Identification and characterization of an oocyte factor required for sperm decondensation in pig

Abstract

Mammalian oocytes possess factors to support fertilization and embryonic development, but knowledge on these oocyte-specific factors is limited. In the current study, we demonstrated that porcine oocytes with the first polar body collected at 33 h of in vitro maturation sustain IVF with higher sperm decondensation and pronuclear formation rates and support in vitro development with higher cleavage and blastocyst rates, compared with those collected at 42 h (P!0.05). Proteomic analysis performed to clarify the mechanisms underlying the differences in developmental competence between oocytes collected at 33 and 42 h led to the identification of 18 differentially expressed proteins, among which protein disulfide isomerase associated 3 (PDIA3) was selected for further study. Inhibition of maternal PDIA3 via antibody injection disrupted sperm decondensation; conversely, overexpression of PDIA3 in oocytes improved sperm decondensation. In addition, sperm decondensation failure in PDIA3 antibody-injected oocytes was rescued by dithiothreitol, a commonly used disulfide bond reducer. Our results collectively report that maternal PDIA3 plays a crucial role in sperm decondensation by reducing protamine disulfide bonds in porcine oocytes, supporting its utility as a potential tool for oocyte selection in assisted reproduction techniques.

An integrated genome-wide multi-omics analysis of gene expression dynamics in the preimplantation mouse embryo

“…We selected three genes among those exhibiting strong negative correlations during preimplantation development and particularly from the 1- to the 4-cell stage: Pdia3, Top1, and DNAjb11. These genes are particularly appropriate in the context of our study, because mutations of Pdia3, Top1 and Dnajb11 interfere with development and prove lethal in homozygosis 46–49 . The results of the TaqMan assay for Pdia3, Top1 and Dnajb11 correlated positively with those of RNA-seq, as did the results of the immunofluorescence with those of LC-MS/MS (see Supplemental Fig.…”

Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila

“…Inhibition of glutathione synthesis by buthionine sulfoximine during oocyte maturation indeed efficiently blocks sperm nuclear decondensation and this effect can be reversed by DTT (refs 47, 48). Whether glutathione directly reduces SNBP disulfides in vivo or instead activates a dedicated disulfide reductase is still unresolved49. In most species, glutathione disulfide (GSSG) is reduced into glutathione (GSH) by the highly conserved glutathione reductase enzyme.…”

An integrated genome-wide multi-omics analysis of gene expression dynamics in the preimplantation mouse embryo

“…We selected three genes among those exhibiting strong negative correlations during preimplantation development and particularly from the 1-to the 4cell stage: Pdia3, Top1, and DNAjb11. These genes are particularly appropriate in the context of our study, because mutations of Pdia3, Top1 and Dnajb11 interfere with development and prove lethal in homozygosis(Morham et al 1996;Francisco et al 2010;Li et al 2014a;Wang et al 2014). The results of the TaqMan assay for Pdia3, Top1 and Dnajb11 correlated positively with those of RNA-seq, as did the results of the immunofluorescence with those of LC-MS/MS (see SupplementalFigure S19), confirming the existence of genes with strongly anticorrelated protein and transcript expression profiles.Finally, with the comfort of the validation data, we moved on to analyze the features of the genes at the extremes of the distribution of Spearman's rank correlation coefficients.…”