Cobbin, J. | bioRxiv Science

bioRxiv2021

Metagenomic identification of viral sequences in laboratory reagents

2.Metagenomic next-generation sequencing has transformed the discovery and diagnosis of infectious disease, with the power to characterize the complete infectome (bacteria, viruses, fungi, parasites) of an individual host organism. However, the identification of novel pathogens has been complicated by widespread microbial contamination in commonly used laboratory reagents. Using total RNA sequencing ("metatranscriptomics") we documented the presence of contaminant viral sequences in multiple libraries of blank negative control sequencing libraries that comprise a sterile water and reagent mix. Accordingly, we identified 14 viral sequences in 7 negative control sequencing libraries. As in previous studies, several circular replication-associated protein encoding (CRESS) DNA virus-like sequences were recovered in the blank libraries, as well as contaminating sequences from the RNA virus families Totiviridae, Tombusviridae and Lentiviridae. These data suggest that the contamination of common laboratory reagents is likely widespread and can comprise a wide variety of viruses. 3. Data summaryThe authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files. 1.5 RepositoriesThe viral genome sequence data generated in this study has been deposited in the NCBI database under accession numbers MZ824225-MZ824237. Sequence reads are available at the public Sequence Read Archive (SRA) database with accession SRX6803604 and under the BioProject accession PRJNA735051 reference numbers SRR14737466-71 and BioSample numbers SAMN20355437-40.

molecular biology↗

bioRxiv2021

The role of gene segment interactions in driving the emergence of dominant gene constellations during influenza virus reassortment

A segmented genome enables influenza virus to undergo reassortment when two viruses infect the same cell. Resulting reassorted progeny have a spectrum of gene constellations and potentially different phenotypes. Although reassortment is involved in the creation of pandemic influenza strains and is routinely used to produce influenza vaccines, our understanding of the factors that drive the emergence of dominant gene constellations during this process is incomplete. Using an influenza vaccine seed production model, reassortant genotypes were tracked through the reassortment process under antibody selective pressure. We discovered that certain gene constellations conferring low replicative fitness were selected at the expense of more fit progeny. Nevertheless, relatively unfit reassortants likely provide high hemagglutinin antigen yields through co-production of non-infectious particles and/or by more hemagglutinin molecules per virion. Our data illustrate the dynamics and complexity of reassortment and highlight how gene segment interactions formed during packaging, in addition to antibody pressure, restrict the final viruses that dominate.

microbiology↗