ジャーナル: PLoS One / 年: 2022 タイトル: Cryo-ET detects bundled triple helices but not ladders in meiotic budding yeast. 著者: Olivia X Ma / Wen Guan Chong / Joy K E Lee / Shujun Cai / C Alistair Siebert / Andrew Howe / Peijun Zhang / Jian Shi / Uttam Surana / Lu Gan / 要旨: In meiosis, cells undergo two sequential rounds of cell division, termed meiosis I and meiosis II. Textbook models of the meiosis I substage called pachytene show that nuclei have conspicuous 100-nm- ...In meiosis, cells undergo two sequential rounds of cell division, termed meiosis I and meiosis II. Textbook models of the meiosis I substage called pachytene show that nuclei have conspicuous 100-nm-wide, ladder-like synaptonemal complexes and ordered chromatin loops. It remains unknown if these cells have any other large, meiosis-related intranuclear structures. Here we present cryo-ET analysis of frozen-hydrated budding yeast cells before, during, and after pachytene. We found no cryo-ET densities that resemble dense ladder-like structures or ordered chromatin loops. Instead, we found large numbers of 12-nm-wide triple-helices that pack into ordered bundles. These structures, herein called meiotic triple helices (MTHs), are present in meiotic cells, but not in interphase cells. MTHs are enriched in the nucleus but not enriched in the cytoplasm. Bundles of MTHs form at the same timeframe as synaptonemal complexes (SCs) in wild-type cells and in mutant cells that are unable to form SCs. These results suggest that in yeast, SCs coexist with previously unreported large, ordered assemblies.
凍結剤: NITROGEN / 装置: FEI VITROBOT MARK IV 詳細: The Vitrobot's cup was used to condense the ethane cryogen. Crimped copper tubes containing cell paste were held ~ 3 cm above the surface of the liquid ethane, then dropped..