Gurley Kyle A, Rink Jochen C, Sánchez Alvarado Alejandro
Department of Neurobiology and Anatomy, Howard Hughes Medical Institute, University of Utah School of Medicine, 401 MREB, 20N 1900E, Salt Lake City, UT 84132, USA.
Science. 2008 Jan 18;319(5861):323-7. doi: 10.1126/science.1150029. Epub 2007 Dec 6.
After amputation, freshwater planarians properly regenerate a head or tail from the resulting anterior or posterior wound. The mechanisms that differentiate anterior from posterior and direct the replacement of the appropriate missing body parts are unknown. We found that in the planarian Schmidtea mediterranea, RNA interference (RNAi) of beta-catenin or dishevelled causes the inappropriate regeneration of a head instead of a tail at posterior amputations. Conversely, RNAi of the beta-catenin antagonist adenomatous polyposis coli results in the regeneration of a tail at anterior wounds. In addition, the silencing of beta-catenin is sufficient to transform the tail of uncut adult animals into a head. We suggest that beta-catenin functions as a molecular switch to specify and maintain anteroposterior identity during regeneration and homeostasis in planarians.
截肢后，淡水涡虫能从产生的前端或后端伤口正确再生出头部或尾部。区分前后端并指导替换缺失的相应身体部位的机制尚不清楚。我们发现，在地中海真涡虫中，β-连环蛋白或蓬乱蛋白的RNA干扰（RNAi）会导致后端截肢时不恰当地再生出头部而非尾部。相反，β-连环蛋白拮抗剂腺瘤性息肉病蛋白的RNAi会导致前端伤口再生出尾部。此外，β-连环蛋白的沉默足以将未切割的成年动物的尾部转化为头部。我们认为，β-连环蛋白在涡虫的再生和体内平衡过程中作为一种分子开关，用于指定和维持前后身份。
