scholarly journals Exceptionally diverse morphotypes and genomes of crenarchaeal hyperthermophilic viruses

2004 ◽  
Vol 32 (2) ◽  
pp. 204-208 ◽  
Author(s):  
D. Prangishvili ◽  
R.A. Garrett
Keyword(s):  
Aquatic Ecosystems ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Open Reading Frames ◽  
Dna Viruses ◽  
Double Stranded Dna ◽  
Sequence Patterns ◽  
Hydrothermal Environments ◽  
Homologous Orfs ◽  
Reading Frames

The remarkable diversity of the morphologies of viruses found in terrestrial hydrothermal environments with temperatures >80°C is unprecedented for aquatic ecosystems. The best-studied viruses from these habitats have been assigned to novel viral families: Fuselloviridae, Lipothrixviridae and Rudiviridae. They all have double-stranded DNA genomes and infect hyperthermophilic crenarchaea of the orders Sulfolobales and Thermoproteales. Representatives of the different viral families share a few homologous ORFs (open reading frames). However, about 90% of all ORFs in the seven sequenced genomes show no significant matches to sequences in public databases. This suggests that these hyperthermophilic viruses have exceptional biochemical solutions for biological functions. Specific features of genome organization, as well as strategies for DNA replication, suggest that phylogenetic relationships exist between crenarchaeal rudiviruses and the large eukaryal DNA viruses: poxviruses, the African swine fever virus and Chlorella viruses. Sequence patterns at the ends of the linear genome of the lipothrixvirus AFV1 are reminiscent of the telomeric ends of linear eukaryal chromosomes and suggest that a primitive telomeric mechanism operates in this virus.

scholarly journals Pacmanvirus, a New Giant Icosahedral Virus at the Crossroads between Asfarviridae and Faustoviruses

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Julien Andreani ◽  
Jacques Yaacoub Bou Khalil ◽  
Madhumati Sevvana ◽  
Samia Benamar ◽  
Fabrizio Di Pinto ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
Acanthamoeba Castellanii ◽  
Genomic Analysis ◽  
African Swine Fever ◽  
Fever Virus ◽  
Dna Virus ◽  
Dna Viruses ◽  
Content Type ◽  
Double Stranded Dna ◽  
Protein Locus

ABSTRACT African swine fever virus, a double-stranded DNA virus that infects pigs, is the only known member of the Asfarviridae family. Nevertheless, during our isolation and sequencing of the complete genome of faustovirus, followed by the description of kaumoebavirus, carried out over the past 2 years, we observed the emergence of previously unknown related viruses within this group of viruses. Here we describe the isolation of pacmanvirus, a fourth member in this group, which is capable of infecting Acanthamoeba castellanii. Pacmanvirus A23 has a linear compact genome of 395,405 bp, with a 33.62% G+C content. The pacmanvirus genome harbors 465 genes, with a high coding density. An analysis of reciprocal best hits shows that 31 genes are conserved between African swine fever virus, pacmanvirus, faustovirus, and kaumoebavirus. Moreover, the major capsid protein locus of pacmanvirus appears to be different from those of kaumoebavirus and faustovirus. Overall, comparative and genomic analyses reveal the emergence of a new group or cluster of viruses encompassing African swine fever virus, faustovirus, pacmanvirus, and kaumoebavirus. IMPORTANCE Pacmanvirus is a newly discovered icosahedral double-stranded DNA virus that was isolated from an environmental sample by amoeba coculture. We describe herein its structure and replicative cycle, along with genomic analysis and genomic comparisons with previously known viruses. This virus represents the third virus, after faustovirus and kaumoebavirus, that is most closely related to classical representatives of the Asfarviridae family. These results highlight the emergence of previously unknown double-stranded DNA viruses which delineate and extend the diversity of a group around the asfarvirus members.

scholarly journals Inhibition of a Large Double-Stranded DNA Virus by MxA Protein

2008 ◽  
Vol 83 (5) ◽  
pp. 2310-2320 ◽  
Author(s):  
Christopher L. Netherton ◽  
Jennifer Simpson ◽  
Otto Haller ◽  
Thomas E. Wileman ◽  
Haru-Hisa Takamatsu ◽  
...  
Keyword(s):  
Rna Viruses ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Vero Cells ◽  
Dna Virus ◽  
Dna Viruses ◽  
Double Stranded Dna ◽  
Late Protein ◽  
B Virus ◽  
Negative Sense

ABSTRACT Increasing evidence points to the importance of the interferon (IFN) response in determining the host range and virulence of African swine fever virus (ASFV). Infection with attenuated strains of ASFV leads to the upregulation of genes controlled by IFN pathways, including myxovirus resistance (Mx) genes that are potent effectors of the antiviral state. Mx gene products are known to inhibit the replication of many negative-sense single-stranded RNA viruses, as well as double-stranded RNA viruses, positive-sense single-stranded RNA viruses, and the reverse-transcribing DNA virus hepatitis B virus. Here, we provide data that extend the known range of viruses inhibited by Mx to include the large double-stranded DNA viruses. Stably transfected Vero cells expressing human MxA protein did not support ASFV plaque formation, and virus replication in these cells was reduced 100-fold compared with that in control cells. In contrast, ASFV replication in cells expressing MxB protein or a mutant MxA protein was similar to that in control Vero cells. There was a drastic reduction in ASFV late protein synthesis in MxA-expressing cells, correlating with the results of previous work on the effect of IFN on viral replication. Strikingly, the inhibition of ASFV replication was linked to the recruitment of MxA protein to perinuclear viral assembly sites, where the protein surrounded the virus factories. Interactions between ASFV and MxA were similar to those seen between MxA and different RNA viruses, suggesting a common inhibitory mechanism.

scholarly journals Autophagy impairment by African swine fever virus

2021 ◽  
Vol 102 (8) ◽  
Author(s):  
Gareth L. Shimmon ◽  
Joshua Y. K. Hui ◽  
Thomas E. Wileman ◽  
Christopher L. Netherton
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Open Reading Frames ◽  
Innate And Adaptive Immunity ◽  
Double Stranded Dna ◽  
Functional Step ◽  
Complex Protein ◽  
Autophagy Pathway ◽  
Domestic Swine

African swine fever is a devastating disease of domestic swine and wild boar caused by a large double-stranded DNA virus that encodes for more than 150 open reading frames. There is no licensed vaccine for the disease and the most promising current candidates are modified live viruses that have been attenuated by deletion of virulence factors. Like many viruses African swine fever virus significantly alters the host cell machinery to benefit its replication and viral genes that modify host pathways represent promising targets for development of gene deleted vaccines. Autophagy is an important cellular pathway that is involved in cellular homeostasis, innate and adaptive immunity and therefore is manipulated by a number of different viruses. Autophagy is regulated by a complex protein cascade and here we show that African swine fever virus can block formation of autophagosomes, a critical functional step of the autophagy pathway through at least two different mechanisms. Interestingly this does not require the A179L gene that has been shown to interact with Beclin-1, an important autophagy regulator.

scholarly journals The main DNA viruses significantly affecting pig livestock

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Carlos Díaz ◽  
Vladimír Celer ◽  
Ivo Frébort
Keyword(s):  
Immune System ◽  
Pseudorabies Virus ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Host Immune System ◽  
Dna Virus ◽  
Dna Viruses ◽  
Double Stranded Dna ◽  
Porcine Circoviruses

AbstractSwine DNA viruses have developed unique mechanisms for evasion of the host immune system, infection and DNA replication, and finally, construction and release of new viral particles. This article reviews four classes of DNA viruses affecting swine: porcine circoviruses, African swine fever virus, porcine parvoviruses, and pseudorabies virus. Porcine circoviruses belonging to the Circoviridae family are small single-stranded DNA viruses causing different diseases in swine including poly-weaning multisystemic wasting syndrome, porcine dermatitis and nephropathy syndrome, and porcine respiratory disease complex. African swine fever virus, the only member of the Asfivirus genus in the Asfarviridae family, is a large double-stranded DNA virus and for its propensity to cause high mortality, it is currently considered the most dangerous virus in the pig industry. Porcine parvoviruses are small single-stranded DNA viruses belonging to the Parvoviridae family that cause reproductive failure in pregnant gilts. Pseudorabies virus, or suid herpesvirus 1, is a large double-stranded DNA virus belonging to the Herpesviridae family and Alphaherpesvirinae subfamily. Recent findings including general as well as genetic classification, virus structure, clinical syndromes and the host immune system responses and vaccine protection are described for all four swine DNA virus classes.

scholarly journals The Mimivirus L375 Nudix enzyme hydrolyzes the 5’ mRNA cap

2021 ◽  
Author(s):  
Grace Kago ◽  
Susan Parrish
Keyword(s):  
African Swine Fever Virus ◽  
Sequence Similarity ◽  
African Swine Fever ◽  
Host Protein ◽  
Mrna Turnover ◽  
Dna Viruses ◽  
Mrna Decapping ◽  
Double Stranded Dna ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Host Protein Synthesis

AbstractThe giant Mimivirus is a member of the nucleocytoplasmic large DNA viruses (NCLDV), a group of diverse viruses that contain double-stranded DNA (dsDNA) genomes that replicate primarily in eukaryotic hosts. Two members of the NCLDV, Vaccinia Virus (VACV) and African Swine Fever Virus (ASFV), both synthesize Nudix enzymes that have been shown to decap mRNA, a process thought to accelerate viral and host mRNA turnover and promote the shutoff of host protein synthesis. Mimivirus encodes two Nudix enzymes in its genome, denoted as L375 and L534. Importantly, L375 exhibits sequence similarity to ASFV-DP and eukaryotic Dcp2, two Nudix enzymes shown to possess mRNA decapping activity. In this work, we demonstrate that recombinant Mimivirus L375 cleaves the 5’ m7GpppN mRNA cap, releasing m7GDP as a product. L375 did not significantly cleave mRNAs containing an unmethylated 5’GpppN cap, indicating that this enzyme specifically hydrolyzes methylated-capped transcripts. A point mutation in the L375 Nudix motif completely eliminated cap hydrolysis, showing that decapping activity is dependent on this motif. Addition of methylated cap derivatives or uncapped RNA inhibited L375 decapping activity, suggesting that L375 recognizes its substrate through interaction with both the mRNA cap and RNA body.

scholarly journals The Mimivirus L375 Nudix enzyme hydrolyzes the 5’ mRNA cap

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0245820
Author(s):  
Grace Kago ◽  
Susan Parrish
Keyword(s):  
African Swine Fever Virus ◽  
Sequence Similarity ◽  
African Swine Fever ◽  
Host Protein ◽  
Mrna Turnover ◽  
Dna Viruses ◽  
Mrna Decapping ◽  
Double Stranded Dna ◽  
Nucleocytoplasmic Large Dna Viruses ◽  
Host Protein Synthesis

The giant Mimivirus is a member of the nucleocytoplasmic large DNA viruses (NCLDV), a group of diverse viruses that contain double-stranded DNA (dsDNA) genomes that replicate primarily in eukaryotic hosts. Two members of the NCLDV, Vaccinia Virus (VACV) and African Swine Fever Virus (ASFV), both synthesize Nudix enzymes that have been shown to decap mRNA, a process thought to accelerate viral and host mRNA turnover and promote the shutoff of host protein synthesis. Mimivirus encodes two Nudix enzymes in its genome, denoted as L375 and L534. Importantly, L375 exhibits sequence similarity to ASFV-DP and eukaryotic Dcp2, two Nudix enzymes shown to possess mRNA decapping activity. In this work, we demonstrate that recombinant Mimivirus L375 cleaves the 5’ m7GpppN mRNA cap, releasing m7GDP as a product. L375 did not significantly cleave mRNAs containing an unmethylated 5’GpppN cap, indicating that this enzyme specifically hydrolyzes methylated-capped transcripts. A point mutation in the L375 Nudix motif completely eliminated cap hydrolysis, showing that decapping activity is dependent on this motif. Addition of uncapped RNA significantly reduced L375 decapping activity, suggesting that L375 may recognize its substrate through interaction with the RNA body.

scholarly journals Roles of African swine fever virus structural proteins in viral infection

2017 ◽  
Vol 61 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Ning Jia ◽  
Yunwen Ou ◽  
Zygmunt Pejsak ◽  
Yongguang Zhang ◽  
Jie Zhang
Keyword(s):  
Viral Infection ◽  
African Swine Fever Virus ◽  
Control Strategies ◽  
African Swine Fever ◽  
Fever Virus ◽  
Open Reading Frames ◽  
Structural Proteins ◽  
Domestic Pigs ◽  
Virus Particles ◽  
Double Stranded Dna

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.

scholarly journals Human Papillomavirus Type 18 E1 Protein Is Translated from Polycistronic mRNA by a Discontinuous Scanning Mechanism

1999 ◽  
Vol 73 (4) ◽  
pp. 3062-3070 ◽  
Author(s):  
Maido Remm ◽  
Anu Remm ◽  
Mart Ustav
Keyword(s):  
Human Papillomavirus ◽  
Open Reading Frames ◽  
Viral Mrna ◽  
Dna Viruses ◽  
Polycistronic Mrna ◽  
E1 Protein ◽  
Double Stranded Dna ◽  
Infected Cells ◽  
Scanning Mechanism ◽  
Reading Frames

ABSTRACT Papillomaviruses are small double-stranded DNA viruses that replicate episomally in the nuclei of infected cells. The full-length E1 protein of papillomaviruses is required for the replication of viral DNA. The viral mRNA from which the human papillomavirus type 18 E1 protein is expressed is not known. We demonstrate that in eukaryotic cells, the E1 protein is expressed from polycistronic mRNA containing E6, E7, and E1 open reading frames (ORFs). The translation of adjacent E7 and E1 ORFs is not associated; it is performed by separate populations of ribosomes. The translation of the downstream E1 gene is preceded by ribosome scanning. Scanning happens at least at the 5′ end of the polycistronic mRNA and also approximately 100 bp in front of the E1 gene. Long areas in middle of the mRNA are bypassed by ribosomes, possibly by ribosomal “shunting.” Inactivation of short minicistrons in the upstream area of the E1 gene did not change the expression level of the E1 gene.

scholarly journals Bacteriophages LIMElight and LIMEzero of Pantoea agglomerans, Belonging to the “phiKMV-Like Viruses”

2011 ◽  
Vol 77 (10) ◽  
pp. 3443-3450 ◽  
Author(s):  
Evelien M. Adriaenssens ◽  
Pieter-Jan Ceyssens ◽  
Vincent Dunon ◽  
Hans-Wolfgang Ackermann ◽  
Johan Van Vaerenbergh ◽  
...  
Keyword(s):  
Soil Samples ◽  
Pantoea Agglomerans ◽  
Open Reading Frames ◽  
Human Pathogen ◽  
Content Type ◽  
Host Diversity ◽  
Double Stranded Dna ◽  
Opportunistic Human Pathogen ◽  
Reading Frames

ABSTRACTPantoea agglomeransis a common soil bacterium used in the biocontrol of fungi and bacteria but is also an opportunistic human pathogen. It has been described extensively in this context, but knowledge of bacteriophages infecting this species is limited. Bacteriophages LIMEzero and LIMElight ofP. agglomeransare lytic phages, isolated from soil samples, belonging to thePodoviridaeand are the firstPantoeaphages of this family to be described. The double-stranded DNA (dsDNA) genomes (43,032 bp and 44,546 bp, respectively) encode 57 and 55 open reading frames (ORFs). Based on the presence of an RNA polymerase in their genomes and their overall genome architecture, these phages should be classified in the subfamily of theAutographivirinae, within the genus of the “phiKMV-like viruses.” Phylogenetic analysis of all the sequenced members of theAutographivirinaesupports the classification of phages LIMElight and LIMEzero as members of the “phiKMV-like viruses” and corroborates the subdivision into the different genera. These data expand the knowledge ofPantoeaphages and illustrate the wide host diversity of phages within the “phiKMV-like viruses.”

scholarly journals Characterization of Two Virulent Phages of Lactobacillus plantarum

2012 ◽  
Vol 78 (24) ◽  
pp. 8719-8734 ◽  
Author(s):  
Mariángeles Briggiler Marcó ◽  
Josiane E. Garneau ◽  
Denise Tremblay ◽  
Andrea Quiberoni ◽  
Sylvain Moineau
Keyword(s):  
Lactobacillus Plantarum ◽  
Corn Silage ◽  
Open Reading Frames ◽  
High Identity ◽  
Content Type ◽  
Defense Systems ◽  
Double Stranded Dna ◽  
Type Phage ◽  
Reading Frames

ABSTRACTWe characterized twoLactobacillus plantarumvirulent siphophages, ATCC 8014-B1 (B1) and ATCC 8014-B2 (B2), previously isolated from corn silage and anaerobic sewage sludge, respectively. Phage B2 infected two of the eightL. plantarumstrains tested, while phage B1 infected three. Phage adsorption was highly variable depending on the strain used. Phage defense systems were found in at least twoL. plantarumstrains, LMG9211 and WCSF1. The linear double-stranded DNA genome of thepac-type phage B1 had 38,002 bp, a G+C content of 47.6%, and 60 open reading frames (ORFs). Surprisingly, the phage B1 genome has 97% identity with that ofPediococcus damnosusphage clP1 and 77% identity with that ofL. plantarumphage JL-1; these phages were isolated from sewage and cucumber fermentation, respectively. The double-stranded DNA (dsDNA) genome of thecos-type phage B2 had 80,618 bp, a G+C content of 36.9%, and 127 ORFs with similarities to those ofBacillusandLactobacillusstrains as well as phages. Some phage B2 genes were similar to ORFs fromL. plantarumphage LP65 of theMyoviridaefamily. Additionally, 6 tRNAs were found in the phage B2 genome. Protein analysis revealed 13 (phage B1) and 9 (phage B2) structural proteins. To our knowledge, this is the first report describing such high identity between phage genomes infecting different genera of lactic acid bacteria.

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