title: Modulation of the expression of mimivirus-encoded translation-related genes in response to nutrient availability during Acanthamoeba castellanii infection.
abstract: The complexity of giant virus genomes is intriguing, especially the presence of genes encoding components of the protein translation machinery such as transfer RNAs and aminoacyl-tRNA-synthetases; these features are uncommon among other viruses. Although orthologs of these genes are codified by their hosts, one can hypothesize that having these translation-related genes might represent a gain of fitness during infection. Therefore, the aim of this study was to evaluate the expression of translation-related genes by mimivirus during infection of Acanthamoeba castellanii under different nutritional conditions. In silico analysis of amino acid usage revealed remarkable differences between the mimivirus isolates and the A. castellanii host. Relative expression analysis by quantitative PCR revealed that mimivirus was able to modulate the expression of eight viral translation-related genes according to the amoebal growth condition, with a higher induction of gene expression under starvation. Some mimivirus isolates presented differences in translation-related gene expression; notably, polymorphisms in the promoter regions correlated with these differences. Two mimivirus isolates did not encode the tryptophanyl-tRNA in their genomes, which may be linked with low conservation pressure based on amino acid usage analysis. Taken together, our data suggest that mimivirus can modulate the expression of translation-related genes in response to nutrient availability in the host cell, allowing the mimivirus to adapt to different hosts growing under different nutritional conditions.
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Lorena C F
authors.initials: LC
authors.lastname: Silva
authors.affiliation: AQUACEN - Laboratório Nacional de Referencia para Doenças de Animais Aquáticos, Ministério da Pesca e Aquicultura, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Gabriel M F
authors.initials: GM
authors.lastname: Almeida
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Felipe L
authors.initials: FL
authors.lastname: Assis
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Jonas D
authors.initials: JD
authors.lastname: Albarnaz
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Paulo V M
authors.initials: PV
authors.lastname: Boratto
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Fábio P
authors.initials: FP
authors.lastname: Dornas
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Ketyllen R
authors.initials: KR
authors.lastname: Andrade
authors.affiliation: URMITE CNRS UMR 6236 - IRD 3R198, Aix Marseille Université Marseille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: La Scola
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Erna G
authors.initials: EG
authors.lastname: Kroon
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil ; Laboratório de Virologia Básica e Aplicada, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Flávio G
authors.initials: FG
authors.lastname: da Fonseca
authors.affiliation: Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
authors.forename: Jônatas S
authors.initials: JS
authors.lastname: Abrahão
keywords: aminoacyl-tRNA-synthetases; gene expression; mimivirus; tRNA; translation