Since January 2020, Elsevier has created a free COVID-19 resource center with English and Mandarin information on the novel coronavirus. The center is hosted on Elsevier Connect, a public news and information website. Elsevier grants permission to make all its COVID-19-related research immediately available in PubMed Central and other public repositories for unrestricted reuse and analysis. The article discusses the composition and three-dimensional architecture of Dengue virus (DENV) replication and assembly sites. Using electron microscopy, researchers found that DENV-induced vesicles, convoluted membranes, and virus particles are derived from the endoplasmic reticulum (ER). Double-stranded RNA, a marker of RNA replication, was detected inside virus-induced vesicles. Electron tomography revealed that DENV-induced membrane structures are part of one ER-derived network. Vesicle pores may enable the release of newly synthesized viral RNA, and DENV particles bud from ER membranes adjacent to these pores. This architecture supports efficient replication and genome encapsulation. DENV modifies ER membranes to facilitate replication and efficient viral assembly. The study combines immuno-EM, thin-section TEM, and ET to determine the origin and structure of DENV-induced membranes. Results suggest that DENV replication and assembly sites are closely linked, with viral replication occurring in vesicles connected to the ER. The study also shows that DENV-induced membranes are derived from the ER, with ER markers like PDI and calnexin labeling these structures. The study reveals that DENV-induced membranes form a continuous network, with virus budding occurring near ER membranes. The vesicles are invaginations of the ER membrane, connected to the cytosol via pores, suggesting they are sites of viral RNA replication. The architecture of DENV replication and assembly sites may explain the coordination of distinct steps in the flavivirus replication cycle. The findings have implications for understanding the biogenesis and architecture of the replication complex (RC) in other flaviviruses, such as hepatitis C virus (HCV). The study provides insights into the spatial coupling of DENV replication steps and highlights the importance of membrane structures in viral replication and assembly.Since January 2020, Elsevier has created a free COVID-19 resource center with English and Mandarin information on the novel coronavirus. The center is hosted on Elsevier Connect, a public news and information website. Elsevier grants permission to make all its COVID-19-related research immediately available in PubMed Central and other public repositories for unrestricted reuse and analysis. The article discusses the composition and three-dimensional architecture of Dengue virus (DENV) replication and assembly sites. Using electron microscopy, researchers found that DENV-induced vesicles, convoluted membranes, and virus particles are derived from the endoplasmic reticulum (ER). Double-stranded RNA, a marker of RNA replication, was detected inside virus-induced vesicles. Electron tomography revealed that DENV-induced membrane structures are part of one ER-derived network. Vesicle pores may enable the release of newly synthesized viral RNA, and DENV particles bud from ER membranes adjacent to these pores. This architecture supports efficient replication and genome encapsulation. DENV modifies ER membranes to facilitate replication and efficient viral assembly. The study combines immuno-EM, thin-section TEM, and ET to determine the origin and structure of DENV-induced membranes. Results suggest that DENV replication and assembly sites are closely linked, with viral replication occurring in vesicles connected to the ER. The study also shows that DENV-induced membranes are derived from the ER, with ER markers like PDI and calnexin labeling these structures. The study reveals that DENV-induced membranes form a continuous network, with virus budding occurring near ER membranes. The vesicles are invaginations of the ER membrane, connected to the cytosol via pores, suggesting they are sites of viral RNA replication. The architecture of DENV replication and assembly sites may explain the coordination of distinct steps in the flavivirus replication cycle. The findings have implications for understanding the biogenesis and architecture of the replication complex (RC) in other flaviviruses, such as hepatitis C virus (HCV). The study provides insights into the spatial coupling of DENV replication steps and highlights the importance of membrane structures in viral replication and assembly.