Retroviral integrase protein and intasome nucleoprotein complex structures

Area of Science:

• Structural Biology
• Virology
• Molecular Biology

Background:

• Retroviral replication involves integrating viral DNA into host genomes, a process mediated by integrase (IN).
• Understanding IN's catalytic functions historically required high-resolution structures of IN-DNA complexes (intasomes).
• The first functional intasome structure was determined for Prototype Foamy Virus (PFV) in 2010.

Purpose of the Study:

• To review the history of integrase structural biology.
• To compare the structures of PFV, Mouse Mammary Tumor Virus (MMTV), and Rous Sarcoma Virus (RSV) intasomes.
• To analyze the evolutionary adaptations in retroviral integration machineries.

Main Methods:

• Comparative structural analysis of retroviral intasomes.
• Review of historical integrase structural biology data.
• Analysis of IN protein assembly states (tetrameric vs. octameric).

Main Results:

• PFV intasome features a tetrameric IN assembly, while MMTV and RSV intasomes exhibit octameric assemblies.
• Despite differing higher-order architectures, MMTV and RSV intasomes share similar core structures.
• Retroviral integration machineries utilize diverse IN elements to achieve convergent intasome core structures.

Conclusions:

• Retroviral integrase has evolved diverse strategies to form functional intasomes.
• Convergent evolution has led to similar catalytic core structures across different retroviral intasomes.
• Structural insights into intasomes are crucial for understanding viral DNA integration.