Getting order to the viral universe

Speaker: Dennis H. Bamford, University of Helsinki, Finland
Host: Peter Brodersen (Section for Computational and RNA Biology)

Abstract
Viruses are the most abundant living entities in the biosphere outnumbering their host organisms by one to two orders of magnitude. It is conceivable that they cause the highest selective pressure their hosts encounter. As obligate parasites viruses are dependent on their hosts but their origins seem to deviate from that of cellular life.

What are the possible structural principles to build viruses is an open question. However, structural studies on virus capsids and coat protein folds propose that there are only a limited number of ways to construct a virion. This limitation may be based on the limited protein fold space. Consequently, relatedness of viruses is not connected to the type of cells they infect and the same architectural principle of the capsid has been observed in viruses infecting bacteria as well as humans. Using the viral capsid architecture it is possible to group viruses to several structure based lineages that may have existed before the three cellular domains of life (bacteria, archaea and eukarya) were separated. This would mean that viruses are ancient and that early cells were already infected with many different types of viruses proposing that the origin of viruses is polyphyletic opposing to the monophyletic origin of cellular life. To test the hypothesis of limited viral structure space we have collected information on globally collected environmental viruses infecting archaea and bacteria and compared  the obtained information to known viral structures.

Related papers
Voloudakis A, Holeva M, Sarin LP, Bamford DH, Vargas M, Poranen MM, and Tenllado F. 2015. Efficient double-stranded RNA production methods for utilization in plant virus control. Methods Mol. Biol. 1236, p. 255-274.

Peralta B, Gil-Carton D, Castaño-Díez D, Bertin A, Boulogne C, Oksanen HM, Bamford DH and Abrescia NGA. 2013. Mechanism of membranous tunneling nanotube formation in viral genome delivery. PLoS Biol. 11:e1001667

Pietilä MK, Laurinmäki P, Russell DA, Ko C-C, Jacobs-Sera D, Hendrix RW, Bamford DH, and Butcher SJ. 2013. Structure of the archaeal head-tailed virus HSTV-1 compleates the HK97-fold story. Proc. Natl. Acad. Sci. USA. 110:10604-10609.