A functional interaction between Rev and yeast pre-mRNA is related to splicing complex formation

Area of Science:

• Molecular Biology
• Virology
• Yeast Genetics

Background:

• The Human Immunodeficiency Virus type 1 (HIV-1) Rev protein is crucial for regulating viral gene expression.
• Rev facilitates the export of unspliced or partially spliced viral RNA to the cytoplasm.
• This function relies on Rev's interaction with a specific viral RNA structure, the Rev response element (RRE).

Purpose of the Study:

• To investigate the mechanism of Rev-mediated regulation of viral gene expression.
• To determine if Rev's function can be recapitulated in a heterologous system, the yeast Saccharomyces cerevisiae.
• To explore the role of the spliceosome in Rev's activity.

Main Methods:

• Reconstitution of HIV-1 Rev-mediated gene expression regulation in yeast.
• Utilizing reporter gene assays to assess Rev activity and RRE dependence.
• Introducing mutations in splice sites and branch points of reporter pre-mRNA to study epistatic effects.

Main Results:

• HIV-1 Rev enhances yeast pre-mRNA translation in an RRE-dependent manner.
• Rev's RNA binding and effector domains are essential for its function in yeast.
• Mutations affecting spliceosome assembly prevent Rev responsiveness, indicating a pre-spliceosome interaction.

Conclusions:

• Rev-mediated regulation of viral gene expression can be studied in yeast.
• Key components interacting with Rev are conserved between yeast and mammals.
• Rev likely interacts with the pre-mRNA in the context of the spliceosome during its function.