title: A Polychaete's powerful punch: venom gland transcriptomics of Glycera reveals a complex cocktail of toxin homologs.
abstract: Glycerids are marine annelids commonly known as bloodworms. Bloodworms have an eversible proboscis adorned with jaws connected to venom glands. Bloodworms prey on invertebrates, and it is known that the venom glands produce compounds that can induce toxic effects in animals. Yet, none of these putative toxins has been characterized on a molecular basis. Here we present the transcriptomic profiles of the venom glands of three species of bloodworm, Glycera dibranchiata, Glycera fallax and Glycera tridactyla, as well as the body tissue of G. tridactyla. The venom glands express a complex mixture of transcripts coding for putative toxin precursors. These transcripts represent 20 known toxin classes that have been convergently recruited into animal venoms, as well as transcripts potentially coding for Glycera-specific toxins. The toxins represent five functional categories: Pore-forming and membrane-disrupting toxins, neurotoxins, protease inhibitors, other enzymes, and CAP domain toxins. Many of the transcripts coding for putative Glycera toxins belong to classes that have been widely recruited into venoms, but some are homologs of toxins previously only known from the venoms of scorpaeniform fish and monotremes (stonustoxin-like toxin), turrid gastropods (turripeptide-like peptides), and sea anemones (gigantoxin I-like neurotoxin). This complex mixture of toxin homologs suggests that bloodworms employ venom while predating on macroscopic prey, casting doubt on the previously widespread opinion that G. dibranchiata is a detritivore. Our results further show that researchers should be aware that different assembly methods, as well as different methods of homology prediction, can influence the transcriptomic profiling of venom glands.
authors.affiliation: Department of Life Sciences, The Natural History Museum, London, United Kingdom bmvr@arcor.de r.jenner@nhm.ac.uk bleidorn@uni-leipzig.de.
authors.forename: Björn M
authors.initials: BM
authors.lastname: von Reumont
authors.affiliation: Department of Life Sciences, The Natural History Museum, London, United Kingdom bmvr@arcor.de r.jenner@nhm.ac.uk bleidorn@uni-leipzig.de.
authors.forename: Lahcen I
authors.initials: LI
authors.lastname: Campbell
authors.affiliation: Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Germany.
authors.forename: Sandy
authors.initials: S
authors.lastname: Richter
authors.affiliation: Animal Evolution & Development, Institute of Biology, University of Leipzig, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Hering
authors.affiliation: Imaging and Analysis Centre, The Natural History Museum, London, United Kingdom.
authors.forename: Dan
authors.initials: D
authors.lastname: Sykes
authors.affiliation: Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Hetmank
authors.affiliation: Department of Life Sciences, The Natural History Museum, London, United Kingdom bmvr@arcor.de r.jenner@nhm.ac.uk bleidorn@uni-leipzig.de.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Jenner
authors.affiliation: Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Germany German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany bmvr@arcor.de r.jenner@nhm.ac.uk bleidorn@uni-leipzig.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bleidorn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005088:Exocrine Glands / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D011077:Polychaeta / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D014118:Toxins, Biological / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome; D014688:Venoms / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D014118:Toxins, Biological; D014688:Venoms
keywords: Annelida; Glycera; ShKT toxin; bloodworms; venom evolution; venomics