Control mechanisms for the nuclear cycle-dependent processes in cortical division zone establishment

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06743
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44040:Morphology and anatomical structure-related
• Research Institution: University of Hyogo
• Principal Investigator: Mineyuki Yoshinobu 兵庫県立大学, 理学研究科, 客員研究員(研究員) (30219703)
• Co-Investigator(Kenkyū-buntansha): 玉置 大介 富山大学, 学術研究部理学系, 助教 (20793053) ; 中井 朋則 兵庫県立大学, 理学研究科, 助教 (60347531)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 分裂準備帯 / 微小管 / preprophase band / cdk / actin / 核・細胞質相互作用

Outline of Final Research Achievements

The preprophase band (PPB) is a cytokinetic apparatus that determines the division site in plant cells. It appears in G2 phase as a broad cortical microtubule band and narrows to define the cortical division zone where cell plate will attach at the end of cytokinesis. Although the microtubule band narrowing process is an important step in the division site determination, its molecular mechanism remains unclear. In the present study, we examined the role of two types of proteins, cyclin dependent kinases (CDKs) and actins, in the microtubule band narrowing process. RNA-seq analysis and immunofluorescent microscopy of onion root tips revealed that not only CDKA1;1 (cdc2) but also CDKB1;1 is involved in the development of PPB. By live cell imaging analysis of microtubules and actin filaments of tobacco BY-2 cells, we found the presence of actin filaments at the boundary of narrowing PPBs. This actin wall may be involved in preventing the dispersion of cortical microtubules.

Free Research Field

植物形態学

Academic Significance and Societal Importance of the Research Achievements

本研究で、PPBが狭くなる過程に新しいCDKの関与を示唆する事ができ、また、アクチンウォールが微小管帯の拡散を防ぐという新しい考えを示せた。植物の発生では、細胞分裂の際に新しい細胞分裂面がどこに挿入されたかで、娘細胞の将来の運命が左右される。幅の狭くなったPPBの領域が表層細胞分裂面挿入予定域（cortical division zone, CDZ）として細胞分裂の最後で細胞板の端が接続する場所になると考えられるため、PPBの幅が狭くなる過程の分子機構を明らかにすることは、植物の細胞レベルでの形態形成の最も重要な素過程の分子機構解明への新しい道を開くことにつながる。