An egg must be fertilized by a single sperm only. To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules. These translocate from the oocyte's centre to the plasma membrane during meiosis. However, very little is known about the mechanism of cortical granule translocation. Here we investigate cortical granule transport and dynamics in live mammalian oocytes by using Rab27a as a marker. We show that two separate mechanisms drive their transport: myosin Va-dependent movement along actin filaments, and an unexpected vesicle hitchhiking mechanism by which cortical granules bind to Rab11a vesicles powered by myosin Vb. Inhibiting cortical granule translocation severely impaired the block to sperm entry, suggesting that translocation defects could contribute to miscarriages that are caused by polyspermy.
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http://dx.doi.org/10.1038/ncomms13726 | DOI Listing |
Front Biosci (Landmark Ed)
December 2024
Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA.
Background: Spatial-temporal control of mRNA translation in dendrites is important for synaptic plasticity. In response to pre-synaptic stimuli, local mRNA translation can be rapidly triggered near stimulated synapses to supply the necessary proteins for synapse maturation or elimination, and 3' untranslated regions (UTRs) are responsible for proper localization of mRNAs in dendrites. Although is a robust technique for analyzing RNA localization in fixed neurons, live-cell imaging of RNA dynamics remains challenging.
View Article and Find Full Text PDFAnn Med
December 2025
Department of Hebei Provincial Key Laboratory of Basic Medicine for Diabetes, The Shijiazhuang Second Hospital, Shijiazhuang, China.
Objectives: To explore the effect and the probable mechanisms of JLD in the treatment of type 2 diabetes mellitus (T2DM) - associated cognitive impairment (TDACI).
Methods: The effect of JLD in combating TDACI was assessed in T2DM model mice by conducting Morris water maze (MWM) behaviour testing. Active components and their putative targets, as well as TDACI-related targets, were collected from public databases.
Hippocampus
January 2025
Department of Child and Adolescent Psychology, Neuroscience & Physiology, and Psychiatry and the Neuroscience Institute, New York University Grossman School of Medicine, New York University Langone Health, New York, New York, USA.
For many years, the hilus of the dentate gyrus (DG) was a mystery because anatomical data suggested a bewildering array of cells without clear organization. Moreover, some of the anatomical information led to more questions than answers. For example, it had been identified that one of the major cell types in the hilus, the mossy cell, innervates granule cells (GCs).
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA.
Introduction: We investigated whether the cerebellum develops neuropathology that correlates with well-accepted Alzheimer's disease (AD) neuropathological markers and cognitive status.
Methods: We studied cerebellar cytoarchitecture in a cohort (N = 30) of brain donors. In a larger cohort (N = 605), we queried whether the weight of the contents of the posterior fossa (PF), which contains primarily cerebellum, correlated with dementia status.
J Reprod Dev
December 2024
Department of Integrated Applied Life Science, Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi, Yamanashi 400-0016, Japan.
Calcium release from the endoplasmic reticulum via sperm-derived phospholipase C zeta is crucial for oocyte activation during fertilization. Chloroquine (CQ) inhibits the increase in cytoplasmic calcium. This study investigated the effects of CQ on fertilization and oocyte activation.
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