Plasmid-Based Reverse Genetics System Enabling One-Step Generation of Genotype 3 Hepatitis E Virus.

Area of Science:

• Virology
• Molecular Biology
• Public Health

Background:

• Hepatitis E virus (HEV) presents a significant global health challenge.
• Conventional reverse genetics systems for HEV are complex, multi-step, and prone to RNA degradation.
• Studying HEV replication and pathogenesis is hindered by these limitations.

Purpose of the Study:

• To develop a simplified, single-step, plasmid-based reverse genetics system for Hepatitis E virus (HEV).
• To enable efficient intracellular transcription and expression of the full-length HEV genome.
• To provide a versatile platform for HEV genetic engineering and research.

Main Methods:

• Developed a single-step, plasmid-based HEV expression system utilizing intracellular transcription under a CMV-IE promoter.
• Incorporated hammerhead (HH) and hepatitis delta virus (HDV) ribozymes for precise self-cleavage and authentic RNA termini generation.
• Introduced a genetic marker to assess the feasibility of targeted genetic modifications.

Main Results:

• The system supported HEV genome replication, viral protein expression, and progeny virion production comparable to traditional methods.
• A genetic marker was stably retained in progeny virions, confirming the potential for genetic manipulation.
• Plasmid-derived HEV showed delayed replication kinetics, potentially due to the lack of an immediate 5' cap.

Conclusions:

• The developed plasmid-based system simplifies HEV reverse genetics, facilitating research into HEV replication and pathogenesis.
• This platform offers a versatile tool for genetic engineering of the HEV genome.
• Further optimization, possibly through promoter design, may be needed to overcome replication delays.