Structure and replication cycle of a virus infecting climate-modulating alga Emiliania huxleyi

The globally distributed marine alga Emiliania huxleyi produces reflective calcite disks (coccoliths) that increase the albedo of ocean water and thus reduce the heat absorption in the ocean, which cools the Earth’s climate. The population density of E. huxleyi is restricted by Nucleocytoviricota viruses, including E. huxleyi virus 201 (EhV-201). Despite the impact of E. huxleyi viruses on the climate, there is limited information about their structure and replication. Here we show that the dsDNA genome inside the EhV-201 virion is protected by an inner membrane, capsid, and outer membrane decorated with numerous transmembrane proteins. The virions are prone to deformation, and parts of their capsids deviate from the icosahedral arrangement. EhV-201 virions infect E. huxleyi by using their fivefold vertex to bind to a host cell and fuse the virus’s inner membrane with the plasma membrane. Whereas the replication of EhV-201 probably occurs in the nucleus, virions assemble in the cytoplas..., , , # Structure and replication cycle of a virus infecting climate-modulating alga Emiliania huxleyi

1\) *Emiliania huxleyi* virus 201 life cycle visualization *in situ*:

* a) Cryo-electron tomography of lamellas of *Emiliania huxleyi* noncalcifying 2090 alga infected by *E. huxleyi* virus 201 (EhV-201) and control uninfected samples.
* b) Segmentation of two selected cryo-tomographic lamellae volumes (infected and control *E. huxleyi* cells).
* c) Block face imaging data of high-pressure frozen and resin-embedded samples of *E. huxleyi* infected by EhV-201.

2\) Scripts used during the reconstruction of EhV-201 by subtomogram averaging:

* a) TomoStarPy scripts available on GitHub (22 February 2024 clone):
* b) Script used for alignment of EhV-201 virion pentamer vertices during generation of virion composite map

3\) Super-resolution fluorescence data of EhV-201 attachment to the *E. huxleyi* cells.

4\) Proteomic analysis of EhV-201 virion - full report

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