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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

TeHV3 and ChHV5 genome comparison.The graphical comparison between TeHV3 and ChHV5 genomes obtained with the EasyFig1 software is shown in the figure. The genomes of TeHV3 and ChHV5 are depicted in red, with a black backbone. Similar regions are connected with gray (low) to black (high) (direct sequences) and orange (low) to red (high) (inverted sequences) bars. Green, blue and red bars highlighting the US and UL regions and of the inverted repeats (terminal and internal) of each genome, respectively are also shown. Letters A, B, C, D, E and F correspond to regions of the genomes that show no similarities within the conserved UL block.
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pone.0134897.g002: TeHV3 and ChHV5 genome comparison.The graphical comparison between TeHV3 and ChHV5 genomes obtained with the EasyFig1 software is shown in the figure. The genomes of TeHV3 and ChHV5 are depicted in red, with a black backbone. Similar regions are connected with gray (low) to black (high) (direct sequences) and orange (low) to red (high) (inverted sequences) bars. Green, blue and red bars highlighting the US and UL regions and of the inverted repeats (terminal and internal) of each genome, respectively are also shown. Letters A, B, C, D, E and F correspond to regions of the genomes that show no similarities within the conserved UL block.

Mentions: The predicted UL region comprises at least 79 ORFs; 37FW, 42RV, with 35 partially overlapping. Sixty-two of them showed variable degrees of similarity with known herpesvirus genes, ranging from 38 to 79% for the UL47 (Psittacid herpesvirus 1) and UL 45 (Ateline herpesvirus 3) homologues, respectively. The remaining ORFs could not be associated unambiguously to a known herpesvirus gene (Table 4 and Figs 1 and 2).


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)

TeHV3 and ChHV5 genome comparison.The graphical comparison between TeHV3 and ChHV5 genomes obtained with the EasyFig1 software is shown in the figure. The genomes of TeHV3 and ChHV5 are depicted in red, with a black backbone. Similar regions are connected with gray (low) to black (high) (direct sequences) and orange (low) to red (high) (inverted sequences) bars. Green, blue and red bars highlighting the US and UL regions and of the inverted repeats (terminal and internal) of each genome, respectively are also shown. Letters A, B, C, D, E and F correspond to regions of the genomes that show no similarities within the conserved UL block.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0134897.g002: TeHV3 and ChHV5 genome comparison.The graphical comparison between TeHV3 and ChHV5 genomes obtained with the EasyFig1 software is shown in the figure. The genomes of TeHV3 and ChHV5 are depicted in red, with a black backbone. Similar regions are connected with gray (low) to black (high) (direct sequences) and orange (low) to red (high) (inverted sequences) bars. Green, blue and red bars highlighting the US and UL regions and of the inverted repeats (terminal and internal) of each genome, respectively are also shown. Letters A, B, C, D, E and F correspond to regions of the genomes that show no similarities within the conserved UL block.
Mentions: The predicted UL region comprises at least 79 ORFs; 37FW, 42RV, with 35 partially overlapping. Sixty-two of them showed variable degrees of similarity with known herpesvirus genes, ranging from 38 to 79% for the UL47 (Psittacid herpesvirus 1) and UL 45 (Ateline herpesvirus 3) homologues, respectively. The remaining ORFs could not be associated unambiguously to a known herpesvirus gene (Table 4 and Figs 1 and 2).

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