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Updated: Sep 5, 2025
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Vaccinia Virus Infection & Temporal Analysis of Virus Gene Expression: Part 1
Published on: April 8, 2009
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Gene copy number variations at the within-host population level modulate gene expression in a multipartite virus
Romain Gallet1, Jérémy Di Mattia1, Sébastien Ravel1
1PHIM, Univ Montpellier, INRAE, CIRAD, IRD, Institut Agro, Montpellier, France.
Virus Evolution
|July 8, 2022
Summary
Multipartite viruses like faba bean necrotic stunt virus (FBNSV) adjust gene expression by altering their genome formula. This involves changing gene copy numbers, not DNA sequences, to adapt to different host plants.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Multipartite viruses possess segmented genomes where each segment is packaged separately.
- The relative frequencies of these segments, termed the 'genome formula', are host-dependent and reproducible.
- Genome formula variations are hypothesized to regulate gene expression through gene copy number changes.
Purpose of the Study:
- To investigate if multipartite genome organization facilitates gene expression regulation via genome formula modulation.
- To determine the relationship between genome formula and gene expression in faba bean necrotic stunt virus (FBNSV).
Main Methods:
- FBNSV was inoculated into faba bean and alfalfa hosts.
- Relative concentrations of DNA segments and their corresponding messenger RNAs (mRNAs) were monitored.
- Deep sequencing was used to analyze viral lineages after host transfer.
Main Results:
- Genome formula variations were shown to modulate gene expression in a host-dependent manner.
- A linear, positive correlation was observed between genome segment concentration and its cognate mRNA.
- Host switching induced changes in transcription rates, but the genome formula compensated to maintain mRNA ratios, independent of sequence mutation.
Conclusions:
- Nanoviruses exhibit plasticity, adjusting gene expression in response to environmental changes.
- This adaptation occurs by modulating the copy number of genome segments, not by altering their DNA sequences.
- The genome formula serves as a mechanism for transient gene expression regulation in nanoviruses.
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