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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

Glycoprotein B-based phylogenetic analysis.Maximum likelihood tree inferred from the partial aa sequence of the gB of the 15 TeHVs strains investigated in this study and of reference strains of other ChHV (ChHV5, -6). Gallid herpesvirus 1 (GaHV1) was included as outgroup. Bootstrap values from 500 iterations are shown. This analysis reveals the existence of at least two distinct genogroups within the TeHV3 genotype (A-green boxed and B-red boxed). A third putative genogroup (C-blue boxed) composed of a single strain is also observed. A TeHV1 strain (IT13/08) clusters within the A genogroup of the TeHV3 genotype. Clear separation of the TeHV3 genogroups from the sequences of other two chelonian herpesviruses (ChHV5 and ChHV6) is observed. (Genbank accession numbers: CH1970/02-KP979727, CH1690/03-KP979726, CH1611/07-KP979721, CH2360/06-KP979725, CH2053/01-KP979723, CH5132/08-KP979729, CH7204/00-KP979719, CH6883/03-KP979730, CH2313/07-KP979722, CH3429/01-KP979720, CH1458/12-KP979718, US1976/98-KP979717, IT186/12-KP979728, IT191/12-KP979716, IT13/08-KP979724, ChHV5-AAU93326, ChHV6-AAM95776, GaHV1-YP_182356).
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pone.0134897.g009: Glycoprotein B-based phylogenetic analysis.Maximum likelihood tree inferred from the partial aa sequence of the gB of the 15 TeHVs strains investigated in this study and of reference strains of other ChHV (ChHV5, -6). Gallid herpesvirus 1 (GaHV1) was included as outgroup. Bootstrap values from 500 iterations are shown. This analysis reveals the existence of at least two distinct genogroups within the TeHV3 genotype (A-green boxed and B-red boxed). A third putative genogroup (C-blue boxed) composed of a single strain is also observed. A TeHV1 strain (IT13/08) clusters within the A genogroup of the TeHV3 genotype. Clear separation of the TeHV3 genogroups from the sequences of other two chelonian herpesviruses (ChHV5 and ChHV6) is observed. (Genbank accession numbers: CH1970/02-KP979727, CH1690/03-KP979726, CH1611/07-KP979721, CH2360/06-KP979725, CH2053/01-KP979723, CH5132/08-KP979729, CH7204/00-KP979719, CH6883/03-KP979730, CH2313/07-KP979722, CH3429/01-KP979720, CH1458/12-KP979718, US1976/98-KP979717, IT186/12-KP979728, IT191/12-KP979716, IT13/08-KP979724, ChHV5-AAU93326, ChHV6-AAM95776, GaHV1-YP_182356).

Mentions: The phylogenetic analysis carried out on the partial aa sequences of the DNA pol (Type 1 analysis) revealed the presence of 14 strains clustering within TeHV3 and one within TeHV1 genotypes, respectively (Fig 8). In contrast, the phylogenetic analysis based on the partial aa sequence of the gB protein (Type 1 analysis) revealed the existence of two distinct TeHV3 genogroups supported by significant bootstrap values (Fig 9). Additionally, the strain CH3429/01 clustered alone in an intermediate position between the two main TeHV3 genogroups paralleling the findings of the gB sequencing described above. The partial gB aa sequence of the single TeHV1 strain, IT13/08, clustered together with the TeHV3 genogroup A strains (Fig 9). Overlapping results were obtained independently from the alignment software used.


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)

Glycoprotein B-based phylogenetic analysis.Maximum likelihood tree inferred from the partial aa sequence of the gB of the 15 TeHVs strains investigated in this study and of reference strains of other ChHV (ChHV5, -6). Gallid herpesvirus 1 (GaHV1) was included as outgroup. Bootstrap values from 500 iterations are shown. This analysis reveals the existence of at least two distinct genogroups within the TeHV3 genotype (A-green boxed and B-red boxed). A third putative genogroup (C-blue boxed) composed of a single strain is also observed. A TeHV1 strain (IT13/08) clusters within the A genogroup of the TeHV3 genotype. Clear separation of the TeHV3 genogroups from the sequences of other two chelonian herpesviruses (ChHV5 and ChHV6) is observed. (Genbank accession numbers: CH1970/02-KP979727, CH1690/03-KP979726, CH1611/07-KP979721, CH2360/06-KP979725, CH2053/01-KP979723, CH5132/08-KP979729, CH7204/00-KP979719, CH6883/03-KP979730, CH2313/07-KP979722, CH3429/01-KP979720, CH1458/12-KP979718, US1976/98-KP979717, IT186/12-KP979728, IT191/12-KP979716, IT13/08-KP979724, ChHV5-AAU93326, ChHV6-AAM95776, GaHV1-YP_182356).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4526542&req=5

pone.0134897.g009: Glycoprotein B-based phylogenetic analysis.Maximum likelihood tree inferred from the partial aa sequence of the gB of the 15 TeHVs strains investigated in this study and of reference strains of other ChHV (ChHV5, -6). Gallid herpesvirus 1 (GaHV1) was included as outgroup. Bootstrap values from 500 iterations are shown. This analysis reveals the existence of at least two distinct genogroups within the TeHV3 genotype (A-green boxed and B-red boxed). A third putative genogroup (C-blue boxed) composed of a single strain is also observed. A TeHV1 strain (IT13/08) clusters within the A genogroup of the TeHV3 genotype. Clear separation of the TeHV3 genogroups from the sequences of other two chelonian herpesviruses (ChHV5 and ChHV6) is observed. (Genbank accession numbers: CH1970/02-KP979727, CH1690/03-KP979726, CH1611/07-KP979721, CH2360/06-KP979725, CH2053/01-KP979723, CH5132/08-KP979729, CH7204/00-KP979719, CH6883/03-KP979730, CH2313/07-KP979722, CH3429/01-KP979720, CH1458/12-KP979718, US1976/98-KP979717, IT186/12-KP979728, IT191/12-KP979716, IT13/08-KP979724, ChHV5-AAU93326, ChHV6-AAM95776, GaHV1-YP_182356).
Mentions: The phylogenetic analysis carried out on the partial aa sequences of the DNA pol (Type 1 analysis) revealed the presence of 14 strains clustering within TeHV3 and one within TeHV1 genotypes, respectively (Fig 8). In contrast, the phylogenetic analysis based on the partial aa sequence of the gB protein (Type 1 analysis) revealed the existence of two distinct TeHV3 genogroups supported by significant bootstrap values (Fig 9). Additionally, the strain CH3429/01 clustered alone in an intermediate position between the two main TeHV3 genogroups paralleling the findings of the gB sequencing described above. The partial gB aa sequence of the single TeHV1 strain, IT13/08, clustered together with the TeHV3 genogroup A strains (Fig 9). Overlapping results were obtained independently from the alignment software used.

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