Genome organization an overview sciencedirect topics. Bunyaviridae have tripartite genomes consisting of a large l, medium m, and small s rna segment. N proteins oligomerize and bind to both genome rna and crna. The lateral organization of the spikes has been postulated to be icosahedrally symmetric, with hexameric and pentameric clusters creating a specific socalled t 12 arrangement, but the exact organization and structure of the spikes have remained obscure. Bunyaviridae genome structure and gene expression springerlink. Aug 23, 2018 the specificity of the lentivirus genus is that it contains a diploid single stranded positive sense rna genome, i. Comparison with other viral sequences revealed that stbv has unique sequences in the terminal regions that are highly conserved among the genus orthonairovirus. Because of this, the rnas form noncovalently closed circles.
This genus includes the west nile virus, dengue virus, tickborne encephalitis virus, yellow fever virus, zika virus and several other viruses which may cause encephalitis, as well as insectspecific flaviviruses isfs such as cell fusing agent virus cfav, palm creek virus pcv, and parramatta river virus parv. The structure of each of the three genomic segments is shown above a reference segment from the related virus, kigv. The term retro means backward and the name retrovirus is derived from the fact that these viruses. A nukv exhibits standard phasmavirus genome organization. Bunyavirales is an order of negativesense singlestranded rna viruses. Golv has a different genome organization than phleboviruses. Genera are distinguished by their genome organization and the translational polarity of the genome segments, which are in either negativesense or a combination of negativesense and ambisense. Mechanistic insight into bunyavirusinduced membrane fusion.
We provide a detailed description for a novel bunyavirus carcinus maenas. The nonstructural ns protein, which is a major virulence factor for rift valley fever virus rvfv, is encoded on the ssegment. Structural insights into bunyavirus replication and its regulation by. The complete nucleotide sequence and genome organization of. The three viral rna segments code for a minimum of four structural proteins in a negativesense orientation figure 1 1. Bunyavirus genome organization and virion structure. Hantavirus, orthobunyavirus, nairovirus, tospovirus, and phlebovirus.
Structure and genome organization of the large rna of iris yellow spot virus genus tospovirus, family bunyaviridae article pdf available in archives of virology 1552. N proteins range in size from 19 kda for orthobunyaviruses to 54 kda for hantaviruses and nairoviruses. Structure and replication request pdf researchgate. Bunyavirus transmission is controlled by restricting the arthropod vector or vertebrate reservoir. The full hiv genome is encoded on one long strand of rna. These arthropodborne viruses belong mainly to the families togaviridae, flaviviridae, and bunyaviridae. No of sequence data on plant virus genome generated over the last one decade 1st viral genome sequenced was dna of camv franck et al. The bunyaviridae family is comprised of a large number of negativesense, singlestranded. However, s and m segment termini are shorter with a length of only 5 instead of 8 nt. Rna encapsidation and packaging in the phleboviruses mdpi.
Genomic characterization of the genus nairovirus family bunyaviridae jens h. Structural insights into bunyavirus replication and its regulation by the vrna promoter piotr gerlach,1,2 3 he. The complete genome sequence of the soft tick bunyavirus stbv was obtained using the sanger sequencing technique. Number of nucleotides of largest segment 630012000 rnal. In general, bunyavirus virion structure constitutes largely uncharted territory because no crystal structure of the two glycoproteinsand no 3d structures of the virions exist for any of. In general, bunyavirus virion structure constitutes. Bunyavirus n proteins are always encoded by the s genome segment. Genome reassortment has been demonstrated to occur in cell cultures infected with certain bunyaviruses of the same serogroup, but to fail with viruses from different serogroups, even when they. Sequence analysis indicated a classical orthobunyaviral genome organization for the studied isolates sw27571, k190, 12005, k42904 and k10441, coding the n protein by the ssegment, the gnnsmgc glycoprotein precursor polyprotein by the msegment, and the viral characterization and phylogeny of australian bunyaviruses. Each segment has a similar organization, with short untranslated regions utrs. Terminal genome sequences of the soft tick bunyavirus. The specificity of the lentivirus genus is that it contains a diploid single stranded positive sense rnagenome, i. In a free virus particle, there are actually two separate strands of rna, but theyre exactly the same. Bunyaviruses are spherical, enveloped particles 90 to 100 nm in.
Possible genome segment organization of reported heterotypic reassortant bunyaviruses. Due to the extremely wide 68 host range, tswv has caused severe economic losses to various agricultural, vegetable and. Like other members of the bunyavirus family, hantaviruses are enveloped viruses with a genome that consists of three singlestranded rna segments designated s small, m medium, and l large. Structural differences observed in arboviruses of the. Bunyavirus morphology is somewhat similar to that of the paramyxoviridae family. Serogroup or genus, virus, s segment, m segment, l segment.
Facts of genome molecular wt of nucleotide pair 650 da wt of chromosome varies greatly no. Viruses range from the structurally simple and small parvoviruses and picornaviruses to the large and complex poxviruses and herpesviruses. In general, bunyavirus virion structure constitutes largely uncharted territory. Strategies used in the approach to genome studies are discussed. The genome organization of amv and closely related ilarviruses is similar to that of bmv appendix a, profile 51, but there is an involvement of cp, either from the virus particle or expressed from sgrna4 for replication in a process called genome activation. However, with such a large number of members it is perhaps not unexpected that within the family there is significant diversity in genome structures and expression strategies. This group of viruses contains many pathogens that cause febrile, hemorrhagic, and encephalitic disease or arthritic symptoms which can be persistent. These studies have revealed both similarities ty and remarkable differences in the strategies used for yaua generation of viral proteins. Bunyavirus genome organization and virion structure bunyaviruses are enveloped with a trisegmented singlestranded rna genome, which replicates in the cytosol 1. Structure and replication the bunyaviridae family is comprised of a large number of negativesense, singlestranded rna viruses. Genomic and developmental characterisation of a novel.
Through the cullin 1skp1fbox e3 ligase complex, the nss protein promotes the degradation of at least two host proteins, the tfiih p62 and the pkr proteins. Rna encapsidation and packaging in the phleboviruses. It constitutes 8% of the rye genome, 25% of pea, 40% of snail and 70% of human genome. Viruses are small obligate intracellular parasites, which by definition contain either a rna or dna genome surrounded by a protective, viruscoded protein coat. In contrast to phleboviruses, there is no evidence for encoded nss and nsm proteins. Untranslated regions are shown as filled rectangles and orfs are shown as arrows. Genome sequences of a novel vietnamese bat bunyavirus bas b. Arthropod borne viruses have developed a complex life cycle adapted to alternate between insect and vertebrate hosts. Genome sequences of a novel vietnamese bat bunyavirus. Bunyavirus genomes consist of three rna segments called large, medium, and small l, m, and s. In general, bunyavirus virion structure constitutes largely uncharted territory because no crystal structure of the two glycoproteinsand no 3d structures of the virions exist for any of the 350 members of the family. Circular through hydrogenbonded ends, sometimes supercoiled.
The host rna sequence in some representative viruses primes viral mrna. Rna encapsidation and packaging in the phleboviruses ncbi. A comparison of the deduced amino acid sequence of gp revealed 37% identity and 5859% similarity with that of tomato spotted wilt virus tswv, serogroup i and impatiens necrotic spot virus insv, serogroup iii, and 2123% identity and 4447% similarity with those of other members of the genus bunyavirus. Pdf structure and genome organization of the large rna.
Ellioviricetes is named in honor of late virologist richard m. Bacterial genome is considered to be composed of unique dna. For each segment, transcription, generating capped viral mrnas, and replication, generating fulllength genome or antigenome copies vrna and crna, respectively, are performed by the same virally encoded rna. The tripartite genome of bunyaviruses, encapsidated in the form of individual ribonucleoprotein complexes, encodes four structural proteins, the glycoproteins gc and gn, the nucleoprotein n, and the viral polymerase l. A the genes encoded in the three strands of a typical phlebovirus genome are represented by open boxes labeled with each genes abbreviation and the average size of each strand. More than 300 viruses are included in the family bunyaviridae and hence show a number of unifying characteristics. Insights into bunyavirus architecture from electron. Infection and pathogenesis of huaiyangshan virus a novel. It was formerly known as bunyaviridae family of viruses. Carcinus maenas is in the top 100 globally invasive species and harbours a wide diversity of pathogens, including viruses. This is the form it has when it is a free virus particle. All hantaviral genes are encoded in the negative genome complementary sense. Table 2 and figure 1 both show the breadth of genes that can be encoded.
Each genome segment has the same basic structure with the coding region flanked by. In general, the genome organization is less complex. The structure of the monomeric bunyavirus polymerase reveals that divergent segmented negativestrand. N also interacts with l, gn, and gc proteins to facilitate virion assembly and morphogenesis. Retrovirus is a virus containing rna genome that replicates through a dna intermediate. Bunyaviridae family 1 bunyaviridae family 2 bunyavirus pathogenesis.
The terminal sequences of each segment are basepaired. Infection and pathogenesis of huaiyangshan virus a novel tickborne bunyavirus in laboratory rodents xiaoping chen 1, meili cong 1, minghui li 1, yanjun kang 1, yanmeng feng 1, alexander plyusnin 1,2, jianguo xu 1, yongzhen zhang 1. Rift valley fever virus nss protein functions and the. Analysis of arbovirus isolates from australia identifies. While some viral species such as puumala cause a mild clinical disease, other species can have particularly severe clinical outcomes. The bunyavirus genome is monomeric and consists of three segments of linear negativesense or ambisense, depending on the genus rna. Department of molecular microbiology, washington university school of medicine, box 8230, 660 south euclid avenue, st. Flavivirus is a genus of viruses in the family flaviviridae. Pesticides are used on a communitywide basis, as well as at the breeding sites of arthropods. Bunyavirales form enveloped, spherical virions with diameters of 90100 nm. Personal measures, such as the use of proper protective clothing, repellents, bed nets, and house screens, are effective but are often forgotten.
In balows a, hausler wj jr, herrmann kl, isenberg hd, shadomy hj eds. The bunyaviridae family is comprised of a large number of negativesense, singlestranded rna viruses that infect animals, insects, and plants. Genome organization like other viruses with a segmented genome, the bunyaviridae have the ability to exchange genome segments during mixed infections. Bunyaviruses are enveloped with a trisegmented singlestranded rna genome, which. Using longread sequencing suited to the highly repetitive mosquito genome, they explore the origin of these sequences and. The tripartite genome organization of the bunyaviridae family offers. Sep 10, 2019 carcinus maenas is in the top 100 globally invasive species and harbours a wide diversity of pathogens, including viruses. Pdf structure and genome organization of the large rna of. Travassos da rosa 3, hilda guzman 3, nazir savji 5, jason t.
Akashi h, gay m, ihara t, bishop dhl 1984 localized conserved regions of the s rna gene products of bunyaviruses are revealed by sequence analyses of. Dear colleagues, the bunyaviridae is the largest family of rna viruses, with over 350 isolates worldwide distributed into five genera i. Structural insights into bunyavirus replication and its. Genome termini are generally conserved within but invariably different between bunyavirus genera. Tomato spotted wilt tospovirus genome reassortment and. Bunyaviruses are responsible for a number of febrile diseases in humans and. Mechanistic insight into bunyavirusinduced membrane.
Rodriguez 3, yming bao 4, karla prieto 2, amelia p. Evolutionary persistence of insect bunyavirus infection. Genomic characterization of the genus nairovirus family. Pn sharma department of plant pathology csk hpkv, palampur176062.
As the term implies, large genome dna viruses can also encode many more proteins. It has more than 350 members divided into five genera. All nairovirus nps assume a racketshaped structure with distinct head and stalk domains that are typical for bunyaviruses and unique among. The untranslated regions are represented by a thick black bar. Classification of virus virology online microbiology notes. Genome structure, prevalence, and genetic diversity of niukluk phantom orthophasmavirus. Discovery of novel thrips vector proteins that bind to the. Tomato spotted wilt tospovirus genome reassortment and genome. Pdf bunyaviridae family is the largest and most diverse family of rna viruses.