Diversity of nuclear pore structure in the binucleate ciliate Tetrahymena

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06632
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44010:Cell biology-related
• Research Institution: Nihon University
• Principal Investigator: IWAMOTO Masaaki 日本大学, 文理学部, 教授 (80450683)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 核膜孔複合体 / ヌクレオポリン / 免疫電子顕微鏡法 / 核分化 / テトラヒメナ / 繊毛虫

Outline of Final Research Achievements

The ciliate Tetrahymena is a binucleate organism that has two types of nuclei with different functions, the macronucleus (MAC) and the micronucleus (MIC), within the same cell. It was known that the nuclear pore complexes (NPCs) of the MAC and MIC are composed of partly different but mostly common nuclear pore proteins. However, it was unclear whether the core scaffolds of the NPCs formed by these common components were the same shape or different between MAC and MIC. In this study, the arrangement of the common nuclear pore proteins within the NPC was examined by immunoelectron microscopy. It was found that the same set of nuclear pore proteins form core scaffolds with largely different shapes in the NPCs of MAC and MIC.

Free Research Field

細胞生物学、分子生物学、原生生物学

Academic Significance and Societal Importance of the Research Achievements

核膜孔複合体に関するこれまでの研究の多くは、オピストコンタに属する出芽酵母や哺乳類細胞を用いて行われてきたことから、核膜孔複合体の構造と機能は単細胞生物から高等動物まで広く保存されたものと認識されている。しかしながら、アルベオラータに属するテトラヒメナの大核の核膜孔複合体は、まったく新奇の構造を呈するものだった。この知見は、核膜孔複合体は考えられていた以上にバリエーションに富んだ構造体であることを示唆しており、テトラヒメナの核膜孔複合体の多様な構造と、大核および小核に特有の核機能との関連性を調べることによって、今後、核膜孔複合体の未知の機能が明らかになっていくものと期待される。