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De Novo sequencing and transcriptome analysis for Tetramorium bicarinatum: a comprehensive venom gland transcriptome analysis from an ant species.

Bouzid W, Verdenaud M, Klopp C, Ducancel F, Noirot C, Vétillard A - BMC Genomics (2014)

Bottom Line: Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue.To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal.In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

View Article: PubMed Central - PubMed

Affiliation: Venoms and Biological Activities Laboratory, EA 4357, PRES-University of Toulouse, Jean-François Champollion University Center, Albi, France. angelique.vetillard@univ-jfc.fr.

ABSTRACT

Background: Arthropod venoms are invaluable sources of bioactive substances with biotechnological application. The limited availability of some venoms, such as those from ants, has restricted the knowledge about the composition and the potential that these biomolecules could represent. In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput approach using Illumina technology has been applied to analyze the genes expressed in active venom glands of this ant species.

Results: A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%), followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue. Finally, about 40% of the generated contigs have no hits in the databases with 25% of the predicted peptides bearing signal peptide emphasizing the potential of the investigation of these sequences as source of new molecules. Among these contigs, six putative novel peptides that show homologies with previously identified antimicrobial peptides were identified.

Conclusions: To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal. In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

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Related in: MedlinePlus

Amino acid sequence alignment of representative of pilosulins and pilosulin-like from different ant species. The sequence of bicarinalin/pilosulin-like (Tb34317) from T. bicarinatum was aligned with sequences of the pilosulin family from Myrmecia banksi [GenBank: Q68Y23.1 and BAF95069] and Myrmecia pilosula [GenBank: AAB50883]. JZ168521–JZ168537 refer to GenBank accession numbers of transcripts from T. bicarinatum contig recovered from our previous study [13]. Amino acids that are identical in all or the majority of the sequences are highlighted with different shades of blue that represent their degree of conservation. The active peptide sequence of bicarinalin identified in a previous study [21] is indicated by a red box. Putative signal peptide is underlined.
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Fig4: Amino acid sequence alignment of representative of pilosulins and pilosulin-like from different ant species. The sequence of bicarinalin/pilosulin-like (Tb34317) from T. bicarinatum was aligned with sequences of the pilosulin family from Myrmecia banksi [GenBank: Q68Y23.1 and BAF95069] and Myrmecia pilosula [GenBank: AAB50883]. JZ168521–JZ168537 refer to GenBank accession numbers of transcripts from T. bicarinatum contig recovered from our previous study [13]. Amino acids that are identical in all or the majority of the sequences are highlighted with different shades of blue that represent their degree of conservation. The active peptide sequence of bicarinalin identified in a previous study [21] is indicated by a red box. Putative signal peptide is underlined.

Mentions: Members of the pilosulin-like peptides were also identified in our library. The status and features of these peptides have been discussed in our previous work where we showed that different isoforms and families of pilosulin-like sequences occur in T. bicarinatum[13]. Recently, two short peptides (named bicarinalin and peptide2) from T. bicarinatum venom have been characterized by de novo sequencing using mass spectrometry and Edman degradation [21, 22]. The authors show that these mature peptides, identified among the most abundant in the venom of this ant species have no homolog in the public database. In our study, we have recovered these peptides and identified their cDNA sequences (Additional file 2: Table S1). However, when we blast the whole peptide sequences predicted from the cDNA, we found that their leader sequence and propeptide have homologies with those of pilosulin sequences (Figure 4). Moreover, the bicarinalin has been shown to have a potent and broad antibacterial activity as much as pilosulins [21]. Hence, it seems that the bicarinalin and peptide2 or the pilosulin-like forms from T. bicarinatum have the same features as some bioactive peptides in that they have a conserved secretory leader and propeptide sequence but differ greatly in their mature peptide [23, 24]. This fact has been attributed to recombination as a toxin diversity-generating mechanism giving individualistic utilization of specific isoforms [25].Figure 4


De Novo sequencing and transcriptome analysis for Tetramorium bicarinatum: a comprehensive venom gland transcriptome analysis from an ant species.

Bouzid W, Verdenaud M, Klopp C, Ducancel F, Noirot C, Vétillard A - BMC Genomics (2014)

Amino acid sequence alignment of representative of pilosulins and pilosulin-like from different ant species. The sequence of bicarinalin/pilosulin-like (Tb34317) from T. bicarinatum was aligned with sequences of the pilosulin family from Myrmecia banksi [GenBank: Q68Y23.1 and BAF95069] and Myrmecia pilosula [GenBank: AAB50883]. JZ168521–JZ168537 refer to GenBank accession numbers of transcripts from T. bicarinatum contig recovered from our previous study [13]. Amino acids that are identical in all or the majority of the sequences are highlighted with different shades of blue that represent their degree of conservation. The active peptide sequence of bicarinalin identified in a previous study [21] is indicated by a red box. Putative signal peptide is underlined.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4256838&req=5

Fig4: Amino acid sequence alignment of representative of pilosulins and pilosulin-like from different ant species. The sequence of bicarinalin/pilosulin-like (Tb34317) from T. bicarinatum was aligned with sequences of the pilosulin family from Myrmecia banksi [GenBank: Q68Y23.1 and BAF95069] and Myrmecia pilosula [GenBank: AAB50883]. JZ168521–JZ168537 refer to GenBank accession numbers of transcripts from T. bicarinatum contig recovered from our previous study [13]. Amino acids that are identical in all or the majority of the sequences are highlighted with different shades of blue that represent their degree of conservation. The active peptide sequence of bicarinalin identified in a previous study [21] is indicated by a red box. Putative signal peptide is underlined.
Mentions: Members of the pilosulin-like peptides were also identified in our library. The status and features of these peptides have been discussed in our previous work where we showed that different isoforms and families of pilosulin-like sequences occur in T. bicarinatum[13]. Recently, two short peptides (named bicarinalin and peptide2) from T. bicarinatum venom have been characterized by de novo sequencing using mass spectrometry and Edman degradation [21, 22]. The authors show that these mature peptides, identified among the most abundant in the venom of this ant species have no homolog in the public database. In our study, we have recovered these peptides and identified their cDNA sequences (Additional file 2: Table S1). However, when we blast the whole peptide sequences predicted from the cDNA, we found that their leader sequence and propeptide have homologies with those of pilosulin sequences (Figure 4). Moreover, the bicarinalin has been shown to have a potent and broad antibacterial activity as much as pilosulins [21]. Hence, it seems that the bicarinalin and peptide2 or the pilosulin-like forms from T. bicarinatum have the same features as some bioactive peptides in that they have a conserved secretory leader and propeptide sequence but differ greatly in their mature peptide [23, 24]. This fact has been attributed to recombination as a toxin diversity-generating mechanism giving individualistic utilization of specific isoforms [25].Figure 4

Bottom Line: Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue.To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal.In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

View Article: PubMed Central - PubMed

Affiliation: Venoms and Biological Activities Laboratory, EA 4357, PRES-University of Toulouse, Jean-François Champollion University Center, Albi, France. angelique.vetillard@univ-jfc.fr.

ABSTRACT

Background: Arthropod venoms are invaluable sources of bioactive substances with biotechnological application. The limited availability of some venoms, such as those from ants, has restricted the knowledge about the composition and the potential that these biomolecules could represent. In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput approach using Illumina technology has been applied to analyze the genes expressed in active venom glands of this ant species.

Results: A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%), followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).The non-toxin transcripts were mainly represented by contigs involved in protein folding and translation, consistent with the protein-secretory function of the venom gland tissue. Finally, about 40% of the generated contigs have no hits in the databases with 25% of the predicted peptides bearing signal peptide emphasizing the potential of the investigation of these sequences as source of new molecules. Among these contigs, six putative novel peptides that show homologies with previously identified antimicrobial peptides were identified.

Conclusions: To the best of our knowledge, this work reports the first large-scale analysis of genes transcribed by the venomous gland of the ant species T. bicarinatum and helps with the identification of Hymenoptera toxin arsenal. In addition, results from this study demonstrate that de novo transcriptome assembly allows useful venom gene expression analysis in a species lacking a genome sequence database.

Show MeSH
Related in: MedlinePlus