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Order Articulavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
Therefore, most of the basic approaches described earlier for expressing influenza VLPs included M1 protein, because M1 was the most abundant protein in the virion and because it has been shown initially to be the driving force of influenza virus budding (Gómez-Puertas et al. 2000). By the baculovirus-driven expression in insect cells, the influenza VLPs that contained the HA protein only were reported first by Choi et al. (2013). Pushko et al. (2015) generated in insect cells the H7 HA subviral particles of ∼20 nm in diameter composed of approximately 10 HA0 molecules, while no significant quantities of free monomeric HA0 were observed in preparations. Such particles protected mice and ferrets from challenge with H7N9 influenza virus (Pushko et al. 2015).
Human Influenza Virus Infections
Published in Sunit K. Singh, Human Respiratory Viral Infections, 2014
Judith M. Fontana, Daniel P. Eiras, Mirella Salvatore
Influenza viral assembly is believed to occur at the site of specialized lipid domains, or rafts, on the apical plasma membrane in polarized epithelial cells (Figure 22.2).35 These lipid rafts are enriched in cholesterol, sphingolipids, and phospholipids containing fatty acids, and have been shown to play a role in the entry, assembly, and budding of many viruses.36 In influenza virus, the M1 protein orchestrates viral assembly at lipid rafts.35 Although not a membrane-spanning protein, M1 may attach to the plasma membrane through the cooperative action of several binding sites, and is a determinant for virion morphology because of its interactions with all other viral proteins.35,37 The HA and NA surface proteins bind weakly to the M1 protein and are intrinsically recruited to lipid rafts, where interactions with other M1 proteins increase the strength of these interactions.38–40 The M2 protein is excluded from lipid rafts,39 but may be incorporated into the virion through direct interactions with the M1 protein.41,42 Following replication of the viral genome, the newly formed vRNA assembles with the NP, PB1, PB2, and PA proteins, which accumulate in the nucleus after their translation, to form the vRNP.43,44 With the assistance of NEP, the vRNP is subsequently exported from the nucleus to the cytoplasm,45 and though the mechanism for vRNP transport to the site of viral assembly is unknown, the M1 protein may be involved through its interaction with NP.46,47 The M1 protein may also interact with NEP, resulting in its incorporation in small amounts into the virion.48,49 The final virion includes a complete set of eight distinct vRNPs that are arranged as seven segments of varying lengths surrounding one central segment.50
Variant influenza: connecting the missing dots
Published in Expert Review of Anti-infective Therapy, 2022
Vivek Chavda, Rajashri Bezbaruah, Tutumoni Kalita, Anupam Sarma, Juti Rani Devi, Ratnali Bania, Vasso Apostolopoulos
The seventh segment of vRNA specifies the matrix protein (M1) and the ion channel protein (M2). An organized layer is created below the membrane of the virus by the M1 protein, which connects the virus’s envelope and core (vRNP). M2 constitutes a proton channel-forming multi-functional membrane protein [27,30]. The M2 and M1 proteins must work together to allow the virus to invade the host cell for the release of RNP. The activity of the M2 ion channel increases as soon as the virus enters the cell of the host, and the virion is released from the endosome, increasing the flow of positively charged molecules and acidification [36]. Viral internal acidification causes the breaking of the HA-M1 link and uncoating of the virus particles, which is followed by HA inclusion with the endosomal membrane and initiation of viral RNA production [27].
Platelet interaction with bacterial toxins and secreted products
Published in Platelets, 2015
Streptococcus pyogenes sepsis is associated with haemostasis dysfunction [86]. M protein is a cell wall-anchored protein of S. pyogenes that participates in multiple aspects of virulence [87]. The M protein of S. pyogenes emm1 serotype can also be released into the extracellular medium through the action of bacterial and host proteases [88, 89]. This soluble M1-protein forms a complex with plasma fibrinogen and this complex has been detected in abscess material from a patient suffering from S. pyogenes sepsis [90]. The M1 protein is a powerful platelet agonist. The M protein–fibrinogen complex binds to the surface of resting platelets and stimulates platelet activation [91, 92]. An inter-individual variation in the ability of platelets to become activated in response to M protein has been observed and this is correlated to the level of anti-M protein IgG present in the individual’s plasma. This may represent an important strategy to cause thrombi at a distance from the bacteria and avoid entrapment of the bacteria in platelet aggregates. Furthermore, platelet thrombi may occlude the vessels and contribute to organ damage in sepsis.
Molecular engineering tools for the development of vaccines against infectious diseases: current status and future directions
Published in Expert Review of Vaccines, 2023
Wenhui Xue, Tingting Li, Ying Gu, Shaowei Li, Ningshao Xia
Si et al. designed a novel PROTAC virus vaccine by incorporating a protein-targeting domain (PTD) that includes a proteasome-targeting peptide and a tobacco etch virus protease (TEVp) recognition site. They introduced PTD into the influenza A virus genome and fused it with the M1 protein, allowing TEVp to specifically cleave M1-PTD and enable the normal assembly of virus particles. In the absence of TEVp, however, M1-PTD is degraded by the ubiquitin-proteasome system, rendering the virus incapable of self-replication in conventional cells. The PROTAC virus vaccine exhibited a high level of attenuation in mouse and ferret models while eliciting robust and broad immune responses against homologous and heterologous viruses [101].