The neuropeptide complement of the marine annelid Platynereis dumerilii

Abstract

BackgroundThe marine annelid Platynereis dumerilii is emerging as a powerful lophotrochozoan experimental model for evolutionary developmental biology (evo-devo) and neurobiology. Recent studies revealed the presence of conserved neuropeptidergic signaling in Platynereis, including vasotocin/neurophysin, myoinhibitory peptide and opioid peptidergic systems. Despite these advances, comprehensive peptidome resources have yet to be reported.ResultsThe present work describes the neuropeptidome of Platynereis. We established a large transcriptome resource, consisting of stage-specific next-generation sequencing datasets and 77,419 expressed sequence tags. Using this information and a combination of bioinformatic searches and mass spectrometry analyses, we increased the known proneuropeptide (pNP) complement of Platynereis to 98. Based on sequence homology to metazoan pNPs, Platynereis pNPs were grouped into ancient eumetazoan, bilaterian, protostome, lophotrochozoan, and annelid families, and pNPs only found in Platynereis. Compared to the planarian Schmidtea mediterranea, the only other lophotrochozoan with a large-scale pNP resource, Platynereis has a remarkably full complement of conserved pNPs, with 53 pNPs belonging to ancient eumetazoan or bilaterian families. Our comprehensive search strategy, combined with analyses of sequence conservation, also allowed us to define several novel lophotrochozoan and annelid pNP families. The stage-specific transcriptome datasets also allowed us to map changes in pNP expression throughout the Platynereis life cycle.ConclusionThe large repertoire of conserved pNPs in Platynereis highlights the usefulness of annelids in comparative neuroendocrinology. This work establishes a reference dataset for comparative peptidomics in lophotrochozoans and provides the basis for future studies of Platynereis peptidergic signaling.

Large-Scale Combinatorial Deorphanization of Platynereis Neuropeptide GPCRs

“…Its larval stages represent accessible models for studying the role of neuropeptides in behavior, development, and physiology at the whole-organism level (Conzelmann et al, 2011(Conzelmann et al, , 2013bWilliams et al, 2015). Platynereis has an ancestral neuropeptide repertoire, including 30 ancestral bilaterian proneuropeptide families (Conzelmann et al, 2013a); however, only one neuropeptide receptor has been identified so far (Conzelmann et al, 2013b).…”

“…The majority of neuropeptides signal by G-protein-coupled receptors (GPCRs), with some exceptions (Chang et al, 2009;Leung et al, 1987;Lowe et al, 1989;Rechler and Nissley, 1985). While the neuropeptide repertoire of an animal can be determined using a combination of sequencing and mass-spectrometry approaches (Collins et al, 2010;Conzelmann et al, 2013a;Dircksen et al, 2011;Hauser et al, 2010;Li et al, 2008;Xie et al, 2010), the determination of neuropeptide receptors is more difficult and is usually carried out using in vitro experiments with individual peptide-receptor pairs. Several years of effort have led to the identification of 35 neuropeptide GPCRs in Drosophila melanogaster (Caers et al, 2012;Hewes and Taghert, 2001), 23 in Caenorhabditis elegans (Frooninckx et al, 2012), 50 in human and mouse, and only a few in non-model organisms (Bigot et al, 2014;Conzelmann et al, 2013b;Cox et al, 1997;Kim et al, 2010;Tensen et al, 1998aTensen et al, , 1998b.…”

“…Here, building on established transcriptomic and peptidomic resources (Conzelmann et al, 2013a), we present a large-scale deorphanization screen of Platynereis neuropeptide GPCRs. We identified the peptide ligand of 19 Platynereis receptors.…”

Myoinhibitory peptide regulates feeding in the marine annelidPlatynereis

“…We also looked at the change in expression of these digestive system marker genes and MIP across the Platynereis life cycle in stage-specific RNA-seq datasets [51].…”

“…DIG-labelled antisense RNA probes for the Platynereis MIP precursor (JX513877), MIP receptor (JX513876), alpha-amylase, subtilisin-1, subtilisin-2, legumain-protease precursor, and enteropeptidase were synthesized from purified PCR products of clones sourced from a Platynereis cDNA library [51]. RNA in situ hybridization using nitroblue tetrazolium (NBT)/5-bromo-4-chloro-3-indolyl phosphate (BCIP) staining combined with mouse antiacetylated-tubulin staining to highlight cilia and nervous system, followed by imaging with a Zeiss LSM 780 NLO confocal system and Zeiss ZEN2011 Grey software on an AxioObserver inverted microscope, was performed as previously described [50], with the following modification: fluorescence (instead of reflection) from the RNA in situ hybridization signal was detected using excitation at 633 nm in combination with a Long Pass 757 filter.…”