scholarly journals Genome Organization and Reverse Genetic Analysis of a Type I Feline Coronavirus

2007 ◽  
Vol 82 (4) ◽  
pp. 1851-1859 ◽  
Author(s):  
Gergely Tekes ◽  
Regina Hofmann-Lehmann ◽  
Iris Stallkamp ◽  
Volker Thiel ◽  
Heinz-Jürgen Thiel

ABSTRACT In this study we report the complete sequence and genome organization of the serotype I feline coronavirus (FCoV) strain Black. Furthermore, a reverse genetic system was established for this FCoV strain by cloning a full-length cDNA copy into vaccinia virus. This clone served as basis for the generation of recombinant FCoV (recFCoV) that was shown to bear the same features in vitro as the parental FCoV. Using this system, accessory 3abc genes in the FCoV genome were replaced by green fluorescent protein (recFCoV-GFP) and Renilla luciferase genes (recFCoV-RL). In addition, we showed that feline CD14+ blood monocytes and dendritic cells can be easily detected after infection with recFCoV-GFP. Thus, our established reverse genetic system provides a suitable tool to study the molecular biology of serotype I FCoV.

2021 ◽  
Author(s):  
Melle Holwerda ◽  
Laura Laloli ◽  
Manon Wider ◽  
Lutz Schönecker ◽  
Jens Becker ◽  
...  

AbstractThe ruminant-associated Influenza D virus (IDV) has a broad host tropism and was shown to have zoonotic potential. To identify and characterize molecular viral determinants influencing the host spectrum of IDV, a reverse genetic system is required. For this, we first performed 5′ and 3′ rapid amplification of cDNA ends (RACE) of all seven genomic segments, followed by assessment of the 5′ and 3′ NCR activity prior to constructing the viral genomic segments of a contemporary Swiss bovine IDV isolate (D/CN286) into the bidirectional pHW-2000 vector. The bidirectional plasmids were transfected in HRT-18G cells followed by viral rescue on the same cell type. Analysis of the segment specific 5′ and 3′ non-coding regions (NCR) highlighted that the terminal 3′ end of all segments harbours an Uracil instead of a Cytosine nucleotide, similar to other Influenza viruses. Subsequent analysis on the functionality of the 5′ and 3′ NCR in a minireplicon assay revealed that these sequences were functional and that the variable sequence length of the 5′ and 3′ NCR influences reporter gene expression. Thereafter, we evaluated the replication efficiency of the reverse genetic clone on conventional cell lines of human, swine and bovine origin by use of an in vitro model recapitulating the natural replicate site of IDV in bovine and swine. This revealed that the reverse genetic clone D/CN286 replicates efficiently in all cell culture models. Combined, these results demonstrate the successful establishment of a reverse genetic system from a contemporary bovine IDV isolate that can be used for future identification and characterization of viral determinants influencing the broad host tropism of IDV.


Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 502
Author(s):  
Melle Holwerda ◽  
Laura Laloli ◽  
Manon Wider ◽  
Lutz Schönecker ◽  
Jens Becker ◽  
...  

The ruminant-associated influenza D virus (IDV) has a broad host tropism and was shown to have zoonotic potential. To identify and characterize molecular viral determinants influencing the host spectrum of IDV, a reverse genetic system is required. For this, we first performed 5′ and 3′ rapid amplification of cDNA ends (RACE) of all seven genomic segments, followed by assessment of the 5′ and 3′ NCR activity prior to constructing the viral genomic segments of a contemporary Swiss bovine IDV isolate (D/CN286) into the bidirectional pHW2000 vector. The bidirectional plasmids were transfected in HRT-18G cells followed by viral rescue on the same cell type. Analysis of the segment specific 5′ and 3′ non-coding regions (NCR) highlighted that the terminal 3′ end of all segments harbours an uracil instead of a cytosine nucleotide, similar to other influenza viruses. Subsequent analysis on the functionality of the 5′ and 3′ NCR in a minireplicon assay revealed that these sequences were functional and that the variable sequence length of the 5′ and 3′ NCR influences reporter gene expression. Thereafter, we evaluated the replication efficiency of the reverse genetic clone on conventional cell lines of human, swine and bovine origin, as well as by using an in vitro model recapitulating the natural replication site of IDV in bovine and swine. This revealed that the reverse genetic clone D/CN286 replicates efficiently in all cell culture models. Combined, these results demonstrate the successful establishment of a reverse genetic system from a contemporary bovine IDV isolate that can be used for future identification and characterization of viral determinants influencing the broad host tropism of IDV.


2005 ◽  
Vol 79 (6) ◽  
pp. 3391-3400 ◽  
Author(s):  
Steven M. Sperry ◽  
Lubna Kazi ◽  
Rachel L. Graham ◽  
Ralph S. Baric ◽  
Susan R. Weiss ◽  
...  

ABSTRACT A reverse genetic system was recently established for the coronavirus mouse hepatitis virus strain A59 (MHV-A59), in which cDNA fragments of the RNA genome are assembled in vitro into a full-length genome cDNA, followed by electroporation of in vitro-transcribed genome RNA into cells with recovery of viable virus. The “in vitro-assembled” wild-type MHV-A59 virus (icMHV-A59) demonstrated replication identical to laboratory strains of MHV-A59 in tissue culture; however, icMHV-A59 was avirulent following intracranial inoculation of C57BL/6 mice. Sequencing of the cloned genome cDNA fragments identified two single-nucleotide mutations in cloned genome fragment F, encoding a Tyr6398His substitution in open reading frame (ORF) 1b p59-nsp14 and a Leu94Pro substitution in the ORF 2a 30-kDa protein. The mutations were repaired individually and together in recombinant viruses, all of which demonstrated wild-type replication in tissue culture. Following intracranial inoculation of mice, the viruses encoding Tyr6398His/Leu94Pro substitutions and the Tyr6398His substitution alone demonstrated log10 50% lethal dose (LD50) values too great to be measured. The Leu94Pro mutant virus had reduced but measurable log10 LD50, and the “corrected” Tyr6398/Leu94 virus had a log10 LD50 identical to wild-type MHV-A59. The experiments have defined residues in ORF 1b and ORF 2a that attenuate virus replication and virulence in mice but do not affect in vitro replication. The results suggest that these proteins serve roles in pathogenesis or virus survival in vivo distinct from functions in virus replication. The study also demonstrates the usefulness of the reverse genetic system to confirm the role of residues or proteins in coronavirus replication and pathogenesis.


Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 948
Author(s):  
Sabrina Foscaldi ◽  
María Eugenia Loureiro ◽  
Claudia Sepúlveda ◽  
Carlos Palacios ◽  
María Belén Forlenza ◽  
...  

Mammarenaviruses are enveloped and segmented negative-stranded RNA viruses that comprise several pathogenic members associated with severe human hemorrhagic fevers. Tacaribe virus (TCRV) is the prototype for the New World group of mammarenaviruses and is not only naturally attenuated but also phylogenetically and antigenically related to all South American pathogenic mammarenaviruses, particularly the Junín virus (JUNV), which is the etiological agent of Argentinian hemorrhagic fever (AHF). Moreover, since TCRV protects guinea pigs and non-human primates from lethal challenges with pathogenic strains of JUNV, it has already been considered as a potential live-attenuated virus vaccine candidate against AHF. Here, we report the development of a reverse genetic system that relies on T7 polymerase-driven intracellular expression of the complementary copy (antigenome) of both viral S and L RNA segments. Using this approach, we successfully recovered recombinant TCRV (rTCRV) that displayed growth properties resembling those of authentic TCRV. We also generated a chimeric recombinant TCRV expressing the JUNV glycoproteins, which propagated similarly to wild-type rTCRV. Moreover, a controlled modification within the S RNA 5′ non-coding terminal sequence diminished rTCRV propagation in a cell-type dependent manner, giving rise to new perspectives where the incorporation of additional attenuation markers could contribute to develop safe rTCRV-based vaccines against pathogenic mammarenaviruses.


2019 ◽  
Vol 15 (5) ◽  
pp. 499-505 ◽  
Author(s):  
Duo Zhou ◽  
Meng-Ying Zhu ◽  
Yi-Long Wang ◽  
Xiao-Qiang Hao ◽  
Dong-Ming Zhou ◽  
...  

2007 ◽  
Vol 18 (8) ◽  
pp. 2893-2903 ◽  
Author(s):  
Sarah L. Barker ◽  
Linda Lee ◽  
B. Daniel Pierce ◽  
Lymarie Maldonado-Báez ◽  
David G. Drubin ◽  
...  

The yeast endocytic scaffold Pan1 contains an uncharacterized proline-rich domain (PRD) at its carboxy (C)-terminus. We report that the pan1-20 temperature-sensitive allele has a disrupted PRD due to a frame-shift mutation in the open reading frame of the domain. To reveal redundantly masked functions of the PRD, synthetic genetic array screens with a pan1ΔPRD strain found genetic interactions with alleles of ACT1, LAS17 and a deletion of SLA1. Through a yeast two-hybrid screen, the Src homology 3 domains of the type I myosins, Myo3 and Myo5, were identified as binding partners for the C-terminus of Pan1. In vitro and in vivo assays validated this interaction. The relative timing of recruitment of Pan1-green fluorescent protein (GFP) and Myo3/5-red fluorescent protein (RFP) at nascent endocytic sites was revealed by two-color real-time fluorescence microscopy; the type I myosins join Pan1 at cortical patches at a late stage of internalization, preceding the inward movement of Pan1 and its disassembly. In cells lacking the Pan1 PRD, we observed an increased lifetime of Myo5-GFP at the cortex. Finally, Pan1 PRD enhanced the actin polymerization activity of Myo5–Vrp1 complexes in vitro. We propose that Pan1 and the type I myosins interactions promote an actin activity important at a late stage in endocytic internalization.


Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 576 ◽  
Author(s):  
Tomomi Takano ◽  
Kumi Satoh ◽  
Tomoyoshi Doki ◽  
Taishi Tanabe ◽  
Tsutomu Hohdatsu

Feline infectious peritonitis (FIP) is a viral disease with a high morbidity and mortality by the FIP virus (FIPV, virulent feline coronavirus). Several antiviral drugs for FIP have been identified, but many of these are expensive and not available in veterinary medicine. Hydroxychloroquine (HCQ) is a drug approved by several countries to treat malaria and immune-mediated diseases in humans, and its antiviral effects on other viral infections (e.g., SARS-CoV-2, dengue virus) have been confirmed. We investigated whether HCQ in association with interferon-ω (IFN-ω) is effective for FIPV in vitro. A total of 100 μM of HCQ significantly inhibited the replication of types I and II FIPV. Interestingly, the combination of 100 μM of HCQ and 104 U/mL of recombinant feline IFN-ω (rfIFN-ω, veterinary registered drug) increased its antiviral activity against type I FIPV infection. Our study suggested that HCQ and rfIFN-ω are applicable for treatment of FIP. Further clinical studies are needed to verify the combination of HCQ and rIFN-ω will be effective and safe treatment for cats with FIP.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Dongjie Chen ◽  
Di Wang ◽  
Fang Wei ◽  
Yufang Kong ◽  
Junhua Deng ◽  
...  

Abstract Background Akabane virus (AKAV) is an important insect-borne virus which is widely distributed throughout the world except the Europe and is considered as a great threat to herbivore health. Results An AKAV strain defined as TJ2016 was firstly isolated from the bovine sera in China in 2016. Sequence analysis of the S and M segments suggested that the isolated AKAV strain was closely related to the AKAV strains JaGAr39 and JaLAB39, which belonged to AKAV genogroup II. To further study the pathogenic mechanism of AKAV, the full-length cDNA clone of TJ2016 S, M, and L segment was constructed separately into the TVT7R plasmid at the downsteam of T7 promoter and named as TVT7R-S, TVT7R-M, and TVT7R-L, respectively. The above three plasmids were further transfected into the BSR-T7/5 cells simultaneously with a ratio of 1:1:1 to produce the rescued virus AKAV. Compared with the parental wild type AKAV (wtAKAV), the rescued virus (rAKAV) was proved to be with similar cytopathic effects (CPE), plaque sizes and growth kinetics in BHK-21 cells. Conclusion We successfully isolated a AKAV strain TJ2016 from the sera of cattle and established a reverse genetic platform for AKAV genome manipulation. The established reverse genetic system is also a powerful tool for further research on AKAV pathogenesis and even vaccine studies.


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