Niemeyer Virus: A New Mimivirus Group A Isolate Harboring a Set of Duplicated Aminoacyl-tRNA Synthetase Genes

Abstract

It is well recognized that gene duplication/acquisition is a key factor for molecular evolution, being directly related to the emergence of new genetic variants. The importance of such phenomena can also be expanded to the viral world, with impacts on viral fitness and environmental adaptations. In this work we describe the isolation and characterization of Niemeyer virus, a new mimivirus isolate obtained from water samples of an urban lake in Brazil. Genomic data showed that Niemeyer harbors duplicated copies of three of its four aminoacyl-tRNA synthetase genes (cysteinyl, methionyl, and tyrosyl RS). Gene expression analysis showed that such duplications allowed significantly increased expression of methionyl and tyrosyl aaRS mRNA by Niemeyer in comparison to APMV. Remarkably, phylogenetic data revealed that Niemeyer duplicated gene pairs are different, each one clustering with a different group of mimivirus strains. Taken together, our results raise new questions about the origins and selective pressures involving events of aaRS gain and loss among mimiviruses.

Analyses of the Kroon Virus Major Capsid Gene and Its Transcript Highlight a Distinct Pattern of Gene Evolution and Splicing among Mimiviruses

“…Electron microscopy and morphometric assays enabled us to observe a great number of viral particles, with a pseudoicosahedral symmetry, fibrils surrounding the capsid, and a size that is comparable to that which has been observed in other studies involving mimivirus isolation (7,8,(11)(12)(13). These mimivirus-like particles presented an average size of 673.43 nm in total, fibers of about 128.9 nm, and a capsid size of 433.2 nm, spread along the acanthamoebal cytoplasm ( Fig.…”

“…Members of the family Mimiviridae have been isolated worldwide from an increasing variety of samples (7,8,10,12,13). As demonstrated in other studies, environments where there are high concentrations of organic matter seem to work as hot spots, marking the presence of a great diversity of mimiviruses, which is probably related to the suitable habitat for their amoebal host to live (8,19). In this study, we have managed to obtain another mimivirus isolate belonging to lineage A of the family Mimiviridae.…”

“…2D). Finally, the phylogenetic characterization of our isolate, for both the RNA helicase and DNA polymerase genes, has clustered it with members of lineage A from Mimiviridae, which includes Acanthamoeba castellanii mamavirus, mimivirus Terra2, Niemeyer virus, Samba virus, and oyster virus, among others (8,9,13,18) ( Fig. 3).…”

“…Amoeba giant viruses belonging to the Mimivirus genus (Mimiviridae family) were first described in 2003, during a characterization study of a pathogenic amoebaassociated microorganism that was related to outbreaks of nosocomial pneumonia in a hospital in Bradford, England (7). Since then, a large diversity of related viruses has been isolated from many different places (8)(9)(10)(11)(12)(13). As new giant viruses were being described, these organisms started to be phylogenetically classified based on the sequence of the gene related to DNA polymerase B.…”

An approach to the photocatalytic mechanism in the TiO2-nanomaterials microorganism interface for the control of infectious processes

“…5b, but some viruses such as the Megavirus chilensis can reach up to 750 nm [149]. 5b, but some viruses such as the Megavirus chilensis can reach up to 750 nm [149].…”