(c) flickr & DC Smith
生物の発生段階で，形成する臓器の種類や位置を決める際に生体内の電気信号がどう関与するか検討する実験が行われ，眼が背中や尾にあるカエルが作成された。この実験は，体のどのような構造も，それぞれ特定の膜電圧により形成が誘発されるとの仮説に基づいて行われた。カエルの胚の背中や尾にある細胞の電圧勾配を，正常な眼の細胞の電圧勾配と一致するよう遺伝子操作で変化させたところ，その場所に眼が形成された。この方法で他の臓器の形成も誘発できる可能性があり，将来，手足の形成，脳の修復など移植や再生医療に応用できると考えられる。（吉田素子）
Researchers Discover That Changes in Bioelectric Signals Trigger Formation of New Organs
Cause tadpoles to grow eyes in back, tail
For the first time, scientists have altered natural bioelectrical communication among cells to directly specify the type of new organ to be created at a particular location within a vertebrate organism. Using genetic manipulation of membrane voltage in Xenopus(frog)embryos, biologists at Tufts University's School of Arts and Sciences were able to cause tadpoles to grow eyes outside of the head area.
The researchers achieved most surprising results when they manipulated membrane voltage of cells in the tadpole's back and tail, well outside of where the eyes could normally form. "The hypothesis is that for every structure in the body there is a specific membrane voltage range that drives organogenesis," said Tufts post-doctoral fellow Vaibhav P. Pai Ph.D., first author of the paper, entitled "Transmembrane Voltage Potential Controls Embryonic Eye Patterning in Xenopus laevis." Pai noted, "These were cells in regions that were never thought to be able to form eyes. This suggests that cells from anywhere in the body can be driven to form an eye."
To do this, they changed the voltage gradient of cells in the tadpoles' back and tail to match that of normal eye cells. The eye-specific gradient drove the cells in the back and tail -- which would normally develop into other organs -- to develop into eyes.
These findings break new ground in the field of biomedicine because they identify an entirely new control mechanism that can be capitalized upon to induce the formation of complex organs for transplantation or regenerative medicine applications, according to Michael Levin, Ph.D., professor of biology and director of the Center for Regenerative and Developmental Biology at Tufts University's School of Arts and Sciences.
［単語和訳］
Researchers：研究者 Bioelectric Signals：生体電気信号 Trigger：～を引き起こす Organs：臓器 tadpoles：オタマジャクシ
cells：細胞 specify：～を特定する vertebrate organism：脊椎動物 genetic manipulation：遺伝子操作 membrane voltage：膜電圧 Xenopus：ツメガエル embryos：胚 biologists：生物学者
hypothesis：仮説 drives：推進する organogenesis：器官発生 post-doctoral fellow：博士研究員 Ph.D.：博士 first author：筆頭著者 entitled：～という題名の Transmembrane Voltage Potential：膜電位差 Embryonic：胚の Patterning：パターン形成 Xenopus laevis：アフリカツメガエル
voltage gradient：電圧勾配
break new ground：新しい境地を切り開く biomedicine：生物医学 can be capitalized upon：活用しうる induce：～を引き起こす transplantation：移植 regenerative medicine：再生医療 according to：～によると Developmental Biology：発生生物学
