Multiple UBXN family members inhibit retrovirus and lentivirus production and canonical NFκΒ signaling by stabilizing IκBα

Abstract

UBXN proteins likely participate in the global regulation of protein turnover, and we have shown that UBXN1 interferes with RIG-I-like receptor (RLR) signaling by interacting with MAVS and impeding its downstream effector functions. Here we demonstrate that over-expression of multiple UBXN family members decreased lentivirus and retrovirus production by several orders-of-magnitude in single cycle assays, at the level of long terminal repeat-driven transcription, and three family members, UBXN1, N9, and N11 blocked the canonical NFκB pathway by binding to Cullin1 (Cul1), inhibiting IκBα degradation. Multiple regions of UBXN1, including its UBA domain, were critical for its activity. Elimination of UBXN1 resulted in early murine embryonic lethality. shRNA-mediated knockdown of UBXN1 enhanced human immunodeficiency virus type 1 (HIV) production up to 10-fold in single cycle assays. In primary human fibroblasts, knockdown of UBXN1 caused prolonged degradation of IκBα and enhanced NFκB signaling, which was also observed after CRISPR-mediated knockout of UBXN1 in mouse embryo fibroblasts. Knockout of UBXN1 significantly up- and down-regulated hundreds of genes, notably those of several cell adhesion and immune signaling pathways. Reduction in UBXN1 gene expression in Jurkat T cells latently infected with HIV resulted in enhanced HIV gene expression, consistent with the role of UBXN1 in modulating the NFκB pathway. Based upon co-immunoprecipitation studies with host factors known to bind Cul1, models are presented as to how UBXN1 could be inhibiting Cul1 activity. The ability of UBXN1 and other family members to negatively regulate the NFκB pathway may be important for dampening the host immune response in disease processes and also re-activating quiescent HIV from latent viral reservoirs in chronically infected individuals.

UBXN3B positively regulates STING-mediated antiviral immune responses

“…Indeed, by using different genome editing technologies, we and collaborators independently find that Ubxn3b -null mutation is embryonically lethal 24 . In agreement with our findings, another UBA-UBX gene, UBXN1 , is also essential for embryonic development 34 . The genes essential for embryonic/neonatal stages are generally believed to be essential for adult stage too.…”

UBXN1 interacts with the S1 protein of transmissible gastroenteritis coronavirus and plays a role in viral replication

“…The binding of UBXN1 to MAVS interferes with intracellular MAVS oligomerization and blocks the formation of the MAVS/TRAF3/TRAF6 signalosome to inhibit the type I IFN response [2]. It has been confirmed that the N terminus of UBXN1 is responsible for binding to MAVS (aa 438–467) and that UBXN1’s functions in ubiquitination are independent of binding to VCP/p97 [30].…”

A Multiplex CRISPR/Cas9 System for Use as an Anti-BmNPV Therapeutic

“…This has helped the genetic traits of multiple genes and the knockout of family genes [27,28]. Multi-gene editing tools are mainly used to construct multiple gene delivery systems to deliver multiple sgRNAs for the treatment of HIV, retrovirus, lentivirus, and HBV [24,[29][30][31]. Here, we constructed a one-vector CRISPR/Cas9 system that can not only screen and identify the key genes of BmNPV systemic infection process, but also verify the antiviral efficiency of multi-gene BmNPV infection process using a multiplex CRISPR/Cas9 system ( Figure 4).…”