A Complex Set of Sex Pheromones Identified in the Cuttlefish Sepia officinalis

Abstract

BackgroundThe cephalopod mollusk Sepia officinalis can be considered as a relevant model for studying reproduction strategies associated to seasonal migrations. Using transcriptomic and peptidomic approaches, we aim to identify peptide sex pheromones that are thought to induce the aggregation of mature cuttlefish in their egg-laying areas.ResultsTo facilitate the identification of sex pheromones, 576 5′-expressed sequence tags (ESTs) were sequenced from a single cDNA library generated from accessory sex glands of female cuttlefish. Our analysis yielded 223 unique sequences composed of 186 singletons and 37 contigs. Three major redundant ESTs called SPα, SPα′ and SPβ were identified as good candidates for putative sex pheromone transcripts and are part of the 87 unique sequences classified as unknown. The alignment of translated SPα and SPα′ revealed a high level of conservation, with 98.4% identity. Translation led to a 248-amino acid precursor containing six peptides with multiple putative disulfide bonds. The alignment of SPα-α′ with SPβ revealed a partial structural conservation, with 37.3% identity. Translation of SPβ led to a 252-amino acid precursor containing five peptides. The occurrence of a signal peptide on SPα, SPα′ and SPβ showed that the peptides were secreted. RT-PCR and mass spectrometry analyses revealed a co-localization of transcripts and expression products in the oviduct gland. Preliminary in vitro experiments performed on gills and penises revealed target organs involved in mating and ventilation.ConclusionsThe analysis of the accessory sex gland transcriptome of Sepia officinalis led to the identification of peptidic sex pheromones. Although preliminary functional tests suggested the involvement of the α3 and β2 peptides in ventilation and mating stimulation, further functional investigations will make it possible to identify the complete set of biological activities expected from waterborne pheromones.

Crustacean cardioactive peptides: Expression, localization, structure, and a possible involvement in regulation of egg-laying in the cuttlefish Sepia officinalis

“…seaweeds, to form the egg mass. The successive ovulation, oocyte transport, encapsulation and fertilization steps are orchestrated by neuropeptides (Henry et al, 2013(Henry et al, , 1999(Henry et al, , 1997, ovarian regulatory peptides (Bernay et al, 2006, 2004, Zatylny et al, 2000a, 2000b, and sex pheromones (Enault et al, 2012). Although neuropeptides are not the only regulators involved in regulation of egg-laying mechanisms, they nevertheless play an important role in integrating environmental parameters such as the photoperiod, temperature, salinity or depth.…”

Neuropeptidome of the Cephalopod Sepia officinalis: Identification, Tissue Mapping, and Expression Pattern of Neuropeptides and Neurohormones during Egg Laying

“…Chemical communication probably plays an important role in these mechanisms. Boal and collaborators demonstrated that crude ovary and female accessory sex gland (ASG) extracts had an attracting power during behavioral tests, while Enault and collaborators recently characterized waterborne sex pheromones. In the squid Loligo pealeii , the occurrence of a β-microseminoprotein-like pheromone inducing extreme aggression in males was demonstrated in the egg mass .…”

Egg-Laying in the Cuttlefish Sepia officinalis

“…Using a transcriptomic approach, Enault and collaborators [9] discovered a third category of regulatory peptides, namely the sex pheromones expressed and released by the oviduct gland, and cleaved from three protein precursors into bioactive peptides ranging between 1.3 and 8 kDa.…”

“…In Sepia officinalis, Enault and collaborators [9] identified three major related transcripts encoding secreted peptides and expressed in the oviduct gland. RT-PCR and mass spectrometry analyses revealed that transcripts and expression products were co-localized in the oviduct gland.…”

“…Black box, signal peptide; vertical black line, potential dibasic residue cleavage site; asterisk, predicted N-linked glycosylation site; S, Cys residue [9].…”