The natural history of mimiviruses (i.e., viruses that are members of the Mimivirus genus) is a challenge for modern biology. A new domain of life to include these organisms has been proposed from analysis of gene conservation. We analyzed the evolutionary relationship of proteins involved in the translation system, and our data show that mimiviruses are a sister group of Eukarya. New data about the origins of Eukarya, in which Eukarya appears as a branch derived from the Archaea domain, were discussed, and we suggest that the mimiviruses emerged from the initial population that gave origin to Eukarya and that, in this way are not part of a new domain of life.
Studies involving miRNAs have opened discussions about their broad participation in viral infections. Regarding the Human gammaherpesvirus 4 or Epstein-Barr virus (EBV), miRNAs are important regulators of viral and cellular gene expression during the infectious process, promoting viral persistence and, in some cases, oncogenic processes. We identified 55 miRNAs of EBV type 2 and inferred the viral mRNA target to self-regulate. This data indicate that gene self-repression is an important strategy for maintenance of the viral latent phase. In addition, a protein network was constructed to establish essential proteins in the self-regulation process. We found ten proteins that work as hubs, highlighting BTRF1 and BSRF1 as the most important proteins in the network. These results open a new way to understand the infection by EBV type 2, where viral genes can be targeted for avoiding oncogenic processes, as well as new therapies to suppress and combat the persistent viral infection.
Abstract:The hypothesis that Mutual Information (MI) dendrograms of influenza A viruses reflect informational groups generated during viral evolutionary processes is put forward. Phylogenetic reconstructions are used for guidance and validation of MI dendrograms. It is found that MI profiles display an oscillatory behavior for each of the eight RNA segments of influenza A. It is shown that dendrograms of MI values of geographically and historically different segments coming from strains of RNA virus influenza A turned out to be unexpectedly similar to the clusters, but not with the topology of the phylogenetic trees. No matter how diverse the RNA sequences are, MI dendrograms crisply discern actual viral subtypes together with gain and/or losses of information that occur during viral evolution. The amount of information during a century of evolution of RNA segments of influenza A is measured in terms of bits of information for both human and avian strains. Overall the amount of information of segments of pandemic strains oscillates during viral evolution. To our knowledge this is the first description of clades of information of the viral subtypes and the estimation of the flow content of information, measured in bits, during an evolutionary process of a virus.
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