Suboptimal splice sites of equine infectious anaemia virus control Rev responsiveness

Microbiology ◽  
2000 ◽  
Vol 81 (5) ◽  
pp. 1265-1272 ◽  
Author(s):  
Rina Rosin-Arbesfeld ◽  
Abraham Yaniv ◽  
Arnona Gazit
Keyword(s):  
Nuclear Export ◽  
Rna Secondary Structure ◽  
Viral Proteins ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Splice Sites ◽  
Responsive Element ◽  
In Cis ◽  
Equine Infectious Anaemia Virus ◽  
Rev Protein

The Rev protein of equine infectious anaemia virus (EIAV) was shown previously to stimulate the expression of a heterologous CAT reporter gene when the 3′ half of the EIAV genome was present downstream in cis. However, computer analysis could not reveal the existence of a stable RNA secondary structure that could be analogous to the Rev-responsive element of other lentiviruses. In the present study, the inhibitory RNA element designated the cis-acting repressing sequence (CRS) has been localized to the centre of the EIAV genome. The inhibition exerted by this element could be overcome by supplying Rev in trans. The ability of the EIAV CRS to function in a heterologous context suggests that it does not require interactions with other viral proteins. Site-directed mutagenesis showed that the various centrally located suboptimal splice sites of the EIAV genome function as CRS and confer Rev-dependence on the CRS-containing transcripts. In addition, the data suggest that in canine Cf2Th cells, which are highly permissive for EIAV replication, CRS prevents nuclear export of CRS-containing transcripts and the supply of Rev relieves this suppression.

scholarly journals The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
David S Booth ◽  
Yifan Cheng ◽  
Alan D Frankel
Keyword(s):  
Binding Sites ◽  
Nuclear Export ◽  
Viral Proteins ◽  
Host Gene Expression ◽  
Rev Response Element ◽  
Hiv Rna ◽  
Binding Surface ◽  
Cellular Tropism ◽  
Hiv Inhibitor ◽  
Rev Protein

The HIV Rev protein routes viral RNAs containing the Rev Response Element (RRE) through the Crm1 nuclear export pathway to the cytoplasm where viral proteins are expressed and genomic RNA is delivered to assembling virions. The RRE assembles a Rev oligomer that displays nuclear export sequences (NESs) for recognition by the Crm1-RanGTP nuclear receptor complex. Here we provide the first view of an assembled HIV-host nuclear export complex using single-particle electron microscopy. Unexpectedly, Crm1 forms a dimer with an extensive interface that enhances association with Rev-RRE and poises NES binding sites to interact with a Rev oligomer. The interface between Crm1 monomers explains differences between Crm1 orthologs that alter nuclear export and determine cellular tropism for viral replication. The arrangement of the export complex identifies a novel binding surface to possibly target an HIV inhibitor and may point to a broader role for Crm1 dimerization in regulating host gene expression.

scholarly journals Protein S-Nitrosylation of Human Cytomegalovirus pp71 Inhibits Its Ability To Limit STING Antiviral Responses

2020 ◽  
Vol 94 (17) ◽  
Author(s):  
Masatoshi Nukui ◽  
Kathryn L. Roche ◽  
Jie Jia ◽  
Paul L. Fox ◽  
Eain A. Murphy
Keyword(s):  
Viral Replication ◽  
Posttranslational Modification ◽  
Protein S ◽  
Viral Proteins ◽  
Antiviral Response ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Antiviral Responses ◽  
Host Antiviral Response ◽  
Efficient Viral Replication

ABSTRACT Human Cytomegalovirus (HCMV) is a ubiquitous pathogen that has coevolved with its host and, in doing so, is highly efficient in undermining antiviral responses that limit successful infections. As a result, HCMV infections are highly problematic in individuals with weakened or underdeveloped immune systems, including transplant recipients and newborns. Understanding how HCMV controls the microenvironment of an infected cell so as to favor productive replication is of critical importance. To this end, we took an unbiased proteomics approach to identify the highly reversible, stress-induced, posttranslational modification (PTM) protein S-nitrosylation on viral proteins to determine the biological impact on viral replication. We identified protein S-nitrosylation of 13 viral proteins during infection of highly permissive fibroblasts. One of these proteins, pp71, is critical for efficient viral replication, as it undermines host antiviral responses, including stimulator of interferon genes (STING) activation. By exploiting site-directed mutagenesis of the specific amino acids we identified in pp71 as protein S-nitrosylated, we found this pp71 PTM diminishes its ability to undermine antiviral responses induced by the STING pathway. Our results suggest a model in which protein S-nitrosylation may function as a host response to viral infection that limits viral spread. IMPORTANCE In order for a pathogen to establish a successful infection, it must undermine the host cell responses inhibitory to the pathogen. As such, herpesviruses encode multiple viral proteins that antagonize each host antiviral response, thereby allowing for efficient viral replication. Human Cytomegalovirus encodes several factors that limit host countermeasures to infection, including pp71. Herein, we identified a previously unreported posttranslational modification of pp71, protein S-nitrosylation. Using site-directed mutagenesis, we mutated the specific sites of this modification thereby blocking this pp71 posttranslational modification. In contexts where pp71 is not protein S-nitrosylated, host antiviral response was inhibited. The net result of this posttranslational modification is to render a viral protein with diminished abilities to block host responses to infection. This novel work supports a model in which protein S-nitrosylation may be an additional mechanism in which a cell inhibits a pathogen during the course of infection.

scholarly journals Protein S-nitrosylation of Human Cytomegalovirus pp71 inhibits its ability to limit STING antiviral responses

2020 ◽  
Author(s):  
Masatoshi Nukui ◽  
Kathryn L. Roche ◽  
Jie Jia ◽  
Paul L. Fox ◽  
Eain A. Murphy
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Protein S ◽  
Viral Proteins ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Post Translational Modification ◽  
Antiviral Responses ◽  
Host Antiviral Response ◽  
Efficient Viral Replication

ABSTRACTHuman Cytomegalovirus (HCMV) is a ubiquitous pathogen that has co-evolved with its host and in doing so, is highly efficient in undermining antiviral responses that limit successful infections. As a result, HCMV infections are highly problematic in individuals with weakened or underdeveloped immune systems including transplant recipients and newborns. Understanding how HCMV controls the microenvironment of an infected cell so as to favor productive replication is of critical importance. To this end, we took an unbiased proteomics approach to identify the highly reversible, stress induced, post-translational modification (PTM), protein S-nitrosylation, on viral proteins to determine the biological impact on viral replication.We identified protein S-nitrosylation of 13 viral proteins during infection of highly permissive fibroblasts. One of these proteins, pp71, is critical for efficient viral replication, as it undermines host antiviral responses, including STING activation. By exploiting site-directed mutagenesis of the specific amino acids we identified in pp71 as protein S-nitrosylated, we found this pp71 PTM diminishes its ability to undermine antiviral responses induced by the STING pathway. Our results suggest a model in which protein S-nitrosylation may function as a host response to viral infection that limits viral spread.IMPORTANCEIn order for a pathogen to establish a successful infection, it must undermine the host cell responses inhibitory to the pathogen. As such, herpesviruses encode multiple viral proteins that antagonize each host antiviral response, thereby allowing for efficient viral replication. Human Cytomegalovirus encodes several factors that limit host countermeasures to infection, including pp71. We identified a previously unreported modification of pp71 residues within the protein are protein S-nitrosylated. Using site-directed mutagenesis, we mutated the specific sites of this modification thereby blocking this pp71 post-translational modification. In contexts where pp71 is not protein S-nitrosylated, host antiviral response was inhibited. The net result of this post-translational modification is to render a viral protein with diminished abilities to block host responses to infection. This novel work supports a model in which protein S-nitrosylation may be an additional mechanism in which a cell inhibits a pathogen during the course of infection.

The site-directed mutagenesis and prokaryotic expression of midkine gene in Cynoglossus semilaevis

2013 ◽  
Vol 37 (3) ◽  
pp. 330
Author(s):  
Yanan WANG ◽  
Xudong LIU ◽  
Linlin MU ◽  
Zhipeng LIU ◽  
Chunmei LI ◽  
...  
Keyword(s):  
Prokaryotic Expression ◽  
Cynoglossus Semilaevis ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis
Sign in / Sign up

Export Citation Format

Share Document