Virus-induced double-membrane vesicles.

Many viruses that replicate in the cytoplasm compartmentalize their genome replication and transcription in specific subcellular microenvironments or organelle-like structures, to increase replication efficiency and protect against host cell defences. Recent studies have investigated the complex membrane rearrangements induced by diverse positive-strand RNA viruses, which are of two morphotypes : membrane invagination towards the lumen of the endoplasmic reticulum (ER) or other specifically targeted organelles and double-membrane vesicles (DMVs) formed by extrusion of the ER membrane. DMVs resemble small autophagosomes and the viruses inducing these intriguing organelles are known to promote autophagy, suggesting a potential link between DMVs and the autophagic pathway. In this review, we summarize recent findings concerning the biogenesis, architecture and role of DMVs in the life cycle of viruses from different families and discuss their possible connection to autophagy or other related pathways.