Gametogenesis in animal oocytes reduces the diploid genome content of germline precursors to a haploid state in gametes by discarding ¾ of the duplicated chromosomes through a sequence of two meiotic cell divisions called meiosis I and II. The assembly of the microtubule-based spindle structure that mediates this reduction in genome content remains poorly understood compared to our knowledge of mitotic spindle assembly and function. In this review, we consider the diversity of oocyte meiotic spindle assembly and structure across animal phylogeny, review recent advances in our understanding of how animal oocytes assemble spindles in the absence of the centriole-based microtubule-organizing centers that dominate mitotic spindle assembly, and discuss different models for how chromosomes are captured and moved to achieve chromosome segregation during oocyte meiotic cell division.
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http://dx.doi.org/10.1016/bs.ctdb.2015.11.031 | DOI Listing |
Cytoskeleton (Hoboken)
January 2025
Department of Life Sciences, University of Siena, Siena, Italy.
We analysed here the dynamic of the kinesin-like Pavarotti (Pav) during male gametogenesis of wild-type and Sas4 mutant flies. Pav localizes to the equatorial region and the inner central spindle of late anaphase wild-type spermatogonia and displays a strong concentration at the midbody during late telophase. At metaphase of the first meiotic division, Pav shows widespread localization on the equatorial region of the spermatocytes.
View Article and Find Full Text PDFCell Commun Signal
January 2025
Laboratory of Theriogenology, College of Veterinary Medicine, Chungnam National University, Daejeon, 34134, Republic of Korea.
Background: Although the Notch signaling pathway is known to play an important role in ovarian follicle development in mammals, whether it is involved in oocyte maturation remains unclear. Therefore, this study was performed to elucidate the existence and role of the Notch signaling pathway during oocyte maturation in a porcine model.
Methods: Reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemical assays were used to determine the existence of Notch signaling pathway-related transcripts and proteins in porcine cumulus-oocyte complexes (COCs).
Aging Cell
January 2025
State Key Laboratory of Animal Biotech Breeding, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China.
With advancing age, significant changes occur in the female reproductive system, the most notable of which is the decline in oocyte quality, a key factor affecting female fertility. However, the mechanisms underlying oocyte aging remain poorly understood. In this study, we obtained oocytes from aged and young female mice and performed single-cell transcriptome sequencing, comparing our findings with existing proteomic analyses.
View Article and Find Full Text PDFAndrology
December 2024
Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, China.
Background: The establishment of kinetochore-microtubule attachment is essential for error-free chromosome alignment and segregation during cell division. Defects in chromosome alignment result in chromosome instability, birth defects, and infertility. Kinesin-7 CENP-E mediates kinetochore-microtubule capture, chromosome alignment, and spindle assembly checkpoint in somatic cells, however, mechanisms of CENP-E in germ cells remain poorly understood.
View Article and Find Full Text PDFDev Cell
December 2024
Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; Cell Biology and Biophysics Unit, EMBL, 69117 Heidelberg, Germany. Electronic address:
Centrosomes organize microtubules that are essential for mitotic divisions in animal cells. They consist of centrioles surrounded by pericentriolar material (PCM). Questions related to mechanisms of centriole assembly, PCM organization, and spindle microtubule formation remain unanswered, partly due to limited availability of molecular-resolution structural data inside cells.
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