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Van Bocxlaer I, Maex M, Treer D, Janssenswillen S, Janssens R, Vandebergh W, Proost P, Bossuyt F. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae). Sci Rep 2016; 6:21880. [PMID: 26935790 PMCID: PMC4776240 DOI: 10.1038/srep21880] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/18/2016] [Indexed: 11/09/2022] Open
Abstract
Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF’s were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide.
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Affiliation(s)
- Ines Van Bocxlaer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Dag Treer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Sunita Janssenswillen
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Rik Janssens
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Wim Vandebergh
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, KU Leuven - University of Leuven, Minderbroedersstraat 10 - box 1030, B-3000 Leuven, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
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Van Bocxlaer I, Treer D, Maex M, Vandebergh W, Janssenswillen S, Stegen G, Kok P, Willaert B, Matthijs S, Martens E, Mortier A, de Greve H, Proost P, Bossuyt F. Side-by-side secretion of Late Palaeozoic diverged courtship pheromones in an aquatic salamander. Proc Biol Sci 2015; 282:20142960. [PMID: 25694622 PMCID: PMC4345460 DOI: 10.1098/rspb.2014.2960] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Males of the advanced salamanders (Salamandroidea) attain internal fertilization without a copulatory organ by depositing a spermatophore on the substrate in the environment, which females subsequently take up with their cloaca. The aquatically reproducing modern Eurasian newts (Salamandridae) have taken this to extremes, because most species do not display close physical contact during courtship, but instead largely rely on females following the male track at spermatophore deposition. Although pheromones have been widely assumed to represent an important aspect of male courtship, molecules able to induce the female following behaviour that is the prelude for successful insemination have not yet been identified. Here, we show that uncleaved sodefrin precursor-like factor (SPF) protein pheromones are sufficient to elicit such behaviour in female palmate newts (Lissotriton helveticus). Combined transcriptomic and proteomic evidence shows that males simultaneously tail-fan multiple ca 20 kDa glycosylated SPF proteins during courtship. Notably, molecular dating estimates show that the diversification of these proteins already started in the late Palaeozoic, about 300 million years ago. Our study thus not only extends the use of uncleaved SPF proteins outside terrestrially reproducing plethodontid salamanders, but also reveals one of the oldest vertebrate pheromone systems.
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Affiliation(s)
- Ines Van Bocxlaer
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Dag Treer
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Wim Vandebergh
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Sunita Janssenswillen
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Gwij Stegen
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Philippe Kok
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Bert Willaert
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Severine Matthijs
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Erik Martens
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium
| | - Anneleen Mortier
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium
| | - Henri de Greve
- Structural and Molecular Microbiology, Structural Biology Research Centre, VIB, Pleinlaan 2, 1050 Brussels, Belgium Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
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Janssenswillen S, Willaert B, Treer D, Vandebergh W, Bossuyt F, Van Bocxlaer I. High pheromone diversity in the male cheek gland of the red-spotted newt Notophthalmus viridescens (Salamandridae). BMC Evol Biol 2015; 15:54. [PMID: 25888438 PMCID: PMC4379952 DOI: 10.1186/s12862-015-0333-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/09/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Male salamanders (Urodela) often make use of pheromones that are produced in sexually dimorphic glands to persuade the female into courtship and mating. The mental gland of lungless salamanders (Plethodontidae) and dorsal cloacal glands (or abdominal glands) of newts (Salamandridae) have been particularly well studied in that respect. In both families, sodefrin precursor-like factor (SPF) proteins have been identified as major components of the courtship pheromone system. However, similar to plethodontids, some newts also make use of subtle head glands during courtship, but few pheromones have been characterized from such structures. Males of red-spotted newts (Notophthalmus viridescens, Salamandridae) have both cloacal and cheek (genial) glands, and are known to apply secretions to the female's nose by both tail-fanning and cheek-rubbing. Here we combined transcriptomic and phylogenetic analyses to investigate the presence, diversity and evolution of SPF proteins in the cloacal and cheek glands of this species. RESULTS Our analyses indicate that the cheek glands of male N. viridescens produce a similar amount and diversity of SPF isoforms as the cloacal glands in this species. Expression in other tissues was much lower, suggesting that both male-specific courtship glands secrete SPF pheromones during courtship. Our phylogenetic analyses show that N. viridescens expresses a combination of isoforms that stem from four highly diverged evolutionary lineages of SPF variants, that together form a basis for the broad diversity of SPF precursors in the breeding glands. CONCLUSIONS The similar SPF expression of cheek and cloacal glands suggests that this protein family is used for pheromone signalling through cheek rubbing in the red-spotted newt. Since several male salamandrids in other genera have comparable head glands, SPF application via other glands than the cloacal glands may be more widespread than currently appreciated in salamandrids.
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Affiliation(s)
- Sunita Janssenswillen
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Bert Willaert
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Dag Treer
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Wim Vandebergh
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Franky Bossuyt
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
| | - Ines Van Bocxlaer
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050, Brussels, Belgium.
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Janssenswillen S, Vandebergh W, Treer D, Willaert B, Maex M, Van Bocxlaer I, Bossuyt F. Origin and diversification of a salamander sex pheromone system. Mol Biol Evol 2014; 32:472-80. [PMID: 25415963 DOI: 10.1093/molbev/msu316] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Sex pheromones form an important facet of reproductive strategies in many organisms throughout the Animal Kingdom. One of the oldest known sex pheromones in vertebrates are proteins of the Sodefrin Precursor-like Factor (SPF) system, which already had a courtship function in early salamanders. The subsequent evolution of salamanders is characterized by a diversification in courtship and reproduction, but little is known on how the SPF pheromone system diversified in relation to changing courtship strategies. Here, we combined transcriptomic, genomic, and phylogenetic analyses to investigate the evolution of the SPF pheromone system in nine salamandrid species with distinct courtship displays. First, we show that SPF originated from vertebrate three-finger proteins and diversified through multiple gene duplications in salamanders, while remaining a single copy in frogs. Next, we demonstrate that tail-fanning newts have retained a high phylogenetic diversity of SPFs, whereas loss of tail-fanning has been associated with a reduced importance or loss of SPF expression in the cloacal region. Finally, we show that the attractant decapeptide sodefrin is cleaved from larger SPF precursors that originated by a 62 bp insertion and consequent frameshift in an ancestral Cynops lineage. This led to the birth of a new decapeptide that rapidly evolved a pheromone function independently from uncleaved proteins.
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Affiliation(s)
- Sunita Janssenswillen
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Wim Vandebergh
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Dag Treer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Bert Willaert
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Margo Maex
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Ines Van Bocxlaer
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Franky Bossuyt
- Amphibian Evolution Lab, Biology Department, Vrije Universiteit Brussel (VUB), Brussels, Belgium
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Willaert B, Bossuyt F, Janssenswillen S, Adriaens D, Baggerman G, Matthijs S, Pauwels E, Proost P, Raepsaet A, Schoofs L, Stegen G, Treer D, Van Hoorebeke L, Vandebergh W, Van Bocxlaer I. Frog nuptial pads secrete mating season-specific proteins related to salamander pheromones. ACTA ACUST UNITED AC 2013; 216:4139-43. [PMID: 23948475 DOI: 10.1242/jeb.086363] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Males of many frog species develop spiny nuptial pads with underlying glands on their thumbs during the mating period. We used 3D visualization on the European common frog Rana temporaria to show that the morphology of these glands allows the channelling of secreted molecules to the pad's surface during amplexus. Combined transcriptome and proteome analyses show that proteins of the Ly-6/uPAR family, here termed amplexins, are highly expressed in the nuptial glands during the mating season, but are totally absent outside that period. The function of amplexins remains unknown, but it is interesting to note that they share structural similarities with plethodontid modulating factors, proteins that influence courtship duration in salamanders.
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Affiliation(s)
- Bert Willaert
- Vrije Universiteit Brussel, Biology Department, Amphibian Evolution Lab, Pleinlaan 2, B-1050 Brussels, Belgium
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Vandebergh W, Maex M, Bossuyt F, Van Bocxlaer I. Recurrent functional divergence of early tetrapod keratins in amphibian toe pads and mammalian hair. Biol Lett 2013; 9:20130051. [PMID: 23485876 DOI: 10.1098/rsbl.2013.0051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Amphibians have invaded arboreal habitats multiple times independently during their evolution. Adaptation to these habitats was nearly always accompanied by the presence or appearance of toe pads, flattened enlargements on tips of fingers and toes that provide adhesive power in these environments. The strength and elasticity of the toe pad relies on polygonal arrayed cells ending in nanoscale projections, which are densely packed with cytoskeletal proteins. Here, we characterized and determined the evolutionary origin of these proteins in the toe pad of the tree frog Hyla cinerea. We created a subtracted cDNA library enriching genes that are expressed in the toe pad, but nowhere else in the toe. Our analyses revealed five alpha keratins as main structural proteins of the amphibian toe pad. Phylogenetic analyses show that these proteins belong to different keratin lineages that originated in an early tetrapod ancestor and in mammals evolved to become the major keratin types of hair. The ancestral keratins were probably already expressed in areas that required skin reinforcement in early tetrapods, and subsequently diverged to support fundamentally different adaptive structures in amphibians and mammals.
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Affiliation(s)
- Wim Vandebergh
- Biology Department, Amphibian Evolution Lab, Vrije Universiteit Brussel, , Pleinlaan 2, Brussels 1050, Belgium.
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Vandebergh W, Bossuyt F. Radiation and Functional Diversification of Alpha Keratins during Early Vertebrate Evolution. Mol Biol Evol 2011; 29:995-1004. [DOI: 10.1093/molbev/msr269] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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