Transmembrane regions of bovine herpesvirus 1-encoded UL49.5 and glycoprotein M regulate complex maturation and ER–Golgi trafficking

Investigation of the Effects of Primary Structure Modifications within the RRE Motif on the Conformation of Synthetic Bovine Herpesvirus 1‐Encoded UL49.5 Protein Fragments

“…All cell lines were obtained as described before [41] . Briefly, a QuikChange Lightning Site‐Directed Mutagenesis Kit (Agilent Technologies, USA) with oligonucleotides listed in Table 2 were used to introduce point mutations into the UL49.5 sequence in the plasmid pCDNA3‐IRES‐NLS‐GFP‐UL49.5 [7] .…”

The Roles of Envelope Glycoprotein M in the Life Cycle of Some Alphaherpesviruses

“…Altogether, these findings suggest that the fusion process regulated by gM may be related to other proteins (König et al, 2002;Kim et al, 2013), and also shows that highly specialized and precise strategies have developed during pathogen entry into the cells, which reflects the process of mutual struggle and common progress between host and virus (Crump et al, 2004;White et al, 2008;Gomes et al, 2018). 1) Viral genome is assembled into the capsid to form the nucleocapsid (Skepper et al, 2001); (2) The nucleocapsid acquires a small number of tegument proteins in the nucleus (Baines et al, 2007;Wills et al, 2009); (3) Immature virions budding in the inner nuclear membrane and enter the perinuclear space, meanwhile, gM is assembled into the primary envelope (Baines et al, 2007;Zhang et al, 2009); (4) The primary envelope is de-envelopment at the outer membrane and the naked nucleocapsid is released into the cytoplasm; (5) The naked nucleocapsid acquires a large number of tegument proteins in the cytoplasm (Johnson and Baines, 2011;Maringer et al, 2012); (6) gD, gH, and gL located on the surface of cell membrane were internalized by gM and relocated to Golgi apparatus (Ren et al, 2012); (7) gN and gM located in the endoplasmic reticulum (ER) form complex and matures, and then transfer to Golgi apparatus (Graul et al, 2019); (8) The nucleocapsid is wrapped by tegument proteins and obtained the ultimate envelope at the Golgi apparatus (Turcotte et al, 2005); ( 9)-(10) The vesicles derive from Golgi apparatus and wrap the enveloped virions and transported them to the cell membrane (Sugimoto et al, 2008); (11) Progeny virions released by exocytosis at cell membrane (Turcotte et al, 2005;Johnson and Baines, 2011); and (12) gM antagonized the tetherin and virions were successfully released (Blasius et al, 2006)…”

“…The nascent proteins' subcellular location depends on its trafficking motifs, indicating that the protein might contain corresponding functions. gM can locate various membrane structures (Crump et al, 2004;Baines et al, 2007;Graul et al, 2019). gM may be recruited by UL31 and UL34 or an unknown mechanism unrelated with rearrangement of Golgi apparatus to reside in inner nuclear membrane (Turcotte et al, 2005;Desai et al, 2008;Wills et al, 2009;Zhang et al, 2009), and it is clear that gM nuclear exit requires XPO6 at late times.…”

“…gM, as an important protein of the envelope, has a homologous compound in the whole herpesviruses, which can interact with other viral components to form an interaction network and aid in forming a complete virion structure. The gM/gN complex exists in many herpesviruses (e.g., HSV-1, PRV, and BHV-1) and can be connected by a covalent disulfide bond between cysteine residues and non-covalent bond (Mach et al, 2005;Sadaoka et al, 2010;Striebinger et al, 2016), in BoHV-1, the glycine zipper motifs within transmembrane helices of gM are required for the ER release and maturation of the gM/gN complex, and it also interacts with other cellular proteins (Graul et al, 2019), such as soluble N-ethylmaleimide-sensitive factor attachment protein receptors (v-SNARE) and vesicle-associated membrane protein 3 (VAMP3; Kawabata et al, 2014;Wang et al, 2017), which facilitate the transport protein complex between membraneenclosed intracellular organelles, thanks to technological advances, weak or transient but specific interactions between gM and nearly 60 proteins can now be detected using a proximity-dependent method (Boruchowicz et al, 2020). Therefore, these interaction relationships not only facilitate gM/ gN transport from the ER to the Golgi apparatus and incorporate into the virion through the secondary envelopment, but also integrate the cell components into the virion and assist the progeny virions in entering the cell (Jahn and Scheller, 2006;van den Bogaart et al, 2010).…”

Alphaherpesvirus gB Homologs Are Targeted to Extracellular Vesicles, but They Differentially Affect MHC Class II Molecules

“…Twenty-two fractions (0.5 mL, with the top fraction) were collected from top to bottom and analyzed. The number of infectious virus particles in each fraction was determined by a plaque assay on Vero (HSV-1), MDBK (BoHV-1) or SK6 (PRV) cells, as described in [29].…”