Updating and Testing the Viral Eukaryogenesis Theory for the Origin of the Eukaryotes

Type: 
Seminar
Date: 
Wednesday 20 June, 2018
Time: 
2.00pm
Location: 
Biosciences Building (D26), Level 3, Room 356, Rountree Room

Explaining the deep chasm that exists in cellular design between the eukaryotes and prokaryotes remains a major scientific challenge. A membrane bound nucleus defines the eukaryotic domain and its presence contributes significantly to the observed eukaryote/prokaryote divide. Although the origin of the eukaryotic nucleus is unresolved, the Viral Eukaryogenesis hypothesis proposes that the eukaryotic nucleus is viral in origin. The recent discovery of nucleus-like viral factories constructed by bacteriophage 201Φ2-1 provides support for this hypothesis since the viral factories share deep similarities with the nucleus including establishment of a eukaryote-like separation of transcription from translation. One prediction of the VE hypothesis is that the genes utilised by the eukaryotic nucleus to separate transcription from translation should be viral in origin. Two eukaryotic specific enzymes enable the eukaryotic separation of transcription from translation: the guanylyltransferase enzyme that caps eukaryotic mRNA, and the cap binding protein (EIF4E) that initiates translation of capped mRNA in the cytoplasm. Here it is shown that both genes are found in NCLDV viruses but are not found in either bacteria or archaea, including Lokiarchaeota, a specific archaeal relative of the eukaryotes. Phylogenetic analysis reveals the eukaryotic and viral genes descend from a common ancestor that predated the Last Eukaryotic Common Ancestor (LECA). These findings are consistent with the predictions of the VE hypothesis. In this talk the VE hypothesis is updated in light of these and other recent scientific advances.

Biography: Dr Philip Bell is Director of Research at Microbiogen where he leads programs to develop improved yeast biocatalysts for biofuel production. He co-founded Microbiogen in 2001 with Dr Paul Attfield with the aim of using non-GM evolutionary principles to improve the performance of yeast under industrial conditions. Microbiogen is a current recipient of an Australian Renewable Energy Grant (ARENA) to develop world leading biocatalysts for producing ethanol from lignocellulosic waste materials such as sugarcane bagasse. He has published over 20 peer reviewed publications in fields ranging from yeast genetics, flow cytometry, fluorescent probes, lipase cloning, corn ethanol production and the origin of the eukaryotes.