Sequence and transcriptional analysis of terminal regions of the fowl adenovirus type 8 genome.

Cao, Jingxin; Krell, Peter J.; Nagy, Éva

doi:10.1099/0022-1317-79-10-2507

Cited by 27 publications

(27 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These cysteines are positioned at Ϫ4, ϩ6, ϩ10, and ϩ 21 relative to the vLIP serine nucleophile position (Fig. 2a) and are absolutely conserved among vLIP homologues in the MD-like genus as well as in the avian adenoviruses (20,23,37,59,80). Cysteine residues are not found so close to the nucleophile position in any characterized cellular lipase.…”

Section: Discussionmentioning

confidence: 99%

“…The ORF in question, originally designated LORF2, was hence termed "viral lipase," or vLIP (49). The vLIP reading frame is conserved among all three members of the Marek's disease-like virus genus (3,41,46,49,78), and homologues are also found in certain avian adenoviruses (20,23,37,59,80). The complete vLIP ORF is 756 amino acids in length, and significant homology to pancreatic lipases is found in a stretch of approximately 141 amino acids that span positions 229 to 369.…”

mentioning

confidence: 99%

See 1 more Smart Citation

vLIP, a Viral Lipase Homologue, Is a Virulence Factor of Marek's Disease Virus

Kamil

Tischer

Trapp

et al. 2005

J Virol

View full text Add to dashboard Cite

The genome of Marek's disease virus (MDV) has been predicted to encode a secreted glycoprotein, vLIP, which bears significant homology to the ␣/␤ hydrolase fold of pancreatic lipases. Here it is demonstrated that MDV vLIP mRNA is produced via splicing and that vLIP is a late gene, due to its sensitivity to inhibition of DNA replication. While vLIP was found to conserve several residues essential to hydrolase activity, an unfavorable asparagine substitution is present at the lipase catalytic triad acid position. Consistent with structural predictions, purified recombinant vLIP did not show detectable activity on traditional phospholipid or triacylglyceride substrates. Two different vLIP mutant viruses, one bearing a 173-amino-acid deletion in the lipase homologous domain, the other having an alanine point mutant at the serine nucleophile position, caused a significantly lower incidence of Marek's disease in chickens and resulted in enhanced survival relative to two independently produced vLIP revertants or parental virus. These data provide the first evidence that vLIP enhances the replication and pathogenic potential of MDV. Furthermore, while vLIP may not serve as a traditional lipase enzyme, the data indicate that the serine nucleophile position is nonetheless essential in vivo for the viral functions of vLIP. Therefore, it is suggested that this particular example of lipase homology may represent the repurposing of an ␣/␤ hydrolase fold toward a nonenzymatic role, possibly in lipid bonding.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

vLIP, a Viral Lipase Homologue, Is a Virulence Factor of Marek's Disease Virus

Kamil

Tischer

Trapp

et al. 2005

J Virol

View full text Add to dashboard Cite

show abstract

“…Human adenoviruses (type 2 and 5) have been for some time developed as gene delivery vectors for vaccination or gene therapy (2,9,17,24,35,36) and more recently, adenoviruses from various species (bovine, ovine, porcine, canine, and avian) have been studied for similar applications (11,16,23,25,28,29,30,32). Among avian adenoviruses, which include at least 10 serotypes (3,4,8,12,27,32), chicken embryo lethal orphan (CELO), which represents serotype 1, is the best characterized (6,7,19,20,22,23,26). The CELO virus genome is 43,804 bp long and has been completely sequenced (7), and its transcriptional organization has been established (26).…”

mentioning

confidence: 99%

Construction of Avian Adenovirus CELO Recombinants in Cosmids

François¹,

Eterradossi

Delmas

et al. 2001

J Virol

View full text Add to dashboard Cite

The avian adenovirus CELO is a promising vector for gene transfer applications. In order to study this potentiality, we developed an improved method for construction of adenovirus vectors in cosmids that was used to engineer the CELO genome. For all the recombinant viruses constructed by this method, the ability to produce infectious particles and the stability of the genome were evaluated in a chicken hepatocarcinoma cell line (LMH cell line). Our aim was to develop a replication-competent vector for vaccination of chickens, so we first generated knockout point mutations into 16 of the 22 unassigned CELO open reading frames (ORFs) to determine if they were essential for virus replication. As the 16 independent mutant viruses replicated in our cellular system, we constructed CELO genomes with various deletions in the regions of these nonessential ORFs. An expression cassette coding for the enhanced green fluorescent protein (eGFP) was inserted in place of these deletions to easily follow expression of the transgene and propagation of the vector in cell monolayers. Height-distinct GFP-expressing CELO vectors were produced that were all replication competent in our system. We then retained the vector backbone with the largest deletion (i.e., 3.6 kb) for the construction of vectors carrying cDNA encoding infectious bursal disease virus proteins. These CELO vectors could be useful for vaccination in the chicken species.Members of the family Adenoviridae are nonenveloped viruses with double-stranded linear DNA genomes that are 25 to 45 kb in length (13). Human adenoviruses (type 2 and 5) have been for some time developed as gene delivery vectors for vaccination or gene therapy (2,9,17,24,35,36) and more recently, adenoviruses from various species (bovine, ovine, porcine, canine, and avian) have been studied for similar applications (11,16,23,25,28,29,30,32). Among avian adenoviruses, which include at least 10 serotypes (3,4,8,12,27,32), chicken embryo lethal orphan (CELO), which represents serotype 1, is the best characterized (6,7,19,20,22,23,26). The CELO virus genome is 43,804 bp long and has been completely sequenced (7), and its transcriptional organization has been established (26). The central region of the viral genome is strongly homologous with other adenoviruses: the lower strand encodes replication functions (DNA polymerase, DNA-binding protein, pTP), and the upper strand, which is transcribed under the control of a single major late promoter, encodes capsid structural proteins. On either side of this central part there are two regions encoding at least 22 unassigned open reading frames (ORFs) that have no sequence homology with the E1, E3, and E4 regions of mammalian adenoviruses (mastadenoviruses). Only 2 of these 22 genes have been studied: ORF8 encodes GAM-1 protein, which was identified as a functional homolog to human adenovirus E1B 19K protein (6), and ORF22 encodes a protein that interacts with the retinoblastoma protein, which is similar to human adenovirus E1A protein, and cooperates with GAM-1 ...

show abstract

“…AC_000013). In those annotations, ORFs 14 and 24 appear to be 59 and 27 aa longer at their N termini, respectively, due to theoretical predictions of a common 59 exon at nt 16276-16281 and additional DNA sequences upstream of the initiation codons, as demonstrated by Cao et al (1998) and Ojkic et al (2002) (171 and 105 bp for ORFs 14 and 24, respectively). As these exons were absent from our ORF14, 15 and 24 expression plasmids, the possibility that ORFs 14 and 24 were non-functional due to truncations at the N terminus should be considered.…”

Section: Discussionmentioning

confidence: 99%

A region at the left end of the fowl adenovirus 9 genome that is non-essential in vitro has consequences in vivo

Corredor

Nagy

2009

Journal of General Virology

View full text Add to dashboard Cite

The regions at the left and right ends of fowl adenovirus (FAdV) genomes are not wellcharacterized in comparison to those of human adenoviruses. Using a series of deletion mutants, we analysed a 2.4 kb region near the left end of the FAdV-9 genome (nt 400-2782) that contains packaging-signal motifs VI and VII and open reading frames (ORFs) 0, 1, 1A, 1B, 1C and 2. Viable viruses with specific deletions in this region had wild-type characteristics in vitro, as measured by cytopathic effect, plaque morphology, virus titres and growth kinetics. However, one mutant (FAdV-9D4), which lacked these ORFs and retained the packaging motifs, did not replicate at wild-type levels in vivo, as judged in infected eggs by virus titres in allantoic fluid and in infected chickens by antibody responses, virus titres in faeces and virus genome copy numbers in tissues. These findings indicate that some of the ORFs in this region, although dispensable in vitro, are important for in vivo replication of FAdV-9. INTRODUCTIONFowl adenoviruses (FAdVs) have a worldwide distribution, and some are important poultry pathogens that cause inclusion body hepatitis and hydropericardium syndrome in chickens (Adair & Fitzgerald, 2008). FAdV serotypes are grouped into five species (Fowl adenovirus A-E), all belonging to the genus Aviadenovirus, family Adenoviridae (Benkő et al., 2005). Complete nucleotide sequences are available for the genomes of FAdV-1 (CELO virus) and FAdV-9 (strain A-2A) (Chiocca et al., 1996;Ojkic & Nagy, 2000), and partial nucleotide sequences are also available for the left and right ends of the genomes of FAdV-2, -4, -8 and -10 (strain C-2B) (Corredor et al., 2006(Corredor et al., , 2008. None of the early genes at the left and right ends of the FAdV genomes are homologues of the E1, E3 and E4 genes of mastadenoviruses, which infect mammals Chiocca et al., 1996). In this study, the importance of ORFs at the left end of the FAdV-9 genome in virus replication in vitro and in vivo was investigated by analysing deletions, as a first step towards elucidating the roles of the early genes in this region. RESULTS Generation of deletionsThe ORF arrangement within the left-end genomic region of FAdV-9 and the features of all deletions are depicted in Fig. 1(a, b), respectively. Nine deletions were generated in the region within nt 250-4200 of the FAdV-9 genome as shown: FAdV-9D1 (D1194-2342), FAdV-9D2 (D854-2782), FAdV-9D3 (D854-2817), FAdV-9D4 (D491-2782), FAdV-9D5 (D491-2980), FAdV-9D6 (D491-4200), FAdV-9D7 (D400-2782), FAdV-9D8 (D330-2782) and FAdV-9D9 (D250-2782). Viable viruses were recovered following transfection of CH-SAH (chicken hepatoma) cells without complementation with only the FAdV-9D1, -9D2, -9D4 and -9D7 genomes at 5-7 days post-transfection (p.t.). The first viable deletion mutant, FAdV-9D1, was generated by Supplementary methods and a supplementary figure and table are available with the online version of this paper.

show abstract

Sequence and transcriptional analysis of terminal regions of the fowl adenovirus type 8 genome.

Cited by 27 publications

References 40 publications

vLIP, a Viral Lipase Homologue, Is a Virulence Factor of Marek's Disease Virus

vLIP, a Viral Lipase Homologue, Is a Virulence Factor of Marek's Disease Virus

Construction of Avian Adenovirus CELO Recombinants in Cosmids

A region at the left end of the fowl adenovirus 9 genome that is non-essential in vitro has consequences in vivo

Contact Info

Product

Resources

About