Ohtsuki's group

Our major research interest is to develop biomolecular technologies related to RNA and peptides/proteins that can assist biological studies and be used for biomedical applications.

  Intracellular delivery of RNAs and peptides

Methods enabling cellular uptake of RNAs and peptides have been widely utilized in various medical and biological studies. Our lab is investigating intracellular delivery of RNAs including short hairpin RNAs, microRNAs, and non-coding RNAs using cell-penetrating peptides (CPPs). We are also assessing efficient methods for CPP-mediated intracellular delivery of functional peptides/proteins including proapoptotic peptides. In addition, we are interested in developing photo- and ultrasound-dependent biomolecule delivery strategies.

  Photochemical internalization (PCI)

Endosomal entrapment is a major problem in intracellular macromolecule delivery based on the endocytic pathway. PCI uses light and photosensitizers, and is an efficient strategy for escaping endosomal entrapment of the delivered molecules. We are studying the molecular mechanisms of PCI and developing PCI-based delivery methods for macromolecules.

  Nanocomplexes for drug delivery

Another project in our laboratory is focused on the use of nanocomplexes for cancer therapy. We have constructed peptide/RNA nanoconjugates and polymeric nanomicelles for the delivery of therapeutic RNAs. Such nanoparticles tend to accumulate in tumors via the enhanced permeability and retention effect.

  Photo-regulation of translation and RNAi

Spatiotemporally photo-controlled translation is promising for investigating the biological roles of local translation in cells and tissues. We recently reported a method to photo-trigger protein synthesis using caged aminoacyl-tRNAs. We also devised a photoinduced RNAi strategy termed CLIP-RNAi (CPP-linked RBP-mediated RNA Internalization and Photoinduced RNAi), which enables spatiotemporal control of gene expression using visible and near-infrared light.

  Expansion of the protein biosynthesis system

Nonnatural amino acids can be incorporated into proteins by delivering an aminoacylated suppressor tRNA to a ribosome associated with mRNA containing an expanded codon/anticodon pair. This is a powerful tool for analyzing protein structure and function, and generating proteins with novel properties. We have devised artificial tRNAs and EF-Tu mutants for efficient incorporation of nonnatural amino acids and are pursuing applications of this expanded protein biosynthesis system.

  RNA detection and isolation

RNA detection methods are necessary to investigate biological roles of RNAs and are useful for clinical diagnostics. To address these goals, we are developing RNA detection methods. We have developed peptide nucleic acid (PNA)-based methods for RNA detection and RNA isolation. We have also devised a fluorescence lifetime probe to detect RNA degradation.

  CONTACT

Principal Investigator  Takashi Ohtsuki
Department of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
Email:  ohtsuk (at) okayama-u.ac.jp

  Takashi OHTSUKI, PhD, Professor

    Kazunori Watanabe, PhD, Assistant Professor

  ADMISSION

Application Guideline

If you are interested in joining our laboratory as a graduate student, please contact us via email to T. Ohtsuki.

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