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Updated: Dec 1, 2025

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes
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Published on: July 27, 2018

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Comparative Analysis of the Circular and Highly Asymmetrical Marseilleviridae Genomes

Léo Blanca1, Eugène Christo-Foroux1, Sofia Rigou1

  • 1CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Aix Marseille Univ., 13288 Marseille, France.

Viruses
|November 11, 2020
PubMed

Insights

Marseilleviridae viruses possess circular genomes, with distinct conserved and rearranged regions. Core genes cluster in the conserved region, suggesting roles in viral particle formation and late gene expression.

Area of Science:

  • Virology
  • Genomics
  • Microbiology

Background:

  • Marseilleviridae are large double-stranded DNA viruses infecting Acanthamoeba.
  • Their genomes range from 340-390 kb, encoding 450-550 genes.
  • Thirteen Marseilleviridae strains have been fully sequenced.

Purpose of the Study:

  • To experimentally confirm the circular nature of Marseilleviridae genomes.
  • To analyze genome organization and gene distribution through comparative genomics.
  • To investigate potential links between genome structure and viral replication.

Main Methods:

  • Experimental demonstration of circular DNA.
  • Comparative genomics of 13 sequenced Marseilleviridae strains.
  • Analysis of sequence conservation and gene distribution patterns.

Main Results:

  • Marseilleviridae genomes are experimentally confirmed as circular.
  • Two distinct genomic regions identified: one with rearrangements and paralogs, another with conserved core genes.
  • Genes for viral particle proteins are concentrated in the conserved region, showing late expression bias.

Conclusions:

  • Circular genome may offer advantages for Marseilleviridae replication.
  • Biased gene distribution suggests functional specialization related to transcription and DNA replication.
  • Further research is needed to characterize Marseilleviridae transcription and replication mechanisms.
Keywords:
comparative genomicsgenome evolutionlarge DNA virusesmarseillevirus

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