5 research outputs found
Differential protein expression during sperm maturation and capacitation in an hermaphroditic bivalve,Pecten maximus(Linnaeus, 1758)
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-3-phosphate 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