Research

A new example of viral intein in Mimivirus

Hiroyuki Ogata¹ , Didier Raoult² and Jean-Michel Claverie¹

¹  Information Génomique et Structurale, UPR2589 CNRS, IBSM, IFR88, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France

²  Unité des Rickettsies, CNRS UPRESA 6020, Faculté de Médecine, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France

author email corresponding author email

Virology Journal 2005, 2:8doi:10.1186/1743-422X-2-8

Published:	11 February 2005

Abstract

Background

Inteins are "protein introns" that remove themselves from their host proteins through an autocatalytic protein-splicing. After their discovery, inteins have been quickly identified in all domains of life, but only once to date in the genome of a eukaryote-infecting virus.

Results

Here we report the identification and bioinformatics characterization of an intein in the DNA polymerase PolB gene of amoeba infecting Mimivirus, the largest known double-stranded DNA virus, the origin of which has been proposed to predate the emergence of eukaryotes. Mimivirus intein exhibits canonical sequence motifs and clearly belongs to a subclass of archaeal inteins always found in the same location of PolB genes. On the other hand, the Mimivirus PolB is most similar to eukaryotic Polδ sequences.

Conclusions

The intriguing association of an extremophilic archaeal-type intein with a mesophilic eukaryotic-like PolB in Mimivirus is consistent with the hypothesis that DNA viruses might have been the central reservoir of inteins throughout the course of evolution.