Artificial models for gravity-sensitive cytoplasm – Publicly Invited Research 2018－2019

  1. A01 Ogura
  2. A01 H. Takahashi
  3. A01 S. Takahashi
  4. A01 Michiue
  5. A01 Hinoi
  6. A01 Tsumoto
  7. A01 Nikawa
  8. A01 Chatani
  9. A01 Kawakami
  10. A01 Akiyama
  11. A01 Tomita
  1. A02 Shinohara
  2. A02 Mieda
  3. A02 Maekawa
  4. A02 Abe
  5. A02 Ohgami
  6. A02 Kawano
  7. A02 Takano
  1. A03 Suzuki
  2. A03 Nakamura
  3. A03 Harada
  4. A03 Kobayashi
  5. A03 Miyamoto
  6. A03 Funayama
  7. A03 Kakinuma
  1. B01 Lazarus
  2. B01 Kato
  3. B01 Kunieda
  4. B01 Kitaya
  5. B01 Sawano
Research Subject Artificial models for gravity-sensitive cytoplasm
Research Group Leader
name
Research Collaborator(s)
  • Katsuzumi Okumura
    Professor, Graduate School of Bioresources, Mie University
  • Kingo Takiguchi
    Associate Professor/Lecturer, Graduate School of Science, Nagoya University
  • Kenichi Yoshikawa, Takahiro Kenmotsu
    Professors, Faculty of Biological and Medical Sciences, Doshisha University

Microdroplets with submicron (sizes of biomacromolecules) – micron diameters (cell-size) are spontaneously generated through liquid-liquid phase separation (LLPS) in aqueous solutions of mutually immiscible hydrophilic polymers. We intend to entrap fundamental biochemical processes/reactions like DNA replication, transcription/translation and actin polymerization inside such aqueous microdroplets. Microcompartmentalization based on this micro-segregation by LLPS provides slightly different densities to the interior and exterior of the microdroplets.

Usually, on Earth (1 G environment), fusion (coalescence) among the microdroplets may be promoted by the gravity along with colloidal attractions. In this project, we try to investigate how the entrapped biochemical processes affect dynamic behavior of the micro-segregated states, which we would associate with inhomogeneous intracellular structures.

Since intracellular environments contain abundant biomacromolecules, such as nucleic acids, proteins, polysaccharides and lipids, with crowded states, it seems possible that macro-segregated phases could be developed even under 1 G; thus, in actual cells, micro phases might apparently be sustained by some biochemical/biophysical mechanisms.

We here adopt an aqueous two phase system (ATPS) composed of polyethylene glycol (PEG) and dextran (DEX) to simply prepare aqueous/aqueous microdroplet: The ATPS technique is well known as a classic and established moderate method for biomolecular separation. We will first try to find conditions that make the droplets relatively stable for long duration at around 1 G, and evaluate effects of entrapped biomolecules and reactions on dynamics of the micro-segregation phases.