Acetylation of HIV-1 integrase by p300 regulates viral integration

Abstract

Integration of HIV-1 into the human genome, which is catalyzed by the viral protein integrase (IN), preferentially occurs near transcriptionally active genes. Here we show that p300, a cellular acetyltransferase that regulates chromatin conformation through the acetylation of histones, also acetylates IN and controls its activity. We have found that p300 directly binds IN both in vitro and in the cells, as also specifically demonstrated by fluorescence resonance energy transfer technique analysis. This interaction results in the acetylation of three specific lysines (K264, K266, K273) in the carboxy-terminus of IN, a region that is required for DNA binding. Acetylation increases IN affinity to DNA, and promotes the DNA strand transfer activity of the protein. In the context of the viral replication cycle, point mutations in the IN acetylation sites abolish virus replication by specifically impairing its integration capacity. This is the first demonstration that HIV-1 IN activity is specifically regulated by post-translational modification.

Interaction between HIV-1 Rev and Integrase Proteins

“…The GST-IN expression vector was a generous gift from Dr. A. Cereseto (20). The histidine-tagged IN expression vector was a generous gift from Dr. A. Engelman and its expression and purification were performed essentially as described previously (21).…”

“…Protein Expression and Purification-Expression and purification of histidine-tagged Rev-GFP and GST-IN conjugates were performed as previously described (19,20). The GST-IN expression vector was a generous gift from Dr. A. Cereseto (20).…”

Molecular Crosstalk between HIV-1 Integration and Host Proteins – Implications for Therapeutics

“…In addition to histones, HATs are able to acetylate other proteins including transcription factors. In vitro analysis using recombinant proteins showed that p300 can also acetylate three specific lysines (Lys264, Lys266, and Lys273) in the C-terminus of HIV-1 IN (Cereseto et al, 2005). Interestingly, the acetylation increased IN binding to LTR DNA its catalysis of the strand transfer reaction in vitro (Cereseto et al, 2005).…”

“…Posttranslational modifications of HIV-1 IN by cellular enzymes have also been reported to be implicated in integration. p300, a histone acetyltransferase (HAT), was first identified as a cellular protein that directly binds to HIV-1 IN in vitro and in human cells (Cereseto et al, 2005). HATs are known as enzymes that catalyze the transfer of acetyl groups from acetyl coenzyme A (acetyl-CoA) to specific lysine residues within the N-terminal tails of nucleosomal histones.…”

“…In vitro analysis using recombinant proteins showed that p300 can also acetylate three specific lysines (Lys264, Lys266, and Lys273) in the C-terminus of HIV-1 IN (Cereseto et al, 2005). Interestingly, the acetylation increased IN binding to LTR DNA its catalysis of the strand transfer reaction in vitro (Cereseto et al, 2005). Because HIV-1 harbouring mutations in the Lys264, Lys266, and Lys273 of IN exhibited replication defect at the integration step, these results suggest that acetylation of IN is important for efficient integration during HIV-1 infection (Cereseto et al, 2005).…”