The olfactory secretome varies according to season in female sheep and goat

Abstract

BackgroundSmall ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulatory cycle of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored at the peripheral level of odours reception. As it was shown in pig that the olfactory secretome (proteins secreted in the nasal mucus) could be modified under hormonal control, we monitored its composition in females of both species through several reproductive seasons, thanks to a non-invasive sampling of olfactory mucus. For this purpose, two-dimensional gel electrophoresis (2D-E), western-blot with specific antibodies, MALDI-TOF and high-resolution (nano-LC-MS/MS) mass spectrometry, RACE-PCR and molecular modelling were used.ResultsIn both species the olfactory secretome is composed of isoforms of OBP-like proteins, generated by post-translational modifications, as phosphorylation, N-glycosylation and O-GlcNAcylation. Important changes were observed in the olfactory secretome between the sexual rest and the sexual activity periods, characterised in ewe by the specific expression of SAL-like proteins and the emergence of OBPs O-GlcNAcylation. In goat, the differences between SA and SR did not come from new proteins expression, but from different post-translational modifications, the main difference between the SA and SR secretome being the number of isoforms of each protein. Proteomics data are available via ProteomeXchange with identifier PXD014833.ConclusionDespite common behaviour, seasonal breeding, and genetic resources, the two species seem to adapt their olfactory equipment in SA by different modalities: the variation of olfactory secretome in ewe could correspond to a specialization to detect male odours only in SA, whereas in goat the stability of the olfactory secretome could indicate a constant capacity of odours detection suggesting that the hallmark of SA in goat might be the emission of specific odours by the sexually active male. In both species, the olfactory secretome is a phenotype reflecting the physiological status of females, and could be used by breeders to monitor their receptivity to the male effect.

Identification of potential chemosignals in the European water vole Arvicola terrestris

“…Phosphorylated peptides from rat urinary proteins have been identified at a consensus site for FAM20C 28 , an enzyme that phosphorylates numerous secreted proteins 31 . There is no such site in arvicolin, no more than in porcine OBP sequence where phosphorylation sites were unambiguously localised however 30 , nor in ovine and caprine OBPs 32 , nor in Giant Panda OBP4 33 , also phosphorylated. Thus, if the report of phosphorylation of OBP and related proteins is increasing 27,28,30,32,33 , the molecular pathway and enzymes involved are far from to be understood.…”

“…There is no such site in arvicolin, no more than in porcine OBP sequence where phosphorylation sites were unambiguously localised however 30 , nor in ovine and caprine OBPs 32 , nor in Giant Panda OBP4 33 , also phosphorylated. Thus, if the report of phosphorylation of OBP and related proteins is increasing 27,28,30,32,33 , the molecular pathway and enzymes involved are far from to be understood. Conversely, the O -GlcNAcylation of OBPs is less reported, although very interesting as a regulating key of OBP binding specificity to VOCs or pheromone components 30,32 .…”

“…Thus, if the report of phosphorylation of OBP and related proteins is increasing 27,28,30,32,33 , the molecular pathway and enzymes involved are far from to be understood. Conversely, the O -GlcNAcylation of OBPs is less reported, although very interesting as a regulating key of OBP binding specificity to VOCs or pheromone components 30,32 . The presence of O -GlcNAc on arvicolin is ascertained by (1) the high specificity of CTD110.6 antibodies and (2) the fact that arvicolin is the only protein localised in the labelled band in males.…”

“…The presence of O -GlcNAc on arvicolin is ascertained by (1) the high specificity of CTD110.6 antibodies and (2) the fact that arvicolin is the only protein localised in the labelled band in males. The sex-difference in phosphorylation and O -GlcNAcylation has been proposed to be governed by hormones 27,30,32 .

Figure 7Immunodetection of post translational modifications. ( a ) Western-blot with Q7 antibodies for detection of phospho-threonine-modified proteins, ( b ) Western-blot with CTD110.6 antibody for O -GlcNAcylated proteins detection, C+: BSA- O -GlcNAc (5 ng).

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Odorant-binding proteins in canine anal sac glands indicate an evolutionarily conserved role in mammalian chemical communication

“…In vaginal secretions, saliva, tears and urine of rodents, they are an essential part of signalling complexes that are exchanged during sexual and other social interactions [ 32 , 35 , 59 , 69 , 85 – 89 ]. In nasal mucosa of elephants, rodents, and some ungulates (pig, cow, goat, sheep), OBP proteins assist with the perception of molecules inhaled from the environment [ 77 , 78 , 90 – 94 ]. The function of OBP in other mammals and the role of anal sac glands in carnivore scent signalling together provide a compelling indication that canine OBP proteins contribute to conspecific chemical communication.…”