Related Experiment Video

Updated: Jun 21, 2026

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods
10:40

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods

Published on: December 21, 2019

Insight into poliovirus genome replication and encapsidation obtained from studies of 3B-3C cleavage site mutants

Hyung Suk Oh1, Harsh B Pathak, Ian G Goodfellow

  • 1Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, 16802, USA.

Journal of Virology
|July 10, 2009
PubMed

Insights

A poliovirus mutant unable to produce key proteins replicated RNA but failed to produce infectious virus, revealing a critical step in viral replication dependent on specific proteins. This finding sheds light on poliovirus assembly.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Poliovirus (PV) replication involves complex polyprotein processing and genome replication.
  • Specific viral proteins, including 3AB, VPg, and 3CD, are crucial for these processes.
  • Defects in cleavage sites can lead to non-functional viral proteins and altered replication.

Purpose of the Study:

  • To investigate the replication and assembly defects of a poliovirus mutant (GG) with a defective 3B-3C cleavage site.
  • To elucidate the role of 3CD and 3AB proteins in the late stages of poliovirus multiplication.
  • To determine if 3CD protein possesses trans-complementable functions in picornavirus replication.

Main Methods:

  • Characterization of a poliovirus mutant (GG) with a defective 3B-3C cleavage site.
  • Analysis of RNA replication, protein processing, and infectious virus production.
  • Use of a pseudorevertant (EG) and ectopic expression of 3CD protein to study specific functions.

Main Results:

  • The GG mutant replicated RNA but produced significantly less infectious virus due to a post-replication, pre-assembly block dependent on 3CD and/or 3AB.
  • 3BC-linked RNA was efficiently encapsidated, indicating the block occurs after replication but before or during assembly.
  • Ectopic expression of 3CD rescued genome replication but not infectious virus production, suggesting a distinct role in replication complex formation.

Conclusions:

  • A critical step in poliovirus production, following genome replication and preceding assembly, is dependent on 3CD and/or 3AB proteins.
  • This step may involve the release of replicated genomes from replication complexes.
  • The 3CD protein has a trans-complementable function essential for poliovirus genome replication, likely through interaction with viral/host factors.

More Related Videos

Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells10:22

Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells

Published on: November 12, 2015

Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus09:08

Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus

Published on: July 27, 2021

Related Concept Videos

DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Inhibitors of Virion Maturation and Assembly01:19

Inhibitors of Virion Maturation and Assembly

As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...
Size and Structure of Viral Genomes01:26

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...