Establishing the bipolar spindle in mammalian oocytes after their prolonged arrest is crucial for meiotic fidelity and subsequent development. In contrast to somatic cells, the first meiotic spindle assembles in the absence of centriole-containing centrosomes. Ran-GTP can promote microtubule nucleation near chromatin, but additional unidentified factors are postulated for the activity of multiple acentriolar microtubule organizing centers in the oocyte. We now demonstrate that partially overlapping, nonredundant functions of Aurora A and Plk4 kinases contribute to initiate acentriolar meiosis I spindle formation. Loss of microtubule nucleation after simultaneous chemical inhibition of both kinases can be significantly rescued by drug-resistant Aurora A alone. Drug-resistant Plk4 can enhance Aurora A-mediated rescue, and, accordingly, Plk4 can phosphorylate and potentiate the activity of Aurora A in vitro Both kinases function distinctly from Ran, which amplifies microtubule growth. We conclude that Aurora A and Plk4 are rate-limiting factors contributing to microtubule growth as the acentriolar oocyte resumes meiosis.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5674873 | PMC |
http://dx.doi.org/10.1083/jcb.201606077 | DOI Listing |
BMC Mol Cell Biol
January 2025
Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK.
Background: During the latter stages of their development, mammalian oocytes under dramatic chromatin reconfiguration, transitioning from a non-surrounded nucleolus (NSN) to a surrounded nucleolus (SN) stage, and concomitant transcriptional silencing. Although the NSN-SN transition is known to be essential for developmental competence of the oocyte, less is known about the accompanying molecular changes. Here we examine the changes in the transcriptome and DNA methylation during the NSN to SN transition in mouse oocytes.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University of Texas Medical Branch, Galveston, TX, USA.
Background: Alzheimer's disease (AD) is a common form of dementia characterized by the accumulation of amyloid beta (Aβ) and phosphorylated tau proteins in the brain. While clinical observations are typically used for AD diagnosis, postmortem studies have revealed individuals without dementia symptoms but with high AD pathology, known as resilient individuals. Calcium permeable AMPA receptors (CP-AMPARs) have been implicated in the calcium dyshomeostasis of AD, but it is unclear whether they are found or behave differently at the electrophysiological level in resilient and control individuals compared to AD patients.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Indiana University, Bloomington, IN, USA.
Background: The roles of Aβ in the pathogenesis of Alzheimer 's disease (AD) include disruption of synaptic communication/function and synaptic plasticity mechanisms thought to underlie learning and memory. Exactly how these abnormal processes arise is incompletely understood, but evidence suggests that dysregulation of intracellular Ca levels is involved in alterations of neuronal excitability, synaptic remodeling, and neurodegeneration in AD. Our lab has focused on the potential involvement of voltage-gated potassium channels (VGKCs) in these processes, particularly Kv1.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
January 2025
Reproductive Medicine Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
Objective: To build a prediction nomogram for early prediction of live birth probabilities according to number of oocytes retrieved in women ≤ 35 years of age.
Methods: A prediction model was built including 9265 infertile women ≤ 35 years of age accepting their first ovum pick-up cycle from January 2018 to December 2022. Least absolute shrinkage and selection operator (LASSO) regression was performed to identify independent predictors and establish a nomogram to predict reproductive outcomes.
Andrology
January 2025
Institute for Advanced Biosciences, INSERM U 1209, CNRS UMR 5309, Université Grenoble Alpes, Team "Physiopathology and Pathophysiology of Sperm Cells", Grenoble, France.
Background: In mammals, sperm fertilization potential relies on efficient progression within the female genital tract to reach and fertilize the oocyte. This fundamental property is supported by the flagellum, an evolutionarily conserved organelle, which contains dynein motor proteins that provide the mechanical force for sperm propulsion and motility. Primary motility of the sperm cells is acquired during their transit through the epididymis and hyperactivated motility is acquired throughout the journey in the female genital tract by a process called capacitation.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!