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Entiauspe-Neto OM, Nachtigall PG, Borges-Martins M, Junqueira-de-Azevedo ILM, Grazziotin FG. Highly conserved and extremely variable: The paradoxical pattern of toxin expression revealed by comparative venom-gland transcriptomics of Phalotris (Serpentes: Dipsadidae). Toxicon 2024; 244:107740. [PMID: 38705487 DOI: 10.1016/j.toxicon.2024.107740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/11/2024] [Accepted: 04/27/2024] [Indexed: 05/07/2024]
Abstract
Although non-front fanged snakes account for almost two-thirds of snake diversity, most studies on venom composition and evolution focus exclusively on front-fanged species, which comprise most of the clinically relevant accidents. Comprehensive reports on venom composition of non-front fanged snakes are still scarce for several groups. In this study, we address such shortage of knowledge by providing new insights about the venom composition among species of Phalotris, a poorly studied Neotropical dipsadid genus. Phalotris are known for their specialized venom delivery system and toxic venoms, which can cause life-threatening accidents in humans. We evaluate the venom-gland transcriptome of Phalotris, comparing the following three South American species: P. reticulatus for the Araucaria Pine forests, P. lemniscatus for the Pampa grasslands, and P. mertensi for the Brazilian Cerrado. Our results indicate similar venom profiles, in which they share a high expression level of Kunitz-type inhibitors (KUNZ). On the other hand, comparative analyses revealed substantial differences in the expression levels of C-type lectins (CTL) and snake venom metalloproteinases (SVMP). The diverse set of SVMP and CTL isoforms shows signals of positive selection, and we also identified truncated forms of type III SVMPs, which resemble type II and type I SVMPs of viperids. Additionally, we identified a CNP precursor hosting a proline-rich region containing a BPP motif resembling those commonly detected in viperid venoms with hypotensive activity. Altogether, our results suggest an evolutionary history favoring high expression levels of few KUNZ isoforms in Phalotris venoms, contrasting with a highly diverse set of SVMP and CTL isoforms. Such diversity can be comparable with the venom variability observed in some viperids. Our findings highlight the extreme phenotypic diversity of non-front fanged snakes and the importance to allocate greater effort to study neglected groups of Colubroidea.
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Affiliation(s)
- Omar M Entiauspe-Neto
- Laboratório de Coleções Zoológicas, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil; Programa de Pós-graduação em Biologia Animal, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, CEP 91501-970, Porto Alegre, RS, Brazil.
| | - Pedro G Nachtigall
- Laboratório de Toxinologia Aplicada, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil
| | - Márcio Borges-Martins
- Programa de Pós-graduação em Biologia Animal, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, CEP 91501-970, Porto Alegre, RS, Brazil
| | | | - Felipe G Grazziotin
- Laboratório de Coleções Zoológicas, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil
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2
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Sonoda GG, Tobaruela EDC, Norenburg J, Fabi JP, Andrade SCS. Venomous Noodles: The Evolution of Toxins in Nemertea through Positive Selection and Gene Duplication. Toxins (Basel) 2023; 15:650. [PMID: 37999513 PMCID: PMC10674772 DOI: 10.3390/toxins15110650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 11/25/2023] Open
Abstract
Some, probably most and perhaps all, members of the phylum Nemertea are poisonous, documented so far from marine and benthic specimens. Although the toxicity of these animals has been long known, systematic studies on the characterization of toxins, mechanisms of toxicity, and toxin evolution for this group are scarce. Here, we present the first investigation of the molecular evolution of toxins in Nemertea. Using a proteo-transcriptomic approach, we described toxins in the body and poisonous mucus of the pilidiophoran Lineus sanguineus and the hoplonemertean Nemertopsis pamelaroeae. Using these new and publicly available transcriptomes, we investigated the molecular evolution of six selected toxin gene families. In addition, we also characterized in silico the toxin genes found in the interstitial hoplonemertean, Ototyphlonemertes erneba, a meiofaunal taxa. We successfully identified over 200 toxin transcripts in each of these species. Evidence of positive selection and gene duplication was observed in all investigated toxin genes. We hypothesized that the increased rates of gene duplications observed for Pilidiophora could be involved with the expansion of toxin genes. Studies concerning the natural history of Nemertea are still needed to understand the evolution of their toxins. Nevertheless, our results show evolutionary mechanisms similar to other venomous groups.
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Affiliation(s)
- Gabriel Gonzalez Sonoda
- Departamento de Genética e Biologia Evolutiva, IB-Universidade de São Paulo, São Paulo 05508-090, Brazil;
- Instituto Butantan, São Paulo 05503-900, Brazil
| | - Eric de Castro Tobaruela
- Faculdade de Ciências Farmacêuticas, Food Research Center (FoRC), Universidade de São Paulo, São Paulo 05508-080, Brazil; (E.d.C.T.); (J.P.F.)
| | | | - João Paulo Fabi
- Faculdade de Ciências Farmacêuticas, Food Research Center (FoRC), Universidade de São Paulo, São Paulo 05508-080, Brazil; (E.d.C.T.); (J.P.F.)
| | - Sónia C. S. Andrade
- Departamento de Genética e Biologia Evolutiva, IB-Universidade de São Paulo, São Paulo 05508-090, Brazil;
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Srodawa K, Cerda PA, Davis Rabosky AR, Crowe-Riddell JM. Evolution of Three-Finger Toxin Genes in Neotropical Colubrine Snakes (Colubridae). Toxins (Basel) 2023; 15:523. [PMID: 37755949 PMCID: PMC10534312 DOI: 10.3390/toxins15090523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/16/2023] [Accepted: 08/23/2023] [Indexed: 09/28/2023] Open
Abstract
Snake venom research has historically focused on front-fanged species (Viperidae and Elapidae), limiting our knowledge of venom evolution in rear-fanged snakes across their ecologically diverse phylogeny. Three-finger toxins (3FTxs) are a known neurotoxic component in the venoms of some rear-fanged snakes (Colubridae: Colubrinae), but it is unclear how prevalent 3FTxs are both in expression within venom glands and more broadly among colubrine species. Here, we used a transcriptomic approach to characterize the venom expression profiles of four species of colubrine snakes from the Neotropics that were dominated by 3FTx expression (in the genera Chironius, Oxybelis, Rhinobothryum, and Spilotes). By reconstructing the gene trees of 3FTxs, we found evidence of putative novel heterodimers in the sequences of Chironius multiventris and Oxybelis aeneus, revealing an instance of parallel evolution of this structural change in 3FTxs among rear-fanged colubrine snakes. We also found positive selection at sites within structural loops or "fingers" of 3FTxs, indicating these areas may be key binding sites that interact with prey target molecules. Overall, our results highlight the importance of exploring the venoms of understudied species in reconstructing the full evolutionary history of toxins across the tree of life.
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Affiliation(s)
- Kristy Srodawa
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (K.S.); (A.R.D.R.); (J.M.C.-R.)
- Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter A. Cerda
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (K.S.); (A.R.D.R.); (J.M.C.-R.)
- Museum of Zoology, University of Michigan, Ann Arbor, MI 48108, USA
| | - Alison R. Davis Rabosky
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (K.S.); (A.R.D.R.); (J.M.C.-R.)
- Museum of Zoology, University of Michigan, Ann Arbor, MI 48108, USA
| | - Jenna M. Crowe-Riddell
- Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; (K.S.); (A.R.D.R.); (J.M.C.-R.)
- Museum of Zoology, University of Michigan, Ann Arbor, MI 48108, USA
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
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4
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Tioyama EC, Bayona-Serrano JD, Portes-Junior JA, Nachtigall PG, de Souza VC, Beraldo-Neto E, Grazziotin FG, Junqueira-de-Azevedo ILM, Moura-da-Silva AM, Freitas-de-Sousa LA. The Venom Composition of the Snake Tribe Philodryadini: 'Omic' Techniques Reveal Intergeneric Variability among South American Racers. Toxins (Basel) 2023; 15:415. [PMID: 37505684 PMCID: PMC10467154 DOI: 10.3390/toxins15070415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 05/31/2023] [Accepted: 06/03/2023] [Indexed: 07/29/2023] Open
Abstract
Snakes of the Philodryadini tribe are included in the Dipsadidae family, which is a diverse group of rear-fanged snakes widespread in different ecological conditions, including habitats and diet. However, little is known about the composition and effects of their venoms despite their relevance for understanding the evolution of these snakes or even their impact on the occasional cases of human envenoming. In this study, we integrated venom gland transcriptomics, venom proteomics and functional assays to characterize the venoms from eight species of the Philodryadini tribe, which includes the genus Philodryas, Chlorosoma and Xenoxybelis. The most abundant components identified in the venoms were snake venom metalloproteinases (SVMPs), cysteine-rich secretory proteins (CRISPs), C-type lectins (CTLs), snake endogenous matrix metalloproteinases type 9 (seMMP-9) and snake venom serinoproteinases (SVSPs). These protein families showed a variable expression profile in each genus. SVMPs were the most abundant components in Philodryas, while seMMP-9 and CRISPs were the most expressed in Chlorosoma and Xenoxybelis, respectively. Lineage-specific differences in venom composition were also observed among Philodryas species, whereas P. olfersii presented the highest amount of SVSPs and P. agassizii was the only species to express significant amounts of 3FTx. The variability observed in venom composition was confirmed by the venom functional assays. Philodryas species presented the highest SVMP activity, whereas Chlorosoma species showed higher levels of gelatin activity, which may correlate to the seMMP-9 enzymes. The variability observed in the composition of these venoms may be related to the tribe phylogeny and influenced by their diets. In the presented study, we expanded the set of venomics studies of the Philodryadini tribe, which paves new roads for further studies on the evolution and ecology of Dipsadidae snakes.
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Affiliation(s)
- Emilly Campos Tioyama
- Programa de Pós-Graduação em Ciências-Toxinologia, Escola Superior do Instituto Butantan, São Paulo 05508-210, Brazil; (E.C.T.); (J.D.B.-S.)
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil; (J.A.P.-J.); (A.M.M.-d.-S.)
| | - Juan David Bayona-Serrano
- Programa de Pós-Graduação em Ciências-Toxinologia, Escola Superior do Instituto Butantan, São Paulo 05508-210, Brazil; (E.C.T.); (J.D.B.-S.)
- Laboratório de Toxinologia Aplicada, Instituto Butantan, São Paulo 05503-900, Brazil; (P.G.N.); (V.C.d.S.); (I.L.M.J.-d.-A.)
| | - José A. Portes-Junior
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil; (J.A.P.-J.); (A.M.M.-d.-S.)
| | - Pedro Gabriel Nachtigall
- Laboratório de Toxinologia Aplicada, Instituto Butantan, São Paulo 05503-900, Brazil; (P.G.N.); (V.C.d.S.); (I.L.M.J.-d.-A.)
| | - Vinicius Carius de Souza
- Laboratório de Toxinologia Aplicada, Instituto Butantan, São Paulo 05503-900, Brazil; (P.G.N.); (V.C.d.S.); (I.L.M.J.-d.-A.)
| | - Emidio Beraldo-Neto
- Laboratório de Bioquímica e Biofísica, Instituto Butantan, São Paulo 05503-900, Brazil;
| | | | | | - Ana Maria Moura-da-Silva
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil; (J.A.P.-J.); (A.M.M.-d.-S.)
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5
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Trevine VC, Grazziotin FG, Giraudo A, Sallesbery‐Pinchera N, Vianna JA, Zaher H. The systematics of Tachymenini (Serpentes, Dipsadidae): An updated classification based on molecular and morphological evidence. ZOOL SCR 2022. [DOI: 10.1111/zsc.12565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Vivian C. Trevine
- Laboratório de Coleções Zoológicas Instituto Butantan São Paulo Brazil
- Programa de Pós‐Graduação de Zoologia, Insituto de Biociências Universidade de São Paulo São Paulo Brazil
| | | | - Alejandro Giraudo
- Instituto Nacional de Limnología (CONICET – UNL) Ciudad Universitaria Santa Fe Argentina
- Facultad de Humanidades y Ciencias (FHUC – UNL) Ciudad Universitaria Santa Fe Argentina
| | - Nicole Sallesbery‐Pinchera
- Escuela Medicina Veterinaria, Facultad Ecología y Recursos Naturales Universidad Andrés Bello Santiago Chile
| | - Juliana A. Vianna
- Millennium Institute Center for Genome Regulation (CRG), Departamento de Ecosistemas y Medio Ambiente Pontificia Universidad Católica de Chile Santiago Chile
| | - Hussam Zaher
- Laboratório de Herpetologia, Museu de Zoologia da Universidade de São Paulo São Paulo Brazil
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6
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Venom Variation of Neonate and Adult Chinese Cobras in Captivity Concerning Their Foraging Strategies. Toxins (Basel) 2022; 14:toxins14090598. [PMID: 36136536 PMCID: PMC9501182 DOI: 10.3390/toxins14090598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 11/22/2022] Open
Abstract
The venom and transcriptome profile of the captive Chinese cobra (Naja atra) is not characterized until now. Here, LC-MS/MS and illumine technology were used to unveil the venom and trascriptome of neonates and adults N. atra specimens. In captive Chinese cobra, 98 co-existing transcripts for venom-related proteins was contained. A total of 127 proteins belong to 21 protein families were found in the profile of venom. The main components of snake venom were three finger toxins (3-FTx), snake venom metalloproteinase (SVMP), cysteine-rich secretory protein (CRISP), cobra venom factor (CVF), and phosphodiesterase (PDE). During the ontogenesis of captive Chinese cobra, the rearrangement of snake venom composition occurred and with obscure gender difference. CVF, 3-FTx, PDE, phospholipase A2 (PLA2) in adults were more abundant than neonates, while SVMP and CRISP in the neonates was richer than the adults. Ontogenetic changes in the proteome of Chinese cobra venom reveals different strategies for handling prey. The levels of different types of toxin families were dramatically altered in the wild and captive specimens. Therefore, we speculate that the captive process could reshape the snake venom composition vigorously. The clear comprehension of the composition of Chinese cobra venom facilitates the understanding of the mechanism of snakebite intoxication and guides the preparation and administration of traditional antivenom and next-generation drugs for snakebite.
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7
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Divergent Specialization of Simple Venom Gene Profiles among Rear-Fanged Snake Genera ( Helicops and Leptodeira, Dipsadinae, Colubridae). Toxins (Basel) 2022; 14:toxins14070489. [PMID: 35878227 PMCID: PMC9319703 DOI: 10.3390/toxins14070489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023] Open
Abstract
Many venomous animals express toxins that show extraordinary levels of variation both within and among species. In snakes, most studies of venom variation focus on front-fanged species in the families Viperidae and Elapidae, even though rear-fanged snakes in other families vary along the same ecological axes important to venom evolution. Here we characterized venom gland transcriptomes from 19 snakes across two dipsadine rear-fanged genera (Leptodeira and Helicops, Colubridae) and two front-fanged genera (Bothrops, Viperidae; Micrurus, Elapidae). We compared patterns of composition, variation, and diversity in venom transcripts within and among all four genera. Venom gland transcriptomes of rear-fanged Helicops and Leptodeira and front-fanged Micrurus are each dominated by expression of single toxin families (C-type lectins, snake venom metalloproteinase, and phospholipase A2, respectively), unlike highly diverse front-fanged Bothrops venoms. In addition, expression patterns of congeners are much more similar to each other than they are to species from other genera. These results illustrate the repeatability of simple venom profiles in rear-fanged snakes and the potential for relatively constrained venom composition within genera.
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8
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Abstract
The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.
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Affiliation(s)
- Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, 501 20th St., CB 92, Greeley, CO 80639-0017, USA
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9
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Schramer TD, Rautsaw RM, Bayona-Serrano JD, Nystrom GS, West TR, Ortiz-Medina JA, Sabido-Alpuche B, Meneses-Millán M, Borja M, Junqueira-de-Azevedo ILM, Rokyta DR, Parkinson CL. An integrative view of the toxic potential of Conophis lineatus (Dipsadidae: Xenodontinae), a medically relevant rear-fanged snake. Toxicon 2021; 205:38-52. [PMID: 34793822 DOI: 10.1016/j.toxicon.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/25/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Abstract
Most traditional research on snake venoms has focused on front-fanged snake families (Viperidae, Elapidae, and Atractaspididae). However, venom is now generally accepted as being a much more broadly possessed trait within snakes, including species traditionally considered harmless. Unfortunately, due to historical inertia and methodological challenges, the toxin repertoires of non-front-fanged snake families (e.g., Colubridae, Dipsadidae, and Natricidae) have been heavily neglected despite the knowledge of numerous species capable of inflicting medically relevant envenomations. Integrating proteomic data for validation, we perform a de novo assembly and analysis of the Duvernoy's venom gland transcriptome of the Central American Road Guarder (Dipsadidae: Xenodontinae: Conophis lineatus), a species known for its potent bite. We identified 28 putative toxin transcripts from 13 toxin families in the Duvernoy's venom gland transcriptome, comprising 63.7% of total transcriptome expression. In addition to ubiquitous snake toxin families, we proteomically confirmed several atypical venom components. The most highly expressed toxins (55.6% of total toxin expression) were recently described snake venom matrix metalloproteases (svMMPs), with 48.0% of svMMP expression contributable to a novel svMMP isoform. We investigate the evolution of the new svMMP isoform in the context of rear-fanged snakes using phylogenetics. Finally, we examine the morphology of the venom apparatus using μCT and explore how the venom relates to autecology and the highly hemorrhagic effects seen in human envenomations. Importantly, we provide the most complete venom characterization of this medically relevant snake species to date, producing insights into the effects and evolution of its venom, and point to future research directions to better understand the venoms of 'harmless' non-front-fanged snakes.
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Affiliation(s)
- Tristan D Schramer
- Department of Biological Sciences, Clemson University, Clemson, SC, USA.
| | - Rhett M Rautsaw
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | | | - Gunnar S Nystrom
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Taylor R West
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Javier A Ortiz-Medina
- Departamento de Sistemática y Ecología Acuática, El Colegio de La Frontera Sur, Unidad Chetumal, Chetumal, Quintana Roo, Mexico; Unidad de Manejo para La Conservación de La Vida Silvestre, Tsáab Kaan, Baca, Yucatán, Mexico; HERP.MX A.C., Villa de Álvarez, Colima, Mexico
| | - Bianca Sabido-Alpuche
- Unidad de Manejo para La Conservación de La Vida Silvestre, Tsáab Kaan, Baca, Yucatán, Mexico
| | - Marcos Meneses-Millán
- Unidad de Manejo para La Conservación de La Vida Silvestre, Tsáab Kaan, Baca, Yucatán, Mexico
| | - Miguel Borja
- Facultad de Ciencias Biológicas, Universidad Juárez Del Estado de Durango, Gómez Palacio, Durango, Mexico
| | - Inácio L M Junqueira-de-Azevedo
- Laboratório de Toxinologia Aplicada, Instituto Butantan, São Paulo, Brazil; Center of Toxins, Immune-Response and Cell Signaling (CeTICS), São Paulo, Brazil
| | - Darin R Rokyta
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Christopher L Parkinson
- Department of Biological Sciences, Clemson University, Clemson, SC, USA; Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC, USA.
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10
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Almeida DD, Viala VL, Nachtigall PG, Broe M, Gibbs HL, Serrano SMDT, Moura-da-Silva AM, Ho PL, Nishiyama-Jr MY, Junqueira-de-Azevedo ILM. Tracking the recruitment and evolution of snake toxins using the evolutionary context provided by the Bothrops jararaca genome. Proc Natl Acad Sci U S A 2021; 118:e2015159118. [PMID: 33972420 PMCID: PMC8157943 DOI: 10.1073/pnas.2015159118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Venom is a key adaptive innovation in snakes, and how nonvenom genes were co-opted to become part of the toxin arsenal is a significant evolutionary question. While this process has been investigated through the phylogenetic reconstruction of toxin sequences, evidence provided by the genomic context of toxin genes remains less explored. To investigate the process of toxin recruitment, we sequenced the genome of Bothrops jararaca, a clinically relevant pitviper. In addition to producing a road map with canonical structures of genes encoding 12 toxin families, we inferred most of the ancestral genes for their loci. We found evidence that 1) snake venom metalloproteinases (SVMPs) and phospholipases A2 (PLA2) have expanded in genomic proximity to their nonvenomous ancestors; 2) serine proteinases arose by co-opting a local gene that also gave rise to lizard gilatoxins and then expanded; 3) the bradykinin-potentiating peptides originated from a C-type natriuretic peptide gene backbone; and 4) VEGF-F was co-opted from a PGF-like gene and not from VEGF-A. We evaluated two scenarios for the original recruitment of nontoxin genes for snake venom: 1) in locus ancestral gene duplication and 2) in locus ancestral gene direct co-option. The first explains the origins of two important toxins (SVMP and PLA2), while the second explains the emergence of a greater number of venom components. Overall, our results support the idea of a locally assembled venom arsenal in which the most clinically relevant toxin families expanded through posterior gene duplications, regardless of whether they originated by duplication or gene co-option.
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Affiliation(s)
- Diego Dantas Almeida
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Vincent Louis Viala
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Pedro Gabriel Nachtigall
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Michael Broe
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210
| | - H Lisle Gibbs
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210
| | - Solange Maria de Toledo Serrano
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Ana Maria Moura-da-Silva
- Laboratório de Imunopatologia, Instituto Butantan, São Paulo 05503-900, Brazil
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas (UEA), Manaus 69040-000, Brazil
| | - Paulo Lee Ho
- Serviço de Bacteriologia, Divisão BioIndustrial, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Milton Yutaka Nishiyama-Jr
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Inácio L M Junqueira-de-Azevedo
- Laboratório de Toxinologia Aplicada, Center of Toxins, Immune-Response and Cell Signaling, Instituto Butantan, São Paulo 05503-900, Brazil;
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11
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Hofmann EP, Rautsaw RM, Mason AJ, Strickland JL, Parkinson CL. Duvernoy's Gland Transcriptomics of the Plains Black-Headed Snake, Tantilla nigriceps (Squamata, Colubridae): Unearthing the Venom of Small Rear-Fanged Snakes. Toxins (Basel) 2021; 13:336. [PMID: 34066626 PMCID: PMC8148590 DOI: 10.3390/toxins13050336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
The venoms of small rear-fanged snakes (RFS) remain largely unexplored, despite increased recognition of their importance in understanding venom evolution more broadly. Sequencing the transcriptome of venom-producing glands has greatly increased the ability of researchers to examine and characterize the toxin repertoire of small taxa with low venom yields. Here, we use RNA-seq to characterize the Duvernoy's gland transcriptome of the Plains Black-headed Snake, Tantilla nigriceps, a small, semi-fossorial colubrid that feeds on a variety of potentially dangerous arthropods including centipedes and spiders. We generated transcriptomes of six individuals from three localities in order to both characterize the toxin expression of this species for the first time, and to look for initial evidence of venom variation in the species. Three toxin families-three-finger neurotoxins (3FTxs), cysteine-rich secretory proteins (CRISPs), and snake venom metalloproteinases (SVMPIIIs)-dominated the transcriptome of T. nigriceps; 3FTx themselves were the dominant toxin family in most individuals, accounting for as much as 86.4% of an individual's toxin expression. Variation in toxin expression between individuals was also noted, with two specimens exhibiting higher relative expression of c-type lectins than any other sample (8.7-11.9% compared to <1%), and another expressed CRISPs higher than any other toxin. This study provides the first Duvernoy's gland transcriptomes of any species of Tantilla, and one of the few transcriptomic studies of RFS not predicated on a single individual. This initial characterization demonstrates the need for further study of toxin expression variation in this species, as well as the need for further exploration of small RFS venoms.
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Affiliation(s)
- Erich P. Hofmann
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA; (E.P.H.); (R.M.R.); (A.J.M.); (J.L.S.)
| | - Rhett M. Rautsaw
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA; (E.P.H.); (R.M.R.); (A.J.M.); (J.L.S.)
| | - Andrew J. Mason
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA; (E.P.H.); (R.M.R.); (A.J.M.); (J.L.S.)
| | - Jason L. Strickland
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA; (E.P.H.); (R.M.R.); (A.J.M.); (J.L.S.)
| | - Christopher L. Parkinson
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA; (E.P.H.); (R.M.R.); (A.J.M.); (J.L.S.)
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634, USA
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Nachtigall PG, Rautsaw RM, Ellsworth SA, Mason AJ, Rokyta DR, Parkinson CL, Junqueira-de-Azevedo ILM. ToxCodAn: a new toxin annotator and guide to venom gland transcriptomics. Brief Bioinform 2021; 22:6235957. [PMID: 33866357 DOI: 10.1093/bib/bbab095] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/15/2021] [Accepted: 03/03/2021] [Indexed: 01/23/2023] Open
Abstract
MOTIVATION Next-generation sequencing has become exceedingly common and has transformed our ability to explore nonmodel systems. In particular, transcriptomics has facilitated the study of venom and evolution of toxins in venomous lineages; however, many challenges remain. Primarily, annotation of toxins in the transcriptome is a laborious and time-consuming task. Current annotation software often fails to predict the correct coding sequence and overestimates the number of toxins present in the transcriptome. Here, we present ToxCodAn, a python script designed to perform precise annotation of snake venom gland transcriptomes. We test ToxCodAn with a set of previously curated transcriptomes and compare the results to other annotators. In addition, we provide a guide for venom gland transcriptomics to facilitate future research and use Bothrops alternatus as a case study for ToxCodAn and our guide. RESULTS Our analysis reveals that ToxCodAn provides precise annotation of toxins present in the transcriptome of venom glands of snakes. Comparison with other annotators demonstrates that ToxCodAn has better performance with regard to run time ($>20x$ faster), coding sequence prediction ($>3x$ more accurate) and the number of toxins predicted (generating $>4x$ less false positives). In this sense, ToxCodAn is a valuable resource for toxin annotation. The ToxCodAn framework can be expanded in the future to work with other venomous lineages and detect novel toxins.
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Affiliation(s)
- Pedro G Nachtigall
- Laboratório de Toxinologia Aplicada, CeTICS, Instituto Butantan, São Paulo, SP 05503-900, Brazil
| | - Rhett M Rautsaw
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Schyler A Ellsworth
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Andrew J Mason
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Darin R Rokyta
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Christopher L Parkinson
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, SC 29634, USA
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Heyborne WH, Mackessy SP. Venoms of New World Vinesnakes (Oxybelis aeneus and O. fulgidus). Toxicon 2020; 190:22-30. [PMID: 33307109 DOI: 10.1016/j.toxicon.2020.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/24/2020] [Accepted: 12/05/2020] [Indexed: 11/20/2022]
Abstract
Species of Oxybelis are extremely elongate arboreal snakes that are broadly distributed in the Americas, from extreme southeastern Arizona (USA) to central South America. Primarily feeding on lizards and birds, Oxybelis venoms are poorly known in general, but a prominent taxon-specific three-finger toxin (fulgimotoxin) was isolated from and is a prominent component of O. fulgidus venom; a homolog is also present in O. aeneus venom. As part of ongoing characterization of venoms from rear-fanged snakes, we describe here the composition of two broadly distributed species, O. aeneus and O. fulgidus. Venom proteomes were of very low complexity, and four protein families (LAAO, PIII SVMP, CRiSP and 3FTx) account for more than 90% of total protein composition. Venoms from both species are moderately toxic to mice and to Hemidactylus geckos, but they are nearly an order of magnitude more toxic to Anolis lizards (a native prey species). These results reflect a trend in colubrid venom composition that is becoming increasingly more common: the presence of taxon-specific toxins, specifically three-finger toxins, preferentially targeting lizards and/or birds.
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Affiliation(s)
- William H Heyborne
- School of Biological Sciences University of Northern Colorado, 501 20 th St., CB 92, Greeley, CO, 80639-0017, USA; Department of Biology Southern Utah University, 351 W University Blvd. Cedar City, UT, 84720, USA
| | - Stephen P Mackessy
- School of Biological Sciences University of Northern Colorado, 501 20 th St., CB 92, Greeley, CO, 80639-0017, USA.
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