The 3.3 Å structure of a plant geminivirus using cryo-EM

Abstract

Geminiviruses are major plant pathogens that threaten food security globally. They have a unique architecture built from two incomplete icosahedral particles, fused to form a geminate capsid. However, despite their importance to agricultural economies and fundamental biological interest, the details of how this is realized in 3D remain unknown. Here we report the structure of Ageratum yellow vein virus at 3.3 Å resolution, using single-particle cryo-electron microscopy, together with an atomic model that shows that the N-terminus of the single capsid protein (CP) adopts three different conformations essential for building the interface between geminate halves. Our map also contains density for ~7 bases of single-stranded DNA bound to each CP, and we show that the interactions between the genome and CPs are different at the interface than in the rest of the capsid. With additional mutagenesis data, this suggests a central role for DNA binding-induced conformational change in directing the assembly of geminate capsids.

Collection, pre-processing and on-the-fly analysis of data for high-resolution, single-particle cryo-electron microscopy

“…A low magnification atlas is then taken of the grid to help identify regions of appropriate ice thickness for data collection (Step 26). The areas for automated collection are then selected (27)(28)(29)(30).…”

Plant-virus-insect tritrophic interactions: insights into the functions of geminivirus virion-sense strand genes

“…by seven bases of viral single stranded DNA (ssDNA) as shown for a monopartite begomovirus [9]. Upon geminivirus infection, the uncoating of viral ssDNA takes place in the cytoplasm of the infected plant cell, followed by wrapping of the viral DNAs by the CP.…”

Phosphorylations of the Abutilon Mosaic Virus Movement Protein Affect Its Self-Interaction, Symptom Development, Viral DNA Accumulation, and Host Range

“…Geminiviruses constitute an economically important group of plant-infecting viruses (Rojas et al, 2018;Garcia-Arenal and Zerbini, 2019). Their genomes consist of either one or two (DNA-A & DNA-B) circular single-stranded (ss) DNA molecules, which are packaged into uniquely shaped "geminate", i.e., double-icosahedral particles (Jeske, 2009;Hanley-Bowdoin et al, 2013;Hipp et al, 2017;Hesketh et al, 2018;Xu et al, 2019). Within nuclei of plant host cells, viral DNAs (vDNAs) replicate via double-stranded (ds) intermediates that adopt minichromosome organization (Pilartz and Jeske, 1992;Pilartz and Jeske, 2003;Jeske, 2009;Hanley-Bowdoin et al, 2013).…”