RNA-guided assembly of Rev-RRE nuclear export complexes.

Area of Science:

• Molecular Biology
• Virology
• Structural Biology

Background:

• HIV replication necessitates the nuclear export of unspliced and singly spliced viral transcripts.
• The Rev-response element (RRE) is crucial for this viral mRNA export process.
• The mechanism by which multiple HIV Rev proteins assemble on the RRE to form an export complex has remained unclear.

Purpose of the Study:

• To elucidate the mechanism of HIV Rev-RRE complex assembly.
• To understand how RNA structural changes facilitate the recruitment of multiple Rev proteins.
• To investigate the kinetic pathway of viral export complex formation.

Main Methods:

• Selective 2'-hydroxyl acylation analyzed by primer extension sequencing (SHAPE-Seq) to probe RNA structure.
• Small-angle X-ray scattering (SAXS) to analyze the overall structure of the Rev-RRE complex.
• Kinetic analysis of Rev-RRE assembly.

Main Results:

• Initial Rev binding to the RRE induces significant RNA tertiary structural changes.
• These RNA rearrangements expose previously hidden binding sites for additional Rev proteins.
• The assembly occurs in two major kinetic steps, involving rapid initial binding followed by RNA remodeling and further protein recruitment.

Conclusions:

• The study reveals a dynamic mechanism for viral export complex formation, driven by RNA structural plasticity.
• This kinetic pathway ensures efficient and regulated assembly of the Rev-RRE complex.
• Understanding this process provides insights into maintaining the balance between HIV replication and maturation.