Molecular analysis of radiation tolerance in extremotolerant tardigrades

2016 Fiscal Year Final Research Report

• Project/Area Number: 25281016
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: The University of Tokyo
• Principal Investigator: Kunieda Takekazu 東京大学, 理学(系)研究科(研究院), 助教 (10463879)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 放射線耐性 / クマムシ / 緩歩動物 / DNA損傷 / DNA保護 / Dsup

Outline of Final Research Achievements

Tardigrades, also known as water bears, are small aquatic animals living in various habitats. They enter an almost completely dehydrated state upon desiccation and exhibit exceptional tolerance against various physical extremes, including direct exposure to space. Here, we identified a novel tardigrade-unique protein named ‘Dsup’ (short for damage suppressor) from a chromatin fraction of a radiation-tolerant tardigrade, Ramazzottius varieornatus. Dsup protein forms a complex with DNA in vitro and is co-localized with nuclear DNA in cells. We engineered human cultured cells to stably express Dsup constitutively, and demonstrated that Dsup-expressing cells exhibited a substantially suppressed occurrence of DNA-breaks after X-ray irradiation and exposure to ROS. Furthermore, survival after X-ray irradiation was significantly improved in Dsup-expressing cells, some of which even retain proliferative ability, though untransfected cells completely cease proliferation.

Free Research Field

極限生物学