Nuclear Factor 90, a cellular dsRNA binding protein inhibits the HIV Rev-export function

Area of Science:

• Virology
• Molecular Biology
• Structural Biology

Background:

• The Human Immunodeficiency Virus (HIV) Rev protein is essential for viral replication, facilitating the export of viral transcripts from the nucleus to the cytoplasm.
• This export process relies on the interaction between Rev and the Rev-responsive element (RRE) RNA structure within viral transcripts.
• The C-terminal variant of dsRNA-binding nuclear protein 90 (NF90ctv) has demonstrated potential in attenuating HIV replication.

Purpose of the Study:

• To investigate the mechanism by which NF90ctv interferes with the HIV life cycle.
• To elucidate the interaction between the HIV Rev protein and NF90ctv.
• To determine how NF90ctv affects Rev-mediated nucleocytoplasmic transport of viral RNA.

Main Methods:

• Co-expression of NF90ctv and Rev protein in HeLa cells.
• Assessment of Rev-mediated RNA transport inhibition.
• Identification of specific regions within NF90ctv involved in blocking Rev function.
• Analysis of NF90ctv interaction with RRE RNA.
• Investigation of Rev's influence on NF90ctv subcellular localization.

Main Results:

• NF90ctv expression inhibited Rev-mediated RNA transport in HeLa cells.
• Three distinct regions of NF90ctv were identified as crucial for blocking Rev function.
• NF90ctv binding to RRE RNA affected reporter protein expression.
• Rev influenced the subcellular localization of NF90ctv in a leptomycin B-sensitive manner.

Conclusions:

• NF90ctv competes with HIV Rev function at both protein-protein and protein-RNA interaction levels.
• NF90ctv binds to specific domains of Rev and also interacts with the RRE RNA structure.
• These interactions disrupt Rev multimerization, a critical step in Rev-mediated HIV-1 RNA export.