Differential protein expression during sperm maturation and capacitation in an hermaphroditic bivalve,Pecten maximus(Linnaeus, 1758)

Abstract

In order to investigate the mechanisms of final maturation and capacitation of spermatozoa in Pecten maximus, we used a 2D proteomic approach coupled with MALDI-TOF/TOF mass spectrometry (MS) and bioinformatics search against the Pecten database, to set up a reference map of the proteome of spawned spermatozoa, and identified 133 proteins on the basis of the EST database. These proteins are mainly involved in energy production, ion and electron transport (44%), cell movement (22%) and developmental processes (10%). Comparison between proteomes of spermatozoa collected before and after transit through the genital ducts of P. maximus led to the identification of differentially expressed proteins. Most of them are associated with energy metabolism (aconitate hydratase, malate dehydrogenase, glyceraldehyde-3phosphate dehydrogenase), indicating important modifications of energy production during transit in gonoducts, potentially linked with acquisition of sperm motility. Three proteins involved in cell movement (Tektin-2, tubulin and microtubule-associated protein RP/EB family member 3) were down-regulated in spermatozoa stripped from the gonad. 40S ribosomal protein SA, involved in maturation of 40S ribosomal subunits, was also found to be down-regulated in spermatozoa obtained by induced spawning, suggesting reduction of the efficiency of RNA translation, a characteristic of late spermatozoon differentiation. These results confirm that maturation processes of P. maximus spermatozoa during transit through the gonoduct involve RNA translation, energy metabolism and structural proteins implicated in cell movement. Spermatozoa maturation processes clearly differ between P. maximus and gonochoric or alternately hermaphroditic bivalves, potentially in relation to reproductive strategies: the final maturation of the spermatozoon along the genital tract probably contributes to reduction of autofertilization in this simultaneously hermaphroditic species.

Transcriptomic analysis of female and male gonads in juvenile snakeskin gourami (Trichopodus pectoralis)

“…Although information regarding the function of the F-box only protein 36 (fbxo36) relating to the reproductive system is limited, a high level of fbxo36 transcripts was observed in our study. Similarly, by means of proteomic analysis, upregulation of the FBXO36 protein was detectable during sperm maturation and capacitation in the bivalve Pecten maximus 47 . Myb-related protein B (mybl2) was reported to activate the transcription of mitotic genes 48 .…”

Differential DNA methylation in Pacific oyster reproductive tissue in response to ocean acidification

“…Serine/threonine-protein kinase genes were also differentially methylated in C. virginica gonad [12]. As a catalyst of the TCA cycle, cytoplasmic aconitate hydratase is upregulated during spermatogenesis in C. gigas and downregulated during spermatogenesis in P. maximus, with differing consequences for energy metabolism [43,44]. Early examination of C. virginia found cytoplasmic aconitate hydratase localized to eggs, with enzyme activity increasing during embryogenesis [45].…”

RNA-seq coupled to proteomic analysis reveals high sperm proteome variation between two closely related marine mussel species

“…So far only a few proteomics studies have focussed on sperm cells, mostly in widely studied model organisms (see [4,14]). The ascidian Ciona intestinales [15], the red abalone Haliotis rufescens [16], the Pacific oyster Crassostrea gigas [17], the king scallop Pecten maximus [18] and the marine mussels Mytilus edulis [19][20] and M. galloprovincialis [21], are the only marine organisms, all of them external fertilisers, currently in the sperm cell proteomic literature. Furthermore to the best of our knowledge, there are no comparative quantitative proteomic studies of sperm of closely related species, with the exception of an analysis of different ungulate and rodent species [14,22].…”