Identification of a Trypsin-Like Serine Proteinase Domain Encoded by ORF la of the Coronavirus IBV

Liu, D. X.; Brierley, Ian; Brown, T. D. K.

doi:10.1007/978-1-4615-1899-0_66

Cited by 12 publications

(14 citation statements)

References 17 publications

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“…This may be attributed to the earlier and higher replication of both AIV-H9N2 and classical IBV viruses as indicated by higher viruses shedding titers as early as 2 DPI. These results and previous studies results indicate the possible synergistic mechanism between IBV and AIV-H9N2 possibly by trypsin-like proteases encoded by coronaviruses that enhance the AIV-H9N2 hemagglutinin cleavage (Haghighat-Jahromi et al, 2008;Klenk and Garten, 1994;Liu et al, 1995;Ng and Liu, 2000;Perk et al, 2004).…”

Section: Discussionsupporting

confidence: 80%

Experimental co-infection of infectious bronchitis and low pathogenic avian influenza H9N2 viruses in commercial broiler chickens

Hassan

Ali

Shany

et al. 2017

Research in Veterinary Science

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In this study, commercial broilers were experimentally infected with single (classical IBV, variant IBV or AIV-H9N2) or mixed AIV-H9N2 with classical, variant or vaccine strains of IBV. Birds were monitored for clinical and pathological outcomes and virus shedding for 10days post infection (DPI). Clinical signs were limited to the respiratory tract in all challenged groups and varied from mild to moderate mouth breathing to severe respiratory signs with snorting sound and extended head. Mortalities were only recorded in mixed AIV-H9N2/variant IBV challenge group. AIV-H9N2 challenge caused tracheal petechial hemorrhage that progressed to tracheal congestion and caseation. In mixed AIV-H9N2/IBV vaccine challenge, severe tracheitis with bronchial cast formation was observed. In mixed AIV-H9N2/variant IBV challenge severe congestion of the tracheal mucosa and excessive exudates with a tendency to form tubular casts were observed. Kidney ureate deposition was only observed in variant IBV challenge group. Histopathologically, tracheal congestion, severe degeneration, and deciliation were noticed in all groups of mixed infection. Interestingly, hemorrhage and atrophy were observed in thymus gland of birds challenged with single AIV-H9N2 or mixed AIV-H9N2/IBV. There was no difference in the tracheal shedding level of variant IBV between single and mixed infected groups while classical IBV shedding increased in mixed infection group. Interestingly, the AIV-H9N2 showed constantly high shedding titers till 7DPI with variant or vaccine IBV co-infection. In conclusion, co-infection of IBV and AIV-H9N2 induced severe clinical outcome and high mortality. Also, IBV co-infection increased the shedding of AIV-H9N2 in experimentally infected birds.

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Section: Discussionsupporting

confidence: 80%

Experimental co-infection of infectious bronchitis and low pathogenic avian influenza H9N2 viruses in commercial broiler chickens

Hassan

Ali

Shany

et al. 2017

Research in Veterinary Science

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“…IBLV coinfection may have provided the enzymes and enhanced H9N2 pathogenicity in this experiment. It has been reported that a trypsin-like serine protease domain is encoded by coronavirus IBV [20,24]. The presence of similar enzymes in the field situation could possibly increase the pathogenicity of H9N2 AIV.…”

Section: Discussionmentioning

confidence: 99%

“…Antibiotics and antifungal materials were used as described above. The eggs were incubated in a stationary incubator at 37°C and 55% relative humidity for 48 h. The allantoic fluids were harvested at 0, 16,18,20,22,24,26,28,30,44,46 and 48 h post-inoculation in each group. Serial twofold dilutions of the allantoic fluid (50 ll) in PBS (pH 7.2) were mixed with 50 ll of a 1% washed chicken red blood cell suspension, then HA titers were read 30 min later at room temperature [7].…”

Section: Ha Activity Of Avian Influenza Virus In Embryonated Chicken mentioning

confidence: 99%

Coinfection of avian influenza virus (H9N2 subtype) with infectious bronchitis live vaccine

et al. 2008

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Avian influenza virus of H9N2 subtype is pathotyped as a non-highly pathogenic virus. However, frequent incidences of avian influenza of high mortality that are caused by H9N2 viruses have been observed in broiler chicken farms in Iran and some other Asian countries. Coinfections or environmental factors may be involved in such cases. Infectious microorganisms have been implicating in taking part in the cases of coinfection. We studied the effect of experimental coinfection of H9N2 avian influenza virus with infectious bronchitis live vaccine, which is used extensively in chicken farms in Iran. Clinical signs, gross lesions, viral shedding and mortality rate of the experimentally infected birds were examined. Coinfection of infectious bronchitis live vaccine and H9N2 avian influenza virus led to an extension of the shedding period of H9N2 virus, increasing the severity of clinical signs and mortality rates, causing macroscopic lesions in the embryos.

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“…Until now, SARS-CoV PL2 pro was the only structurally characterized representative of the coronaviral PL pro enzymes (58). Gammacoronaviruses encode an active PL2 pro (44) but also carry an inactive remnant of PL1 pro (71). Moreover, their replicase lacks an nsp1 moiety, and therefore, PL2 pro cleaves only the nsp2Խnsp3 and nsp3Խnsp4 sites.…”

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confidence: 99%

Papain-Like Protease 1 from Transmissible Gastroenteritis Virus: Crystal Structure and Enzymatic Activity toward Viral and Cellular Substrates

Wojdyla

Manolaridis

Kasteren

et al. 2010

J Virol

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Coronaviruses encode two classes of cysteine proteases, which have narrow substrate specificities and either a chymotrypsin-or papain-like fold. These enzymes mediate the processing of the two precursor polyproteins of the viral replicase and are also thought to modulate host cell functions to facilitate infection. The papain-like protease 1 (PL1 pro ) domain is present in nonstructural protein 3 (nsp3) of alphacoronaviruses and subgroup 2a betacoronaviruses. It participates in the proteolytic processing of the N-terminal region of the replicase polyproteins in a manner that varies among different coronaviruses and remains poorly understood. Here we report the first structural and biochemical characterization of a purified coronavirus PL1 pro domain, that of transmissible gastroenteritis virus (TGEV). Its tertiary structure is compared with that of severe acute respiratory syndrome (SARS) coronavirus PL2 pro , a downstream paralog that is conserved in the nsp3's of all coronaviruses. We identify both conserved and unique structural features likely controlling the interaction of PL1 pro with cofactors and substrates, including the tentative mapping of substrate pocket residues. The purified recombinant TGEV PL1 pro was shown to cleave a peptide mimicking the cognate nsp2Խnsp3 cleavage site. Like its PL2 pro paralogs from several coronaviruses, TGEV PL1 pro was also found to have deubiquitinating activity in an in vitro cleavage assay, implicating it in counteracting ubiquitin-regulated host cell pathways, likely including innate immune responses. In combination with the prior characterization of PL2 pro from other alphacoronaviruses, e.g., human coronaviruses 229E and NL63, our results unequivocally establish that these viruses employ two PL pro s with overlapping specificities toward both viral and cellular substrates.Coronaviruses (CoVs) are enveloped, positive-stranded RNA viruses with a large genome of 26 to 31 kb. They belong to the order Nidovirales and include important pathogens of humans and other animals (22, 66). The coronavirus nonstructural proteins (nsp's) are encoded within the first two open reading frames (ORFs) (ORF1a and ORF1b), which comprise approximately the 5Ј-proximal two-thirds of the viral genome. These two ORFs are translated into two large polyproteins, pp1a and pp1ab, with the expression of the latter involving a ribosomal frameshift mechanism (8). The autoproteolytic processing of pp1a and pp1ab gives rise to a total of 15 or 16 mature nsp's. These proteins assemble into the viral replicase/ transcriptase complex (RTC), which is associated with an intricate network of modified endoplasmic reticulum (ER) membranes and supports the synthesis of genomic RNA (replication) and subgenomic mRNAs (transcription) (36,55,61,62).The recently established Coronavirinae subfamily of the family Coronaviridae is subdivided into the genera Alphacoronavirus, Betacoronavirus, and Gammacoronavirus, which include phylogenetically compact genogroups (25, 38) whose numbers are growing rapidly (45, 67). The...

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Identification of a Trypsin-Like Serine Proteinase Domain Encoded by ORF la of the Coronavirus IBV

Cited by 12 publications

References 17 publications

Experimental co-infection of infectious bronchitis and low pathogenic avian influenza H9N2 viruses in commercial broiler chickens

Experimental co-infection of infectious bronchitis and low pathogenic avian influenza H9N2 viruses in commercial broiler chickens

Coinfection of avian influenza virus (H9N2 subtype) with infectious bronchitis live vaccine

Papain-Like Protease 1 from Transmissible Gastroenteritis Virus: Crystal Structure and Enzymatic Activity toward Viral and Cellular Substrates

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