Structural studies demonstrating a bacteriophage-like replication cycle of the eukaryote-infecting Paramecium bursaria chlorella virus-1

PLoS Pathogens

Katya Rechav¹  Eyal Shimoni¹  Tali Dadosh¹  James L. Van Etten²  Abraham Minsky³  Elad Milrot³  Tamar Unger⁴ 

[1] Chemical Research Support, The Weizmann Institute of Science, Rehovot, Israel;Department of Plant Pathology and Nebraska Center for Virology, University of Nebraska, Lincoln, NE, United States of America;Department of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel;Proteomics, The Weizmann Institute of Science, Rehovot, Israel

关键词: Cell membranes;    Viral genomics;    Host cells;    Chloroplasts;    Viral packaging;    Viral genome;    Cytoplasm;    Bacteriophages;   

DOI  :  10.1371/journal.ppat.1006562

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

A fundamental stage in viral infection is the internalization of viral genomes in host cells. Although extensively studied, the mechanisms and factors responsible for the genome internalization process remain poorly understood. Here we report our observations, derived from diverse imaging methods on genome internalization of the large dsDNA Paramecium bursaria chlorella virus-1 (PBCV-1). Our studies reveal that early infection stages of this eukaryotic-infecting virus occurs by a bacteriophage-like pathway, whereby PBCV-1 generates a hole in the host cell wall and ejects its dsDNA genome in a linear, base-pair-by-base-pair process, through a membrane tunnel generated by the fusion of the virus internal membrane with the host membrane. Furthermore, our results imply that PBCV-1 DNA condensation that occurs shortly after infection probably plays a role in genome internalization, as hypothesized for the infection of some bacteriophages. The subsequent perforation of the host photosynthetic membranes presumably enables trafficking of viral genomes towards host nuclei. Previous studies established that at late infection stages PBCV-1 generates cytoplasmic organelles, termed viral factories, where viral assembly takes place, a feature characteristic of many large dsDNA viruses that infect eukaryotic organisms. PBCV-1 thus appears to combine a bacteriophage-like mechanism during early infection stages with a eukaryotic-like infection pathway in its late replication cycle.

【 授权许可】

CC BY