PMID- 32956404 OWN - NLM STAT- MEDLINE DCOM- 20201013 LR - 20210618 IS - 1553-7374 (Electronic) IS - 1553-7366 (Print) IS - 1553-7366 (Linking) VI - 16 IP - 9 DP - 2020 Sep TI - The interplays between Crimean-Congo hemorrhagic fever virus (CCHFV) M segment-encoded accessory proteins and structural proteins promote virus assembly and infectivity. PG - e1008850 LID - 10.1371/journal.ppat.1008850 [doi] LID - e1008850 AB - Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne orthonairovirus that has become a serious threat to the public health. CCHFV has a single-stranded, tripartite RNA genome composed of L, M, and S segments. Cleavage of the M polyprotein precursor generates the two envelope glycoproteins (GPs) as well as three secreted nonstructural proteins GP38 and GP85 or GP160, representing GP38 only or GP38 linked to a mucin-like protein (MLD), and a double-membrane-spanning protein called NSm. Here, we examined the relevance of each M-segment non-structural proteins in virus assembly, egress and infectivity using a well-established CCHFV virus-like-particle system (tc-VLP). Deletion of MLD protein had no impact on infectivity although it reduced by 60% incorporation of GPs into particles. Additional deletion of GP38 abolished production of infectious tc-VLPs. The loss of infectivity was associated with impaired Gc maturation and exclusion from the Golgi, showing that Gn is not sufficient to target CCHFV GPs to the site of assembly. Consistent with this, efficient complementation was achieved in cells expressing MLD-GP38 in trans with increased levels of preGc to Gc conversion, co-targeting to the Golgi, resulting in particle incorporation and restored infectivity. Contrastingly, a MLD-GP38 variant retained in the ER allowed preGc cleavage but failed to rescue miss-localization or infectivity. NSm deletion, conversely, did not affect trafficking of Gc but interfered with Gc processing, particle formation and secretion. NSm expression affected N-glycosylation of different viral proteins most likely due to increased speed of trafficking through the secretory pathway. This highlights a potential role of NSm in overcoming Golgi retention and facilitating CCHFV egress. Thus, deletions of GP38 or NSm demonstrate their important role on CCHFV particle production and infectivity. GP85 is an essential viral factor for preGc cleavage, trafficking and Gc incorporation into particles, whereas NSm protein is involved in CCHFV assembly and virion secretion. FAU - Freitas, Natalia AU - Freitas N AUID- ORCID: 0000-0001-8821-561X AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Enguehard, Margot AU - Enguehard M AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Denolly, Solene AU - Denolly S AUID- ORCID: 0000-0003-1739-0079 AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Levy, Camille AU - Levy C AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Neveu, Gregory AU - Neveu G AUID- ORCID: 0000-0002-2363-6031 AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Lerolle, Solene AU - Lerolle S AUID- ORCID: 0000-0002-2859-4002 AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. FAU - Devignot, Stephanie AU - Devignot S AUID- ORCID: 0000-0002-0618-5611 AD - Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany. FAU - Weber, Friedemann AU - Weber F AUID- ORCID: 0000-0001-9737-337X AD - Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany. FAU - Bergeron, Eric AU - Bergeron E AUID- ORCID: 0000-0003-3398-8628 AD - Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America. FAU - Legros, Vincent AU - Legros V AUID- ORCID: 0000-0002-6118-7564 AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. AD - Universite de Lyon, VetAgro Sup, Marcy-l'Etoile, France. FAU - Cosset, Francois-Loic AU - Cosset FL AUID- ORCID: 0000-0001-8842-3726 AD - CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Universite Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, 46 allee d'Italie, Lyon, France. LA - eng GR - R01 AI151006/AI/NIAID NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20200921 PL - United States TA - PLoS Pathog JT - PLoS pathogens JID - 101238921 RN - 0 (Viral Structural Proteins) SB - IM MH - Cell Line, Tumor MH - Gene Deletion MH - Hemorrhagic Fever Virus, Crimean-Congo/*physiology MH - Humans MH - *Viral Structural Proteins/genetics/metabolism MH - *Virus Assembly PMC - PMC7529341 COIS- The authors have declared that no competing interests exist. EDAT- 2020/09/22 06:00 MHDA- 2020/10/21 06:00 PMCR- 2020/09/21 CRDT- 2020/09/21 17:14 PHST- 2020/03/13 00:00 [received] PHST- 2020/08/01 00:00 [accepted] PHST- 2020/10/01 00:00 [revised] PHST- 2020/09/22 06:00 [pubmed] PHST- 2020/10/21 06:00 [medline] PHST- 2020/09/21 17:14 [entrez] PHST- 2020/09/21 00:00 [pmc-release] AID - PPATHOGENS-D-20-00502 [pii] AID - 10.1371/journal.ppat.1008850 [doi] PST - epublish SO - PLoS Pathog. 2020 Sep 21;16(9):e1008850. doi: 10.1371/journal.ppat.1008850. eCollection 2020 Sep.