Viral Pandora's box – what can we learn from the largest viruses?

Abstract

Otkriće pandoravirusa uzdrmalo je temelje virusnog svijeta. Njihovo ime opisuje nedostatak sličnosti s postojećim mikrobima i iznenađenja koja može donijeti njihovo dalje istraživanje. S genomom od 2.5 Mb i 2556 kodirajućih sekvenci ruše sve rekorde virusne zajednice. Iako pretežito virusne prirode, posjeduju određene komponente translacijske mašinerije i mali dio proteina homologan proteinima bakterija, arheja i eukariota, što ih čini evolucijski naprednijim od ostalih poznatih virusa. Unatoč tome, najveći dio genoma pandoravirusa ostaje potpuna nepoznanica jer ne pokazuje nikakvu sličnost s ostalim genomima postojećih mikroba. Analizom B-obitelji DNA-polimeraza pokazalo se da pandoravirusi, i drugi gigantski virusi, filogenetski odmiču od postojećih organizama tvoreći četvrtu domenu života. Potrebna su daljnja istraživanja kako bi se utvrdilo je li zaista nađena poveznica između virusa i „živoga“ svijeta.The discovery of the Pandoraviruses has shaken up the postulates of the viral world. The name “Pandoravirus” describes a lack of similarity with the existing microbes and surprises one might expect from the further research. With the 2.5 Mb genome and 2556 protein-coding sequences, they break all the records in the world of viruses. Although they are viruses by nature, they possess some components of the translational machinery as well as a handful of proteins which are homologous to bacterial, archaeal and eukaryotic proteins. Such characteristics exhibit evolutionary advantage over other existing viruses. However, the majority of Pandoravirus genome remains a mystery because it does not show any similarity with the genomes of the existing organisms. The analysis of B family DNA polymerases showed that Pandoraviruses, and other gigantic viruses, are phylogenetically different from the other organisms and they cluster together to form a fourth domain of life. Additional research is necessary to establish whether Pandoraviruses are really the missing link between the viral and the “living” world