scholarly journals A new Dicistrovirus from soldier fly Inopus flavus (James) (Diptera: Stratiomyidae), a pest of sugarcane

2020 ◽  
Author(s):  
Angelique K. Asselin ◽  
Kayvan Etabari ◽  
Michael J. Furlong ◽  
Karyn N. Johnson

AbstractThe native Australian soldier flies, Inopus spp. (Diptera: Stratiomyidae), are agricultural pests of economic importance to the sugarcane industry. While adult soldier flies do not feed on sugarcane, larvae spend one to two-years underground feeding on roots, causing mechanical and systemic damage to crops (Saccharum officinarum L.) that impacts yield. Current measures of pest control commonly target above ground pests and are ineffective against solider fly larvae, highlighting the importance of novel control methods. A screen of the salivary gland transcriptome of Inopus flavus (James) revealed the presence of viral RNA belonging to a potentially novel member of the Dicistroviridae family. Viruses from this family have been found naturally infecting insects from a range of taxonomic groups and they often cause pathogenesis in their hosts. To characterise the genetic and physical properties of the new virus, the positive RNA genome was analysed using a combination of sequencing approaches. The virus genome is organised similarly to members of the Dicistroviridae with two open reading frames (ORF) the first encoding non-structural proteins and the second encoding structural proteins. The genome includes two potential internal ribosomal entry sites (IRES) one within the 5’ UTR and the other in the intergenic region (IGR). Based on the amino acid sequences of the non-structural and structural polyproteins encoded by the two ORF soldier fly virus groups within the dicistrovirus family. Virus particles purified from infected larvae and visualised by electron microscopy are icosahedral, non-enveloped, and 30 nm in diameter. The genetic and physical characteristics of this novel soldier fly virus are consistent with it being a member of the Dicistroviridae.

2000 ◽  
Vol 20 (14) ◽  
pp. 4990-4999 ◽  
Author(s):  
Joan E. Wilson ◽  
Marguerite J. Powell ◽  
Susan E. Hoover ◽  
Peter Sarnow

ABSTRACT Cricket paralysis virus is a member of a group of insect picorna-like viruses. Cloning and sequencing of the single plus-strand RNA genome revealed the presence of two nonoverlapping open reading frames, ORF1 and ORF2, that encode the nonstructural and structural proteins, respectively. We show that each ORF is preceded by one internal ribosome entry site (IRES). The intergenic IRES is located 6,024 nucleotides from the 5′ end of the viral RNA and is more active than the IRES located at the 5′ end of the RNA, providing a mechanistic explanation for the increased abundance of structural proteins relative to nonstructural proteins in infected cells. Mutational analysis of this intergenic-region IRES revealed that ORF2 begins with a noncognate CCU triplet. Complementarity of this CCU triplet with sequences in the IRES is important for IRES function, pointing to an involvement of RNA-RNA interactions in translation initiation. Thus, the cricket paralysis virus genome is an example of a naturally occurring, functionally dicistronic eukaryotic mRNA whose translation is controlled by two IRES elements located at the 5′ end and in the middle of the mRNA. This finding argues that eukaryotic mRNAs can express multiple proteins not only by polyprotein processing, reinitiation and frameshifting but also by using multiple IRES elements.


2002 ◽  
Vol 83 (12) ◽  
pp. 3075-3084 ◽  
Author(s):  
Afjal Hossain Khan ◽  
Kouichi Morita ◽  
Maria del Carmen Parquet ◽  
Futoshi Hasebe ◽  
Edward G. M. Mathenge ◽  
...  

In this study, the complete genomic sequence of chikungunya virus (CHIK; S27 African prototype) was determined and the presence of an internal polyadenylation [I-poly(A)] site was confirmed within the 3′ non-translated region (NTR) of this strain. The complete genome was 11805 nucleotides in length, excluding the 5′ cap nucleotide, an I-poly(A) tract and the 3′ poly(A) tail. It comprised two long open reading frames that encoded the non-structural (2474 amino acids) and structural polyproteins (1244 amino acids). The genetic location of the non-structural and structural proteins was predicted by comparing the deduced amino acid sequences with the known cleavage sites of other alphaviruses, located at the C-terminal region of their virus-encoded proteins. In addition, predicted secondary structures were identified within the 5′ NTR and repeated sequence elements (RSEs) within the 3′ NTR. Amino acid sequence homologies, phylogenetic analysis of non-structural and structural proteins and characteristic RSEs revealed that although CHIK is closely related to o’nyong-nyong virus, it is in fact a distinct virus. The existence of I-poly(A) fragments with different lengths (e.g. 19, 36, 43, 91, 94 and 106 adenine nucleotides) at identical initiation positions for each clone strongly suggests that the polymerase of the alphaviruses has a capacity to create poly(A) by a template-dependant mechanism such as ‘polymerase slippage’, as has been reported for vesicular stomatitis virus.


Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Brad L. Ericson ◽  
Darby J. Carlson ◽  
Kimberly A. Carlson

Nora virus is a single stranded RNA picorna-like virus with four open reading frames (ORFs). The coding potentials of the ORFs are not fully characterized, but ORF3 and ORF4 are believed to encode the capsid proteins (VP3, VP4a, VP4b, and VP4c) comprising the virion. To determine the polypeptide composition of Nora virus virions, polypeptides from purified virus were compared to polypeptides detected in Nora virus infectedDrosophila melanogaster. Nora virus was purified from infected flies and used to challenge mice for the production of antisera.ORF3,ORF4a,ORF4b, andORF4cwere individually cloned and expressed inE. coli; resultant recombinant proteins purified and were used to make monospecific antisera. Antisera were evaluated via Western blot against whole virus particles and Nora virus infected fly lysates. Viral purification yielded two particle types with densities of ~1.31 g/mL (empty particles) and ~1.33 g/mL (complete virions). Comparison of purified virus polypeptide composition to Nora virus infectedD. melanogasterlysate showed the number of proteins in infected cell lysates is less than purified virus. Our results suggest the virion is composed of 6 polypeptides, VP3, VP4a, two forms of VP4b, and two forms of VP4c. This polypeptide composition is similar to other small RNA insect viruses.


2017 ◽  
Vol 61 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Ning Jia ◽  
Yunwen Ou ◽  
Zygmunt Pejsak ◽  
Yongguang Zhang ◽  
Jie Zhang

AbstractAfrican swine fever virus (ASFV) is a large, double-stranded DNA virus and the sole member of the Asfarviridae family. ASFV infects domestic pigs, wild boars, warthogs, and bush pigs, as well as soft ticks (Ornithodoros erraticus), which likely act as a vector. The major target is swine monocyte-macrophage cells. The virus can cause high fever, haemorrhagic lesions, cyanosis, anorexia, and even fatalities in domestic pigs. Currently, there is no vaccine and effective disease control strategies against its spread are culling infected pigs and maintaining high biosecurity standards. African swine fever (ASF) spread to Europe from Africa in the middle of the 20th century, and later also to South America and the Caribbean. Since then, ASF has spread more widely and thus is still a great challenge for swine breeding. The genome of ASFV ranges in length from about 170 to 193 kbp depending on the isolate and contains between 150 and 167 open reading frames (ORFs). The ASFV genome encodes 150 to 200 proteins, around 50 of them structural. The roles of virus structural proteins in viral infection have been described. These proteins, such as pp220, pp62, p72, p54, p30, and CD2v, serve as the major component of virus particles and have roles in attachment, entry, and replication. All studies on ASFV proteins lay a good foundation upon which to clarify the infection mechanism and develop vaccines and diagnosis methods. In this paper, the roles of ASFV structural proteins in viral infection are reviewed.


2002 ◽  
Vol 83 (11) ◽  
pp. 2869-2877 ◽  
Author(s):  
F. van der Wilk ◽  
A. M. Dullemans ◽  
M. Verbeek ◽  
J. F. J. M. van den Heuvel

The complete nucleotide sequence of an ophiovirus associated with lettuce big-vein disease has been elucidated. The genome consisted of four RNA molecules of approximately 7·8, 1·7, 1·5 and 1·4 kb. Virus particles were shown to contain nearly equimolar amounts of RNA molecules of both polarities. The 5′- and 3′-terminal ends of the RNA molecules are largely, but not perfectly, complementary to each other. The virus genome contains seven open reading frames. Database searches with the putative viral products revealed homologies with the RNA-dependent RNA polymerases of rhabdoviruses and Ranunculus white mottle virus, and the capsid protein of Citrus psorosis virus. The gene encoding the viral polymerase appears to be located on the RNA segment 1, while the nucleocapsid protein is encoded by the RNA3. No significant sequence similarities were observed with other viral proteins. In spite of the morphological resemblance with species in the genus Tenuivirus, the ophioviruses appear not to be evolutionary closely related to this genus nor any other viral genus.


Author(s):  
A.D. Hyatt

Bluetongue virus (BTV) is the type species os the genus orbivirus in the family Reoviridae. The virus has a fibrillar outer coat containing two major structural proteins VP2 and VP5 which surround an icosahedral core. The core contains two major proteins VP3 and VP7 and three minor proteins VP1, VP4 and VP6. Recent evidence has indicated that the core comprises a neucleoprotein center which is surrounded by two protein layers; VP7, a major constituent of capsomeres comprises the outer and VP3 the inner layer of the core . Antibodies to VP7 are currently used in enzyme-linked immunosorbant assays and immuno-electron microscopical (JEM) tests for the detection of BTV. The tests involve the antibody recognition of VP7 on virus particles. In an attempt to understand how complete viruses can interact with antibodies to VP7 various antibody types and methodologies were utilized to determine the physical accessibility of the core to the external environment.


1998 ◽  
Vol 11 (4) ◽  
pp. 614-627 ◽  
Author(s):  
A. K. Patick ◽  
K. E. Potts

SUMMARY Currently, there are a number of approved antiviral agents for use in the treatment of viral infections. However, many instances exist in which the use of a second antiviral agent would be beneficial because it would allow the option of either an alternative or a combination therapeutic approach. Accordingly, virus-encoded proteases have emerged as new targets for antiviral intervention. Molecular studies have indicated that viral proteases play a critical role in the life cycle of many viruses by effecting the cleavage of high-molecular-weight viral polyprotein precursors to yield functional products or by catalyzing the processing of the structural proteins necessary for assembly and morphogenesis of virus particles. This review summarizes some of the important general features of virus-encoded proteases and highlights new advances and/or specific challenges that are associated with the research and development of viral protease inhibitors. Specifically, the viral proteases encoded by the herpesvirus, retrovirus, hepatitis C virus, and human rhinovirus families are discussed.


Vaccine ◽  
2006 ◽  
Vol 24 (44-46) ◽  
pp. 6647-6650 ◽  
Author(s):  
Emmie de Wit ◽  
Monique I.J. Spronken ◽  
Guus F. Rimmelzwaan ◽  
Albert D.M.E. Osterhaus ◽  
Ron A.M. Fouchier

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Daniela Lepka ◽  
Tobias Kerrinnes ◽  
Evelyn Skiebe ◽  
Birgitt Hahn ◽  
Angelika Fruth ◽  
...  

We report the nucleotide sequence of two novel cryptic plasmids (4357 and 14 662 base pairs) carried by aYersinia enterocoliticabiotype 1A strain isolated from pork. As distinguished from most biotype 1A strains, this isolate, designated 07-04449, exhibited adherence to eukaryotic cells. The smaller plasmid pYe4449-1 carries five attributable open reading frames (ORFs) encoding the first CcdA/CcdB-like antitoxin/toxin system described for aYersiniaplasmid, a RepA-like replication initiation protein, and mobilizing factors MobA and MobC. The deduced amino acid sequences showed highest similarity to proteins described inSalmonella(CcdA/B),Klebsiella(RepA), andPlesiomonas(MobA/C) indicating genomic fluidity among members of theEnterobacteriaceae. One additional ORF with unknown function, termed ORF5, was identified with an ancestry distinct from the rest of the plasmid. While the C+G content of ORF5 is 38.3%, the rest of pYe4449-1 shows a C+G content of 55.7%. The C+G content of the larger plasmid pYe4449-2 (54.9%) was similar to that of pYe4449-1 (53.7%) and differed from that of theY. enterocoliticagenome (47.3%). Of the 14 ORFs identified on pYe4449-2, only six ORFs showed significant similarity to database entries. For three of these ORFs likely functions could be ascribed: a TnpR-like resolvase and a phage replication protein, localized each on a low C+G island, and DNA primase TraC. Two ORFs of pYe4449-2, ORF3 and ORF7, seem to encode secretable proteins. Epitope-tagging of ORF3 revealed protein expression at4°Cbut not at or above27°Csuggesting adaptation to a habitat outside swine. The hypothetical protein encoded by ORF7 is the member of a novel repeat protein family sharing theDxxGN(x)nDxxGNmotif. Our findings illustrate the exceptional gene pool diversity within the speciesY. enterocoliticadriven by horizontal gene transfer events.


2003 ◽  
Vol 84 (12) ◽  
pp. 3459-3464 ◽  
Author(s):  
Livia Stavolone ◽  
Antonio Ragozzino ◽  
Thomas Hohn

Cestrum yellow leaf curling virus (CmYLCV) has been characterized as the aetiological agent of the Cestrum parqui mosaic disease. The virus genome was cloned and the clone was proven to be infectious to C. parqui. The presence of typical viroplasms in virus-infected plant tissue and the information obtained from the complete genomic sequence confirmed CmYLCV as a member of the Caulimoviridae family. All characteristic domains conserved in plant pararetroviruses were found in CmYLCV. Its genome is 8253 bp long and contains seven open reading frames (ORFs). Phylogenetic analysis of the relationships with other members of the Caulimoviridae revealed that CmYLCV is closely related to the Soybean chlorotic mottle virus (SbCMV)-like genus and particularly to SbCMV. However, in contrast to the other members of this genus, the primer-binding site is located in the intercistronic region following ORF Ib rather than within this ORF, and an ORF corresponding to ORF VII is missing.


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