Scaling relation between genome length and particle size of viruses provides insights into viral life history

Harshali V Chaudhari,Mandar M Inamdar,Kiran Kondabagil

doi:10.1016/j.isci.2021.102452

Harshali V Chaudhari, Mandar M Inamdar + Show 1 more

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https://doi.org/10.1016/j.isci.2021.102452

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Journal: iScience	Publication Date: Apr 21, 2021
Citations: 15	License type: cc-by

Affiliation: Indian Institute of Technology Bombay

Abstract

SummaryIn terms of genome and particle sizes, viruses exhibit great diversity. With the discovery of several nucleocytoplasmic large DNA viruses (NCLDVs) and jumbo phages, the relationship between particle and genome sizes has emerged as an important criterion for understanding virus evolution. We use allometric scaling of capsid volume with the genome length of different groups of viruses to shed light on its relationship with virus life history. The allometric exponents for icosahedral dsDNA bacteriophages and NCDLVs were found to be 1 and 2, respectively, indicating that with increasing capsid size DNA packaging density remains the same in bacteriophages but decreases for NCLDVs. We argue that the exponents are largely shaped by their entry mechanism and capsid mechanical stability. We further show that these allometric size parameters are also intricately linked to the relative energy costs of translation and replication in viruses and can have further implications on viral life history.

Highlights

Viruses are obligate intracellular parasites that infect most cellular organisms in the biosphere
With the discovery of several nucleocytoplasmic large DNA viruses (NCLDVs) and jumbo phages, the relationship between particle and genome sizes has emerged as an important criterion for understanding virus evolution
The allometric relation between the bacteriophages and NCLDVs is quite different, owing to statistical fluctuations a few data points from smaller NCLDVs and larger bacteriophages seem to be mixed in this region. This prompted us to ask a very naive question: given this overlap, are there any similarities between jumbo phages and smaller NCLDVs? Surprisingly, we found that jumbo phages have an ancestry that is significantly branched off from both smaller bacteriophages and NCLDVs (Yuan and Gao, 2017)

Summary

Introduction

Viruses are obligate intracellular parasites that infect most cellular organisms in the biosphere. The simplicity of their makeup allows them to adapt and evolve rapidly to infect different life forms. They lie in a disconcerting line between the living and the nonliving. A convincing argument on the origin and diversification of viruses remains elusive. With the discovery of several new lineages of large complex viruses and the availability of viral genomic information, this paradigm is being reconsidered (Boyer et al, 2010; Koonin and Starokadomskyy, 2016; Forterre, 2017)

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