In mammals, sperm-egg interaction is based on molecular events either unique to gametes or also present in somatic cells. In gamete fusion, it is unknown which features are gamete specific and which are shared with other systems. Conformational changes mediated by thiol-disulfide exchange are involved in the activation of some virus membrane fusion proteins. Here we asked whether that mechanism is also operative in sperm-egg fusion. Different inhibitors of protein disulfide isomerase (PDI) activity were able to inhibit sperm-egg fusion in vitro. While pretreatment of oocytes had no effect, pretreatment of sperm reduced their fusion ability. Some members of the PDI family were detected on the sperm head, and use of specific antibodies and substrates suggested that the oxidoreductase ERp57 has a role in gamete fusion. The results support the idea that thiol-disulfide exchange is a mechanism that may act in gamete fusion to produce conformational changes in fusion-active proteins.
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http://dx.doi.org/10.1016/j.devcel.2006.03.011 | DOI Listing |
Development
January 2025
Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
Upon fertilization, male and female nuclei fuse to form the zygotic nucleus in angiosperms. Karyogamy is considered to be essential for proper embryogenesis; however, the transcriptional dynamics during karyogamy in plant zygotes remain unclear. In this study, we performed a single-cell transcriptome analysis of rice zygotes at six early developmental stages (15 min, 30 min, 1 h, 2 h, 4 h, and 6 h after gamete fusion) to reveal gene expression profiles during karyogamy in plant zygotes.
View Article and Find Full Text PDFBiomedicines
December 2024
Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (MNGHA), Riyadh 11426, Saudi Arabia.
Mammalian fertilization is a complex and highly regulated process that has garnered significant attention, particularly with advancements in assisted reproductive technologies such as in vitro fertilization (IVF). The fusion of egg and sperm involves a sequence of molecular and cellular events, including capacitation, the acrosome reaction, adhesion, and membrane fusion. Critical genetic factors, such as IZUMO1, JUNO (also known as FOLR4), CD9, and several others, have been identified as essential mediators in sperm-egg recognition and membrane fusion.
View Article and Find Full Text PDFBMC Plant Biol
December 2024
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
Background: Transgenic plants expressing proteins that target the eggs of the ubiquitous plant pest Bemisia tabaci (whitefly) could be an effective insecticide strategy. Two approaches for protein delivery are assessed using the mCherry reporter gene in transgenic tomato plants, while accommodating autofluorescence in both the plant, phloem-feeding whitefly and pedicle-attached eggs.
Results: Both transgenic strategies were segregated to homozygous genotype using digital PCR.
J Transl Med
December 2024
Department of Biological Science, University of Tulsa, Tulsa, Oklahoma, USA.
Background: The mechanisms enabling sperm to locate unfertilized eggs within the fallopian tubes remain a subject of debate in reproductive biology. Previous studies using polytocous mammals observed a 1:1 sperm-egg ratio within the ampulla at the time of fertilization. From these observations, it is hypothesized that this mechanism could be linked to sperm-egg fusion, such that unfertilized eggs may attract sperm until fusion occurs, whereupon the attraction ceases.
View Article and Find Full Text PDFPLoS Biol
December 2024
Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
Starvation, which is associated with inactivation of the growth-promoting TOR complex 1 (TORC1), is a strong environmental signal for cell differentiation. In the fission yeast Schizosaccharomyces pombe, nitrogen starvation has distinct physiological consequences depending on the presence of mating partners. In their absence, cells enter quiescence, and TORC1 inactivation prolongs their life.
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