scholarly journals Evidence for a long-r ange RNA-RNA interaction between ORF8 and the downstream region of the Spike polybasic insertion of SARS-CoV-2

2021 ◽  
Author(s):  
Amirhossein Manzourolajdad ◽  
Filipe Pereira

SARS-CoV-2 has affected people all over the world as the causative agent of COVID-19. The virus is related to the highly lethal SARS-CoV responsible for the 2002-2003 SARS outbreak in Asia. Intense research is ongoing to understand why both viruses have different spreading capacities and mortality rates. Similar to other betacoronaviruses, long-range RNA-RNA interactions occur between different parts of the viral genomic RNA, resulting in discontinuous transcription and production of various sub-genomic RNAs. These sub-genomic RNAs are then translated into different viral proteins. An important difference between both viruses is a polybasic insertion in the Spike region of SARS-CoV-2, absent in SARS-CoV. Here we show that a 26-base-pair long-range RNA-RNA interaction occurs between the genomic region downstream of the Spike insertion and ORF8 in SARS-CoV-2. Predictions suggest that the corresponding ORF8 region forms the most energetically favorable interaction with that of Spike region from amongst all possible candidate regions within SARS-CoV-2 genomic RNA. We also found signs of sequence covariation in the predicted interaction using a large dataset with 27,592 full-length SARS-CoV-2 genomes. In particular, a synonymous mutation in ORF8 accommodated for base pairing with Spike [G23675 C28045U], and a non-synonymous mutation in Spike accommodated for base pairing with ORF8 [C23679U G28042] both of which were in close proximity of one another. The predicted interactions can potentially be related to regulation of sub-genomic RNA production rates.

Author(s):  
Omer Ziv ◽  
Jonathan Price ◽  
Lyudmila Shalamova ◽  
Tsveta Kamenova ◽  
Ian Goodfellow ◽  
...  

SUMMARYThe Coronaviridae is a family of positive-strand RNA viruses that includes SARS-CoV-2, the etiologic agent of the COVID-19 pandemic. Bearing the largest single-stranded RNA genomes in nature, coronaviruses are critically dependent on long-distance RNA-RNA interactions to regulate the viral transcription and replication pathways. Here we experimentally mapped the in vivo RNA-RNA interactome of the full-length SARS-CoV-2 genome and subgenomic mRNAs. We uncovered a network of RNA-RNA interactions spanning tens of thousands of nucleotides. These interactions reveal that the viral genome and subgenomes adopt alternative topologies inside cells, and engage in different interactions with host RNAs. Notably, we discovered a long-range RNA-RNA interaction - the FSE-arch - that encircles the programmed ribosomal frameshifting element. The FSE-arch is conserved in the related MERS-CoV and is under purifying selection. Our findings illuminate RNA structure based mechanisms governing replication, discontinuous transcription, and translation of coronaviruses, and will aid future efforts to develop antiviral strategies.


2004 ◽  
Vol 78 (20) ◽  
pp. 10927-10938 ◽  
Author(s):  
Catherine S. Hibbert ◽  
Jane Mirro ◽  
Alan Rein

ABSTRACT Prior work by others has shown that insertion of ψ (i.e., leader) sequences from the Moloney murine leukemia virus (MLV) genome into the 3′ untranslated region of a nonviral mRNA leads to the specific encapsidation of this RNA in MLV particles. We now report that these RNAs are, like genomic RNAs, encapsidated as dimers. These dimers have the same thermostability as MLV genomic RNA dimers; like them, these dimers are more stable if isolated from mature virions than from immature virions. We characterized encapsidated mRNAs containing deletions or truncations of MLV ψ or with ψ sequences from MLV-related acute transforming viruses. The results indicate that the dimeric linkage in genomic RNA can be completely attributed to the ψ region of the genome. While this conclusion agrees with earlier electron microscopic studies on mature MLV dimers, it is the first evidence as to the site of the linkage in immature dimers for any retrovirus. Since the Ψ+ mRNA is not encapsidated as well as genomic RNA, it is only present in a minority of virions. The fact that it is nevertheless dimeric argues strongly that two of these molecules are packaged into particles together. We also found that the kissing loop is unnecessary for this coencapsidation or for the stability of mature dimers but makes a major contribution to the stability of immature dimers. Our results are consistent with the hypothesis that the packaging signal involves a dimeric structure in which the RNAs are joined by intermolecular interactions between GACG loops.


1995 ◽  
Vol 15 (5) ◽  
pp. 2367-2373 ◽  
Author(s):  
N Armes ◽  
M Fried

The Surf-3 gene of the unusually tight mouse Surfeit locus gene cluster has been identified as the highly conserved ribosomal protein gene L7a (rpL7a). The topography and juxtaposition of the Surfeit locus genes are conserved for the 600 million years of divergent evolution between mammals and birds. This suggests cis interaction and/or coregulation of the genes and suggests that, within this locus, gene organization plays an important role in gene expression. The further evolutionary conservation of the organization of the Surfeit locus was investigated. A cDNA encoding the Drosophila melanogaster homolog of the Surf-3/rpL7a gene was cloned, was shown to be present as a single copy, and was expressed constitutively at high levels throughout development. Genomic cosmid clones encompassing the gene and its surrounding DNA were isolated. The gene was determined to have five introns, of which two were located in the 5' untranslated region of the gene. The remaining three introns had splice sites at positions equivalent to those found in the Surf-3/rpL7a mammalian homologs. S1 analysis and 5' rapid amplification of cDNA ends both confirmed the start of transcription to occur in a polypyrimidine tract in the absence of a TATA box in the promoter. The genomic region around the Surf-3/rpL7a gene was analyzed by low-stringency hybridization with murine Surfeit gene probes, by partial sequence analysis, and by hybridization of fragments to Northern (RNA) blots. No homologs of other members of the Surfeit gene cluster were detected in close proximity to the D. melanogaster Surf-3/rpL7a gene. However, a gene which was detected directly 3' to the Surf-3/rpL7a gene was shown to encode a homolog of a mammalian serine-pyruvate aminotransferase.


1995 ◽  
Vol 15 (1) ◽  
pp. 235-245 ◽  
Author(s):  
W Scheper ◽  
D Meinsma ◽  
P E Holthuizen ◽  
J S Sussenbach

Human insulin-like growth factor II (IGF-II) mRNAs are subject to site-specific endonucleolytic cleavage in the 3' untranslated region, leading to an unstable 5' cleavage product containing the IGF-II coding region and a very stable 3' cleavage product of 1.8 kb. This endonucleolytic cleavage is most probably the first and rate-limiting step in degradation of IGF-II mRNAs. Two sequence elements within the 3' untranslated region are required for cleavage: element I, located approximately 2 kb upstream of the cleavage site, and element II, encompassing the cleavage site itself. We have identified a stable double-stranded RNA stem structure (delta G = -100 kcal/mol [418.4 kJ/mol]) that can be formed between element I and a region downstream of the cleavage site in element II. This structure is conserved among human, rat, and mouse mRNAs. Detailed analysis of the requirements for cleavage shows that the relative position of the elements is not essential for cleavage. Furthermore, the distance between the coding region and the cleavage site does not affect the cleavage reaction. Mutational analysis of the long-range RNA-RNA interaction shows that not only the double-stranded character but also the sequence of the stable RNA stem is important for cleavage.


1993 ◽  
Vol 21 (8) ◽  
pp. 1713-1717 ◽  
Author(s):  
J. van Himbergen ◽  
B. van Geffen ◽  
J. van Duin

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1459
Author(s):  
Xiaonan Ma ◽  
Zhenghe Li

Generation of recombinant negative-stranded RNA viruses (NSVs) from plasmids involves in vivo reconstitution of biologically active nucleocapsids and faces a unique antisense problem where the negative-sense viral genomic RNAs can hybridize to viral messenger RNAs. To overcome this problem, a positive-sense RNA approach has been devised through expression of viral antigenomic (ag)RNA and core proteins for assembly of antigenomic nucleocapsids. Although this detour strategy works for many NSVs, the process is still inefficient. Using Sonchus yellow net rhabdovirus (SYNV) as a model; here, we develop a negative-sense genomic RNA-based approach that increased rescue efficiency by two orders of magnitude compared to the conventional agRNA approach. The system relied on suppression of double-stranded RNA induced antiviral responses by co-expression of plant viruses-encoded RNA silencing suppressors or animal viruses-encoded double-stranded RNA antagonists. With the improved approach, we were able to recover a highly attenuated SYNV mutant with a deletion in the matrix protein gene which otherwise could not be rescued via the agRNA approach. Reverse genetics analyses of the generated mutant virus provided insights into SYNV virion assembly and morphogenesis. This approach may potentially be applicable to other NSVs of plants or animals.


mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Yukiyo Sato ◽  
Wajeeha Shamsi ◽  
Atif Jamal ◽  
Muhammad Faraz Bhatti ◽  
Hideki Kondo ◽  
...  

ABSTRACT The search for viruses infecting fungi, or mycoviruses, has extended our knowledge about the diversity of RNA viruses, as exemplified by the discovery of polymycoviruses, a phylogenetic group of multisegmented RNA viruses with unusual forms. The genomic RNAs of known polymycoviruses, which show a phylogenetic affinity for animal positive-sense single-stranded RNA [(+)RNA] viruses such as caliciviruses, are comprised of four conserved segments with an additional zero to four segments. The double-stranded form of polymycovirus genomic RNA is assumed to be associated with a virally encoded protein (proline-alanine-serine-rich protein [PASrp]) in either of two manners: a capsidless colloidal form or a filamentous encapsidated form. Detailed molecular characterizations of polymycoviruses, however, have been conducted for only a few strains. Here, a novel polymyco-related virus named Hadaka virus 1 (HadV1), from the phytopathogenic fungus Fusarium oxysporum, was characterized. The genomic RNA of HadV1 consisted of an 11-segmented positive-sense RNA with highly conserved terminal nucleotide sequences. HadV1 shared the three conserved segments with known polymycoviruses but lacked the PASrp-encoding segment. Unlike the known polymycoviruses and encapsidated viruses, HadV1 was not pelleted by conventional ultracentrifugation, possibly due to the lack of PASrp. This result implied that HadV1 exists only as a soluble form with naked RNA. Nevertheless, the 11 genomic segments of HadV1 have been stably maintained through host subculturing and conidiation. Taken together, the results of this study revealed a virus with a potential novel virus lifestyle, carrying many genomic segments without typical capsids or PASrp-associated forms. IMPORTANCE Fungi collectively host various RNA viruses. Examples include encapsidated double-stranded RNA (dsRNA) viruses with diverse numbers of genomic segments (from 1 to 12) and capsidless viruses with nonsegmented (+)RNA genomes. Recently, viruses with unusual intermediate features of an infectious entity between encapsidated dsRNA viruses and capsidless (+)RNA viruses were found. They are called polymycoviruses, which typically have four to eight dsRNA genomic segments associated with one of the virus-encoded proteins and are phylogenetically distantly related to animal (+)RNA caliciviruses. Here, we identified a novel virus phylogenetically related to polymycoviruses, from the phytopathogenic fungus Fusarium oxysporum. The virus, termed Hadaka virus 1 (HadV1), has 11 (+)RNA genomic segments, the largest number in known (+)RNA viruses. Nevertheless, HadV1 lacked a typical structural protein of polymycoviruses and was not pelleted by standard ultracentrifugation, implying an unusual capsidless nature of HadV1. This study reveals a potential novel lifestyle of multisegmented RNA viruses.


2005 ◽  
Vol 168 (5) ◽  
pp. 691-696 ◽  
Author(s):  
Etsuko Muto ◽  
Hiroyuki Sakai ◽  
Kuniyoshi Kaseda

Interaction of kinesin-coated latex beads with a single microtubule (MT) was directly observed by fluorescence microscopy. In the presence of ATP, binding of a kinesin bead to the MT facilitated the subsequent binding of other kinesin beads to an adjacent region on the MT that extended for micrometers in length. This cooperative binding was not observed in the presence of ADP or 5′-adenylylimidodiphosphate (AMP-PNP), where binding along the MT was random. Cooperative binding also was induced by an engineered, heterodimeric kinesin, WT/E236A, that could hydrolyze ATP, yet remained fixed on the MT in the presence of ATP. Relative to the stationary WT/E236A kinesin on a MT, wild-type kinesin bound preferentially in close proximity, but was biased to the plus-end direction. These results suggest that kinesin binding and ATP hydrolysis may cause a long-range state transition in the MT, increasing its affinity for kinesin toward its plus end. Thus, our study highlights the active involvement of MTs in kinesin motility.


2011 ◽  
Vol 92 (5) ◽  
pp. 1199-1204 ◽  
Author(s):  
Hao Wang ◽  
Antti Vaheri ◽  
Friedemann Weber ◽  
Alexander Plyusnin

dsRNA and 5′-triphosphate RNA are considered critical activators of the innate immune response because of their interaction with pattern recognition receptors. It has been reported that no dsRNA is detected in negative-sense RNA virus-infected cells and that Hantaan virus (HTNV) genomic RNA bears a 5′ monophosphate group. In this paper we examine the 5′ termini of genomic RNAs of and dsRNA production by two major groups of Old World hantaviruses. No detectable amounts of dsRNA were found in infected cells. Also, the genomic RNAs of these hantaviruses bear a 5′ monophosphate group and therefore are unable to trigger interferon induction. Taken together with the earlier data on HTNV, these results suggest that in addition to the dsRNA and genomic RNA, which may be only minimally involved in the induction of innate immunity, other cellular signalling pathways may also be involved and that these await further investigation.


Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 195 ◽  
Author(s):  
Joji Otaki

Butterfly eyespot color patterns have been studied using several different approaches, including applications of physical damage to the forewing. Here, damage and distortion experiments were performed, focusing on the hindwing eyespots of the blue pansy butterfly Junonia orithya. Physical puncture damage with a needle at the center of the eyespot reduced the eyespot size. Damage at the eyespot outer rings not only deformed the entire eyespot, but also diminished the eyespot core disk size, despite the distance from the damage site to the core disk. When damage was inflicted near the eyespot, the eyespot was drawn toward the damage site. The induction of an ectopic eyespot-like structure and its fusion with the innate eyespots were observed when damage was inflicted in the background area. When a small stainless ball was placed in close proximity to the eyespot using the forewing-lift method, the eyespot deformed toward the ball. Taken together, physical damage and distortion elicited long-range inhibitory, drawing (attracting), and inducing effects, suggesting that the innate and induced morphogenic signals travel long distances and interact with each other. These results are consistent with the distortion hypothesis, positing that physical distortions of wing tissue contribute to color pattern determination in butterfly wings.


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