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A Genomic Approach to Unravel Host-Pathogen Interaction in Chelonians: The Example of Testudinid Herpesvirus 3.

Origgi FC, Tecilla M, Pilo P, Aloisio F, Otten P, Aguilar-Bultet L, Sattler U, Roccabianca P, Romero CH, Bloom DC, Jacobson ER - PLoS ONE (2015)

Bottom Line: Consistently, the phylogenetic analysis positions TeHV3 among the Alphaherpesvirinae, closely associated with Chelonid herpesvirus 5, a Scutavirus.To exemplify the potential benefits of the novel genomic information provided by this first whole genome analysis, we selected the glycoprotein B (gB) gene, for detailed comparison among different TeHV3 isolates.Viral isolation, TeHV identification, phylogenetic analysis and pathological characterization of the associated lesions, were performed.

View Article: PubMed Central - PubMed

Affiliation: Centre for Fish and Wildlife Health (FIWI), Vetsuisse Faculty, University of Bern, Bern, Switzerland.

ABSTRACT
We report the first de novo sequence assembly and analysis of the genome of Testudinid herpesvirus 3 (TeHV3), one of the most pathogenic chelonian herpesviruses. The genome of TeHV3 is at least 150,080 nucleotides long, is arranged in a type D configuration and comprises at least 102 open reading frames extensively co-linear with those of Human herpesvirus 1. Consistently, the phylogenetic analysis positions TeHV3 among the Alphaherpesvirinae, closely associated with Chelonid herpesvirus 5, a Scutavirus. To date, there has been limited genetic characterization of TeHVs and a resolution beyond the genotype was not feasible because of the lack of informative DNA sequences. To exemplify the potential benefits of the novel genomic information provided by this first whole genome analysis, we selected the glycoprotein B (gB) gene, for detailed comparison among different TeHV3 isolates. The rationale for selecting gB is that it encodes for a well-conserved protein among herpesviruses but is coupled with a relevant antigenicity and is consequently prone to accumulate single nucleotide polymorphisms. These features were considered critical for an ideal phylogenetic marker to investigate the potential existence of distinct TeHV3 genogroups and their associated pathology. Fifteen captive tortoises presumptively diagnosed to be infected with TeHVs or carrying compatible lesions on the basis of either the presence of intranuclear inclusions (presumptively infected) and/or diphtheronecrotic stomatitis-glossitis or pneumonia (compatible lesions) were selected for the study. Viral isolation, TeHV identification, phylogenetic analysis and pathological characterization of the associated lesions, were performed. Our results revealed 1) the existence of at least two distinct TeHV3 genogroups apparently associated with different pathologies in tortoises and 2) the first evidence for a putative homologous recombination event having occurred in a chelonian herpesvirus. This novel information is not only fundamental for the genetic characterization of this virus but is also critical to lay the groundwork for an improved understanding of host-pathogen interactions in chelonians and contribute to tortoise conservation.

No MeSH data available.


Related in: MedlinePlus

Alignment and comparison of the partial amino acid sequence of the DNA polymerase protein of the TeHVs strains.The alignment of the partial amino acid sequences of the DNA polymerase protein shows unique differences between the 4 recognized TeHVs genotypes. All but one of the detected TeHVs strains had sequences identical to TeHV3, whereas one strain belonged to genotype 1. (The Genbank accession numbers for TeHVs reference strains were: TeHV1-AB047545.1, TeHV2-AY916792.1, TeHV3 (1976/96 = US1976/98)-DQ343881, TeHV4-GQ222415.1. The partial DNA polymerase amino acid sequences of the TeHVs strains detected in this study could not be deposited in Genbank because their length was below the minimum required to be accepted)
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pone.0134897.g003: Alignment and comparison of the partial amino acid sequence of the DNA polymerase protein of the TeHVs strains.The alignment of the partial amino acid sequences of the DNA polymerase protein shows unique differences between the 4 recognized TeHVs genotypes. All but one of the detected TeHVs strains had sequences identical to TeHV3, whereas one strain belonged to genotype 1. (The Genbank accession numbers for TeHVs reference strains were: TeHV1-AB047545.1, TeHV2-AY916792.1, TeHV3 (1976/96 = US1976/98)-DQ343881, TeHV4-GQ222415.1. The partial DNA polymerase amino acid sequences of the TeHVs strains detected in this study could not be deposited in Genbank because their length was below the minimum required to be accepted)

Mentions: Partial amplification of the DNApol gene from all the tortoises included in the study (N = 15) was carried out with consensus primers according to an established protocol [33]. The PCR products were consistent with the expected size (181nt) and the DNA sequences were translated into the predicted 60 aa long sequence (58 aa readable for strain CH5132/08). Fourteen out of the fifteen sequences shared 100% identity with the homologous sequence of other TeHV3 strains (DQ343881; TeHV3 1976/96 = US1976/98). The remaining strain (IT13/08) showed 100% identity with the homologous sequence of TeHV1 strains (AB047545.1). The aligned sequences along with those of TeHVs reference strains are shown in Fig 3.


A Genomic Approach to Unravel Host-Pathogen Interaction in Chelonians: The Example of Testudinid Herpesvirus 3.

Origgi FC, Tecilla M, Pilo P, Aloisio F, Otten P, Aguilar-Bultet L, Sattler U, Roccabianca P, Romero CH, Bloom DC, Jacobson ER - PLoS ONE (2015)

Alignment and comparison of the partial amino acid sequence of the DNA polymerase protein of the TeHVs strains.The alignment of the partial amino acid sequences of the DNA polymerase protein shows unique differences between the 4 recognized TeHVs genotypes. All but one of the detected TeHVs strains had sequences identical to TeHV3, whereas one strain belonged to genotype 1. (The Genbank accession numbers for TeHVs reference strains were: TeHV1-AB047545.1, TeHV2-AY916792.1, TeHV3 (1976/96 = US1976/98)-DQ343881, TeHV4-GQ222415.1. The partial DNA polymerase amino acid sequences of the TeHVs strains detected in this study could not be deposited in Genbank because their length was below the minimum required to be accepted)
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526542&req=5

pone.0134897.g003: Alignment and comparison of the partial amino acid sequence of the DNA polymerase protein of the TeHVs strains.The alignment of the partial amino acid sequences of the DNA polymerase protein shows unique differences between the 4 recognized TeHVs genotypes. All but one of the detected TeHVs strains had sequences identical to TeHV3, whereas one strain belonged to genotype 1. (The Genbank accession numbers for TeHVs reference strains were: TeHV1-AB047545.1, TeHV2-AY916792.1, TeHV3 (1976/96 = US1976/98)-DQ343881, TeHV4-GQ222415.1. The partial DNA polymerase amino acid sequences of the TeHVs strains detected in this study could not be deposited in Genbank because their length was below the minimum required to be accepted)
Mentions: Partial amplification of the DNApol gene from all the tortoises included in the study (N = 15) was carried out with consensus primers according to an established protocol [33]. The PCR products were consistent with the expected size (181nt) and the DNA sequences were translated into the predicted 60 aa long sequence (58 aa readable for strain CH5132/08). Fourteen out of the fifteen sequences shared 100% identity with the homologous sequence of other TeHV3 strains (DQ343881; TeHV3 1976/96 = US1976/98). The remaining strain (IT13/08) showed 100% identity with the homologous sequence of TeHV1 strains (AB047545.1). The aligned sequences along with those of TeHVs reference strains are shown in Fig 3.

Bottom Line: Consistently, the phylogenetic analysis positions TeHV3 among the Alphaherpesvirinae, closely associated with Chelonid herpesvirus 5, a Scutavirus.To exemplify the potential benefits of the novel genomic information provided by this first whole genome analysis, we selected the glycoprotein B (gB) gene, for detailed comparison among different TeHV3 isolates.Viral isolation, TeHV identification, phylogenetic analysis and pathological characterization of the associated lesions, were performed.

View Article: PubMed Central - PubMed

Affiliation: Centre for Fish and Wildlife Health (FIWI), Vetsuisse Faculty, University of Bern, Bern, Switzerland.

ABSTRACT
We report the first de novo sequence assembly and analysis of the genome of Testudinid herpesvirus 3 (TeHV3), one of the most pathogenic chelonian herpesviruses. The genome of TeHV3 is at least 150,080 nucleotides long, is arranged in a type D configuration and comprises at least 102 open reading frames extensively co-linear with those of Human herpesvirus 1. Consistently, the phylogenetic analysis positions TeHV3 among the Alphaherpesvirinae, closely associated with Chelonid herpesvirus 5, a Scutavirus. To date, there has been limited genetic characterization of TeHVs and a resolution beyond the genotype was not feasible because of the lack of informative DNA sequences. To exemplify the potential benefits of the novel genomic information provided by this first whole genome analysis, we selected the glycoprotein B (gB) gene, for detailed comparison among different TeHV3 isolates. The rationale for selecting gB is that it encodes for a well-conserved protein among herpesviruses but is coupled with a relevant antigenicity and is consequently prone to accumulate single nucleotide polymorphisms. These features were considered critical for an ideal phylogenetic marker to investigate the potential existence of distinct TeHV3 genogroups and their associated pathology. Fifteen captive tortoises presumptively diagnosed to be infected with TeHVs or carrying compatible lesions on the basis of either the presence of intranuclear inclusions (presumptively infected) and/or diphtheronecrotic stomatitis-glossitis or pneumonia (compatible lesions) were selected for the study. Viral isolation, TeHV identification, phylogenetic analysis and pathological characterization of the associated lesions, were performed. Our results revealed 1) the existence of at least two distinct TeHV3 genogroups apparently associated with different pathologies in tortoises and 2) the first evidence for a putative homologous recombination event having occurred in a chelonian herpesvirus. This novel information is not only fundamental for the genetic characterization of this virus but is also critical to lay the groundwork for an improved understanding of host-pathogen interactions in chelonians and contribute to tortoise conservation.

No MeSH data available.


Related in: MedlinePlus