실험실에서 광우병을 일으키는 변형 프리온 단백질을 만들어냈다는 1월 29일자 CBC 뉴스입니다.
미국과 중국의 과학자들이 생쥐 정상 프리온 단백질을 이용하여 세균의 세포에서 유전공학적 기법으로 실험적으로 변형 프리온 단백질을 인공적으로 만들어 냈다고 합니다.
연구진은 단백질이 세모막의 구성성분인 지방세포와 상호작용을 함으로써 변형이 되어 알파-나선 구조에서 베타-병풍 구조로 바뀐다는 사실을 밝혀냈다고 합니다.
이러한 연구결과를 [사이언스] 최신호에 기고한 공동연구자 오하이오주립대의 지얀 마(Jiyan Ma)는 이번 실험으로 광우병의 원인체가 알파-나선 구조에서 베타-병풍 구조로 잘못 겹치게 된 단백질(misfolded protein), 즉 변형 프리온 단백질이라는 사실을 규명했다고 밝혔습니다.
실험 쥐는 4개월 후 광우병 증상을 보였으나, 곧이어 사망했다고 합니다.
아직 사이언스에 발표한 논문 전문을 읽어보지는 못했구요… CBC 뉴스의 원문자료는 다음과 같습니다.
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Mad-cow proteins created in the lab
http://www.cbc.ca/technology/story/2010/01/29/tech-prion-disease.html?ref=rss
Prions are proteins that cause brain-wasting diseases such as Creutzfeld-Jakob Disease, also known as CJD, and mad cow disease, also known as bovine spongiform encephalopathy or BSE. (CBC)
Scientists have firmed up the evidence that misshapen protein are responsible for brain-wasting diseases by showing how these infectious prions are created.
Researchers from the United States and China have artificially created a disease-causing prion using proteins from mice.
Prions are proteins that occur naturally in the cells of mammals. Infectious prions are abnormal, misshapen versions of this protein that cause neurodegenerative diseases such as Creutzfeldt-Jakob disease and bovine spongiform encephalopathy, also known as mad cow disease.
The scientists used a mouse prion protein, called PrP, created through genetic engineering in bacterial cells in their experiments.
They found that the protein interacts with lipids, the fatty molecules in the structures of cell membranes, and becomes contorted and improperly folded, changing it into a disease-causing prion.
Jiyan Ma of Ohio State University said the experiment, published this week in Science, is the strongest evidence yet that prions are the cause of these brain-wasting diseases.
“The major thing we showed in this study is that the infectious agent in these diseases is truly a misfolded protein,” Ma said in a statement.
Ma and his colleagues at Ohio State and East China Normal University injected the artificially created prions into the brains of mice.
The mice started showing symptoms of brain-wasting disease about four months later. After the mice died, the researchers dissected their brains and found microscopic holes throughout, the classic sign of spongiform encephalopathy.
“We folded recombinant mouse prion protein into its normal shape, then converted it into a different conformation and showed that when it infected an animal, it caused full-blown prion disease, with all of the characteristics,” Ma said.
Ma said there is still much more research to be done on prions and brain-wasting disease.
“For example, we still don’t know what actually makes prions infectious or how their propagation causes damage in the brain,” he said.
