一種名叫“渦蟲”的扁形蟲即使被切成百段,，一兩周后每段都會(huì)再生出完整的渦蟲。渦蟲這種超強(qiáng)再生能力一直是科學(xué)家感興趣的研究課題,。德國科學(xué)家最近發(fā)現(xiàn)了一種對(duì)渦蟲的再生能力有關(guān)鍵調(diào)節(jié)作用的蛋白質(zhì),。他們希望這一發(fā)現(xiàn)有助于人類干細(xì)胞研究。
近年來對(duì)渦蟲最感興趣的是從事干細(xì)胞研究的科學(xué)家,，因?yàn)檠芯堪l(fā)現(xiàn),，渦蟲再生的奧秘在于其體內(nèi)有一種散布全身的全能干細(xì)胞，其分化能力類似人類胚胎干細(xì)胞,。有所不同的是,，渦蟲這種干細(xì)胞能在任何時(shí)間分化成其他任何種類的細(xì)胞。渦蟲的身體被切斷后,，它體內(nèi)散布在各處的這些干細(xì)胞能轉(zhuǎn)變成神經(jīng),、肌肉、腸等各種組織細(xì)胞,，重新長出那些失去的部分,。
2010 干細(xì)胞技術(shù)與應(yīng)用講座 即將召開(4.15-16)
德國馬克斯·普朗克分子生物研究所31日宣布，該所科學(xué)家用核糖核酸（RNA）干擾抑制基因表達(dá)的方式抑制了渦蟲體內(nèi)蛋白質(zhì)“Smed－SmB”的合成，結(jié)果發(fā)現(xiàn)這導(dǎo)致渦蟲體內(nèi)的全能干細(xì)胞均不能分裂,，渦蟲因此失去了再生能力,。
參與研究的科學(xué)家說，這相當(dāng)于發(fā)現(xiàn)了影響渦蟲干細(xì)胞分裂的“總開關(guān)”,，這一發(fā)現(xiàn)可能有助于人們深入了解組織缺損修復(fù)的機(jī)理,。由于渦蟲細(xì)胞中四分之三的基因與人類基因相似，科學(xué)家還希望他們的研究成果有助于人類干細(xì)胞研究,。(生物谷Bioon.com)
Nature Medicine：多效生長因子可促進(jìn)造血干細(xì)胞再生
Nature Cell Biology：microRNA分子miR-151與肝癌轉(zhuǎn)移
生物谷-RNAi專題
生物谷推薦原文出處：
Development. doi: 10.1242/dev.042564
Smed-SmB, a member of the LSm protein superfamily, is essential for chromatoid body organization and planarian stem cell proliferation.
Fernandéz-Taboada E, Moritz S, Zeuschner D, Stehling M, Sch?ler HR, Saló E, Gentile L.
University of Barcelona, Department of Genetics, IBUB, Av. Diagonal 645, 08028, Barcelona, Spain.
Planarians are an ideal model system to study in vivo the dynamics of adult pluripotent stem cells. However, our knowledge of the factors necessary for regulating the 'stemness' of the neoblasts, the adult stem cells of planarians, is sparse. Here, we report on the characterization of the first planarian member of the LSm protein superfamily, Smed-SmB, which is expressed in stem cells and neurons in Schmidtea mediterranea. LSm proteins are highly conserved key players of the splicing machinery. Our study shows that Smed-SmB protein, which is localized in the nucleus and the chromatoid body of stem cells, is required to safeguard the proliferative ability of the neoblasts. The chromatoid body, a cytoplasmatic ribonucleoprotein complex, is an essential regulator of the RNA metabolism required for the maintenance of metazoan germ cells. However, planarian neoblasts and neurons also rely on its functions. Remarkably, Smed-SmB dsRNA-mediated knockdown results in a rapid loss of organization of the chromatoid body, an impairment of the ability to post-transcriptionally process the transcripts of Smed-CycB, and a severe proliferative failure of the neoblasts. This chain of events leads to a quick depletion of the neoblast pool, resulting in a lethal phenotype for both regenerating and intact animals. In summary, our results suggest that Smed-SmB is an essential component of the chromatoid body, crucial to ensure a proper RNA metabolism and essential for stem cell proliferation.
