demonstrate that PKR, interacts directly with the HIV-1 Tat protein. The region in Tat sufficient for binding PKR maps within amino acids 20 to 72.

Characterization of an interferon-induced 48-kD protein immunologically related to the double-stranded RNA-activated protein kinase PKR.

Polyclonal antibodies raised against purified and urea-denatured double-stranded protein kinase (PKR) from human origin cross-reacted by immunoblotting with a 48-kD protein (p48) induced by the three types of interferon (IFN), alpha, beta, and gamma. The induction of p48 is IFN dose dependent and its accumulation occurs a few hours after the addition of IFN. The induction of p48 is blocked by actinomycin D.

HIV-2 EHO isolate has a divergent envelope gene and induces single cell killing by apoptosis.

The human immunodeficiency virus type 2 (HIV-2)-related isolate, referred to as HIV-2 EHO, has been isolated from an Ivory Coast patient with acquired immunodeficiency syndrome (AIDS). Infection of CD4 expressing cells with this highly infectious virus mediates a cytopathic effect characterized by single-cell killing as a consequence of apoptosis. Nucleotide sequence analysis of the HIV-2 EHO genome revealed a significant degree of divergence of its envelope gene from that of other known HIV-2 strains.