Mimivirus and Mimiviridae revive the historical debate on the true nature of viruses — ASN Events
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Mimivirus and Mimiviridae revive the historical debate on the true nature of viruses (#34)

Chantal Abergel 1 , Jean-Michel Claverie 1
  1. Information Génomique et Structurale, CNRS-AMU, Marseille, France

The discovery of Mimivirus (for “Mimicking Microbe” virus), a double-stranded DNA virus infecting common amoeba of the Acanthamoeba genus, followed by the analysis of its complete genome (in 2003) sent a shock wave through the community of virologists and evolutionists. By its record particle size (750 nm in diameter) and genome length (1.2 million bp), the complexity of its gene repertoire (911 protein coding genes) as well as of its particle (made of the products of more than 130 virus genes), Mimivirus blurred the established boundaries between viruses and parasitic cellular organisms. As more researchers are getting involved in the study of Mimivirus, experimental information has been accumulating on its prevalence in the environment. The Mimiviridae family is now extensively studied revealing a peculiar infectious cycle. Unique regulatory elements are governing the viral genes expression and are processed by peculiar virally encoded enzymes. The Mimiviridae cytoplasmic replicative cycle make these giant viruses the target of viral infection reactivating the debate on viruses’ true nature. Are viruses viruses after all ?

  1. Raoult D, Audic S, Robert C, Abergel C, Renesto P, Ogata H, La Scola B, Suzan M, Claverie JM. (2004) The 1.2-megabase genome sequence of Mimivirus. Science.;306:1344-50.
  2. Arslan D, Legendre M, Seltzer V, Abergel C, Claverie JM. A distant relative with a larger genome highlights the fundamental features of Megaviridae. Proc Natl Acad Sci U S A 2011;108:17486-91.
  3. Legendre M, Audic S, Poirot O, Hingamp P, Seltzer V, Byrne D, Lartigue A, Lescot M, Bernadac A, Poulain J, Abergel C, Claverie JM. (2010) mRNA deep sequencing reveals 75 new genes and a complex transcriptional landscape in Mimivirus. Genome Res.;20:664-74.
  4. Byrne D, Grzela R, Lartigue A, Audic S, Chenivesse S, Encinas S, Claverie JM, Abergel C. (2009) The polyadenylation site of Mimivirus transcripts obeys a stringent 'hairpin rule'. Genome Res.;19:1233-42.
  5. La Scola B, Desnues C, Pagnier I, Robert C, Barrassi L, Fournous G, Merchat M, Suzan-Monti M, Forterre P, Koonin E, Raoult D. The virophage as a unique parasite of the giant mimivirus. Nature. 2008 Sep 4;455(7209):100-4.
  6. Priet S, Lartigue A, Debart F, Claverie JM, Abergel C. mRNA maturation in giant viruses: variation on a theme. Nucleic Acids Res. 2015 Mar 16. pii: gkv224.
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