The meiotic spindle and chromosomes in oocytes. Hiro Ohkura is Professor of Cell Biology at the University of Edinburgh. His group is studying the molecular regulation of the meiotic spindle and chromosomes in oocytes using Drosophila as a model system. Hiro did his PhD study on fission yeast mitosis in Prof Yanagida's lab in Kyoto University, Japan. He then worked as a postdoc in Prof Glover's lab in Dundee University, UK, studying Drosophila mitosis as well as fission yeast mitosis. He was awarded a Wellcome Senior Fellowship in 1997 and has established his lab in the University of Edinburgh, UK.He held a Wellcome Senior Research Fellowship for 20 years before becoming a Wellcome Investigator in 2018. Since 2024, he holds a Wellcome Discovery Award. Hiro Ohkura Ohkura Lab Website Lab members Igor Dasuzhau, Rayane Kaade, Ferdinand Meneau, Julia Niziol, Gera Pavlova, Emma Peat, Dan Tomlinson, Raluca Vintan, and Xiang Wang. Research Accurate segregation of chromosomal DNA is essential for life. An error in this process could result in cell death or aneuploidy. Furthermore, chromosome segregation in oocytes is error-prone in humans, and mis-segregation is a major cause of infertility, miscarriages and birth defects. Chromosome segregation in oocytes shares many similarities with those in somatic divisions, but also has notable differences. Distinct features of oocytes potentially hinder accurate chromosome segregation. They include (1) lack of centrosomes, the major microtubule nucleation centres in mitosis, (2) exceptionally large cell volume, and (3) cell cycle arrests at two stages. Oocytes are likely to have specific molecular mechanisms which mitigate negative impacts of these features, but little is known about how oocytes set up the chromosome segregation machinery. Defining the oocyte-specific mechanisms would be crucial to understand error-prone chromosome segregation in human oocytes. Furthermore, it may provide an insight into whether and how cancer cells might gain resistance to antimitotic drugs by activating these pathways.To understand the molecular pathways which set up the chromosome segregation machinery in oocytes, we take advantage of Drosophila oocytes as a "discovery platform" because of their similarity to mammalian oocytes and suitability for a approach combining Genetics, microscopy and biochemistry. In Drosophila oocytes, as in human oocytes, meiotic chromosomes form a compact cluster called the karyosome within the nucleus. Later, meiotic chromosomes assemble a bipolar spindle without centrosomes in the large volume of the cytoplasm, and establish bipolar attachment. We have identified genes/proteins and regulations specifically important for chromosome organisation and/or spindle formation in oocytes Image Selected publications Wan, X., Pavlova, G., Cullen, C. F., Dasuzhau, I., Ciszek, A., and Ohkura, H. (2025) Identification of locally activated spindle-associated proteins in oocytes uncovers a phosphatase-driven mechanism. J. Cell Sci. in press.Nieken, K. J., O'Brien, K., McDonnell, A., Zhaunova, L., and Ohkura, H. (2023) A large-scale RNAi screen reveals that mitochondrial function is important for meiotic chromosome organisation in oocytes. Chromosoma 132:1-18Repton, C., Cullen, C. F., Costa, M. F. A., Spanos, C., Rappsilber, J., and Ohkura, H. (2022) The phospho-docking protein 14-3-3 regulates microtubule-associated proteins in oocytes including the chromosomal passenger Borealin. PLoS Genetics 18:e1009995. Barbosa, P., Zhaunova, L., Debilio, S., Steccanella, V., Kelly, V., Ly, T., and Ohkura H. (2021) SCF-Fbxo42 promotes synaptonemal complex assembly by downregulating PP2A-B56. J. Cell Biol. 220, e202009167. This article was published on 2026-04-23
