Department of Genome Biology

Radiation Biology and Medical Genetics

Regulation of Genome Stability
  • Role of Trans-Lesion Synthesis DNA Polymerases on Mutagenesis
  • DNA Damage Response in Tissue Somatic Cell
  • Regulation of Mutagenesis in Tissue Stem Cell
  • Light and Life : DNA Repair and Circadian Rhythm
  • Trans-Generational Effect of Radioactive Materials
Professor Takeshi Todo
Radiation Biology and Medical Genetics
The Department of Radiation Biology and Medical Genetics was established in 1963. The first professor of the department was Dr. Sohei Kondo. Professor Taisei Nomura suceeded him in 1986. After the retirement of Professor Nomura, Todo became head in 2007.

Biological responses to environmental signals and stress including visible light, ultraviolet light and ionizing radiation.

"The maintenance of genome integrity is crucial for all organisms. However genome stability is continuously challenged by a diverse array of mutagenic forces. To maintain the genome integrity, several mechanisms have evolved. Multiple DNA repair pathways minimize the mutagenic consequences of DNA damage and erroneous DNA replication. Cell cycle checkpoint assures the efficient elimination of errors during DNA replication and chromosome segregation. Apoptosis is the most effective way to eliminate potentially deleterious cells carrying DNA damage. Each process has been well characterized at the molecular level. However, how each process contributes to the induction of genome instability is still unclear. Our aim is to clarify the role of each process on mutagenesis, especially the mutagenesis in tissue stem cells.

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Organisms utilize light energy in various ways. Within the visible spectrum, blue light is utilized by two related systems: 1) DNA photolyase, which repairs UV-induced DNA damage, and 2) cryptochrome, a photoreceptor in plants and insects and an essential component of circadian rhythms in vertebrates. We have found these two proteins are structurally related and constitute a large gene family. A basic common mechanism of these proteins underlying their distinct biological phenomena is the subject of our study. "

(Image 2)