20.109(F09): John and Ashley HIV Rev

Overall Research Goals: There has been significant study on the interaction between Rev and IN. There are two regions of IN that appear to bind to two different regions of Rev. These four areas have been identified and their protein sequence and position in the protein as a whole is known. It may be possible to create a library of mutagenized peptides using PCR of one of the known peptides. Using a Rev or IN inhibitor needs to be decided. Rev inhibitor does not seem to be focused on as of yet. Creating a Rev inhibitor which would increase the integration events might destabilize the cells enough in combination with other HIV-1 drugs to actually decrease HIV viability noticeably. Need to look up HIV drugs and determine if Rev is a target (does not seem to be for any currently on the market, but unsure about others in pipeline), and if so, how targeted.

Review of existing literature

Novel regulation of HIV-1 replication and pathogenicity: Rev inhibition of integration
Levin et al, 2009

Brief: This paper establishes relationship b/w Rev and IN, and proposes second role for Rev as inhibitor of IN

This paper was published extremely recently (10/29/09) and focuses on establishing the role of the Rev protein in HIV infected cells. Rev has been previously established as a protein that exports viral RNA from the nucleus. Before this study it was also established that Rev has an additional role of binding the protein Integrase (IN). IN is carried by the HIV virus and is responsible for integrating the viral genome into the host's. This study begins by establishing that these two proteins bind (via co-IP). These researchers also establish that Rev is expressed 6 hours post-insertion (PI) meaning that it is translated without being integrated into the genome. When Rev is expressed in wt cells, it inhibits the activity of integrase and results in 1-2 HIV genome integrations per cell. When Rev is absent the cells undergo as many as 13 integrations and have an increased rate of lysis which may indicate that there is genomic instability from so may insertions. Other retro viruses do insert many more copies than HIV, so it may turn out that HIV is able to still infect without Rev, but it might be weaker. So it remains to be determined whether HIV can recover, and if so how well, from Rev knowckout. When Rev is overexpressed there are 0-1 insertions. This data implies that Rev is responsible for maintaining a viable amount of virus integration so that HIV can prosper with in an organism.

Peptides Derived from HIV-1 Integrase that Bind Rev Stimulate Viral Genome Integration
Levin et al, 2007 This paper identified the 2 regions of Rev and In that bind and determines the sequence and position of these peptides. It appears as if it might be more effective to block IN through this interaction, because blocking Rev does not impact HIV efficacy in vitro. Of the two regions in IN identified, each binds to a different peptide identified from Rev. This paper would be useful in determining how to create peptides to mimic the binding sites because it identifies the target sites.

Interaction between HIV-1 Rev and Integrase Proteins
Rosenbluh et al, 2007

This paper is a precursor to the one above, but it focuses on the discovery of short peptides that inhibit IN activity by creating peptides that mimic Rev. They create two peptides based on IN-Rev binding sites and test their effect in vivo by using a galactosidase indicator and other assays. They found that both peptides inhibited HIV-1 replication in cultured cells.