title: Unraveling flp-11/flp-32 dichotomy in nematodes.
abstract: FMRFamide-like peptide (FLP) signalling systems are core to nematode neuromuscular function. Novel drug discovery efforts associated with nematode FLP/FLP receptor biology are advanced through the accumulation of basic biological data that can reveal subtle complexities within the neuropeptidergic system. This study reports the characterisation of FMRFamide-like peptide encoding gene-11 (flp-11) and FMRFamide-like peptide encoding gene-32 (flp-32), two distinct flp genes which encode the analogous peptide, AMRN(A/S)LVRFamide, in multiple nematode species - the only known example of this phenomenon within the FLPergic system of nematodes. Using bioinformatics, in situ hybridisation, immunocytochemistry and behavioural assays we show that: (i) flp-11 and -32 are distinct flp genes expressed individually or in tandem across multiple nematode species, where they encode a highly similar peptide; (ii) flp-11 does not appear to be the most widely expressed flp in Caenorhabditis elegans; (iii) in species expressing both flp-11 and flp-32, flp-11 displays a conserved, restricted expression pattern across nematode clades and lifestyles; (iv) in species expressing both flp-11 and flp-32, flp-32 expression is more widespread and less conserved than flp-11; (v) in species expressing only flp-11, the flp-11 expression profile is more similar to the flp-32 profile observed in species expressing both; and (vi) FLP-11 peptides inhibit motor function in multiple nematode species. The biological significance and evolutionary origin of flp-11 and -32 peptide duplication remains unclear despite attempts to identify a common ancestor; this may become clearer as the availability of genomic data improves. This work provides insight into the complexity of the neuropeptidergic system in nematodes, and begins to examine how nematodes may compensate for structural neuronal simplicity. From a parasite control standpoint, this work underscores the importance of basic biological data, and has wider implications for the utility of C. elegans as a model for parasite neurobiology.
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Louise E
authors.initials: LE
authors.lastname: Atkinson
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Iain R
authors.initials: IR
authors.lastname: Miskelly
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Christy L
authors.initials: CL
authors.lastname: Moffett
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Ciaran J
authors.initials: CJ
authors.lastname: McCoy
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Aaron G
authors.initials: AG
authors.lastname: Maule
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
authors.forename: Nikki J
authors.initials: NJ
authors.lastname: Marks
authors.affiliation: Microbes & Pathogen Biology, Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK. Electronic address: a.mousley@qub.ac.uk.
authors.forename: Angela
authors.initials: A
authors.lastname: Mousley
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000235:genetics; D019295:Computational Biology; D005786:Gene Expression Regulation; D006168:Guinea Pigs; D007106:Immune Sera / Q000276:immunology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008124:Locomotion; D018613:Microscopy, Confocal; D009348:Nematoda / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D009473:Neuronal Plasticity; D009479:Neuropeptides / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D017168:Rhabditida / Q000502:physiology; D016415:Sequence Alignment; D015398:Signal Transduction; D014251:Trichostrongyloidea / Q000502:physiology; D014431:Tylenchoidea / Q000502:physiology
chemical_list: D007106:Immune Sera; D009479:Neuropeptides; D018013:Receptors, Neuropeptide
keywords: FLP-11; FLP-32; FMRFamide-like peptide; Nematode; Neuropeptide; Neuropeptide signalling; flp-11; flp-32