During meiosis in the male of a cyprinodontid fish, Aphyosemion splendopleure, and during the organization of the spindle of division, the spindle is made of two types of tubules: microtubules (20-25 nm) and macrotubules (30-50 nm). The macrotubules are associated only with the polar region of the meiotic apparatus and are located outside the spindle of microtubules. At the end of meiosis, the spindle microtubules depolymerize whereas the macrotubules remain. One can find them throughout the entire process of spermiogenesis; later, they disappear only at the end of spermatid maturation. We have studied four populations from Cameroon, three of them with macrotubules.
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http://dx.doi.org/10.1016/0889-1605(85)90060-6 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Courant Institute for Mathematical Sciences and Department of Biology, New York University, New York, NY 10012.
Accurate chromosome segregation in mitosis depends on proper connections of sister chromatids, through microtubules, to the opposite poles of the early mitotic spindle. Transiently, many inaccurate connections are formed and rapidly corrected throughout the mitotic stages, but a small number of merotelic connections, in which a chromatid is connected to both spindle poles, remain lagging at the spindle's equator in anaphase. Most of the lagging chromatids are eventually moved to one or the other pole, likely by a combination of microtubules' turnover and the brute force of pulling by the microtubules' majority from the one pole against the microtubules' minority from the other pole.
View Article and Find Full Text PDFPLoS Genet
January 2025
Waksman Institute, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America.
Mitosis and meiosis have two mechanisms for regulating the accuracy of chromosome segregation: error correction and the spindle assembly checkpoint (SAC). We have investigated the function of several checkpoint proteins in meiosis I of Drosophila oocytes. Increased localization of several SAC proteins was found upon depolymerization of microtubules by colchicine.
View Article and Find Full Text PDFCytoplasmic dynein is an essential microtubule motor protein that powers organelle transport and mitotic spindle assembly. Its activity depends on dynein-dynactin-cargo adaptor complexes, such as dynein-dynactin-BicD2 (DDB), which typically function with two dynein motors. We show that mechanical tension recruits a third dynein motor via an auxiliary BicD adaptor binding the light intermediate chain of the third dynein, stabilizing multi-dynein assemblies and enhancing force generation.
View Article and Find Full Text PDFRedox Biol
January 2025
Department of Reproductive Medicine, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu, 210002, China; State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, 211166, China; Department of Reproductive Medicine, Affiliated Jinling Hospital, The First School of Clinical Medicine, Southern Medical University, Nanjing, 210002, China. Electronic address:
Oocyte aging is closely related to a decline in female fertility, accompanied by increased reactive oxygen species levels and changes in protein posttranslational modifications. However, the role of protein palmitoylation in oocyte aging has not been investigated. In the present study, a new association between redox and palmitoylation in aging oocytes was found.
View Article and Find Full Text PDFBMC Cancer
January 2025
Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, MP, India.
Epstein-Barr virus (EBV), an oncogenic gamma-herpesvirus, belongs to group 1 carcinogen and is implicated in various cancers, including gastric cancer. Aurora Kinase A is a major mitotic protein kinase that regulates mitotic progression; overexpression and hyperactivation of AURKA commonly promote genomic instability in many tumours. However, the relationship of functional residues of AURKA and EBV in gastric cancer progression remains unknown.
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