一种名叫“涡虫”的扁形虫即使被切成百段，一两周后每段都会再生出完整的涡虫。涡虫这种超强再生能力一直是科学家感兴趣的研究课题。德国科学家最近发现了一种对涡虫的再生能力有关键调节作用的蛋白质。他们希望这一发现有助于人类干细胞研究。
近年来对涡虫最感兴趣的是从事干细胞研究的科学家，因为研究发现，涡虫再生的奥秘在于其体内有一种散布全身的全能干细胞，其分化能力类似人类胚胎干细胞。有所不同的是，涡虫这种干细胞能在任何时间分化成其他任何种类的细胞。涡虫的身体被切断后，它体内散布在各处的这些干细胞能转变成神经、肌肉、肠等各种组织细胞，重新长出那些失去的部分。
2010 干细胞技术与应用讲座 即将召开(4.15-16)
德国马克斯·普朗克分子生物研究所31日宣布，该所科学家用核糖核酸（RNA）干扰抑制基因表达的方式抑制了涡虫体内蛋白质“Smed－SmB”的合成，结果发现这导致涡虫体内的全能干细胞均不能分裂，涡虫因此失去了再生能力。
参与研究的科学家说，这相当于发现了影响涡虫干细胞分裂的“总开关”，这一发现可能有助于人们深入了解组织缺损修复的机理。由于涡虫细胞中四分之三的基因与人类基因相似，科学家还希望他们的研究成果有助于人类干细胞研究。(生物谷Bioon.com)
Nature Medicine：多效生长因子可促进造血干细胞再生
Nature Cell Biology：microRNA分子miR-151与肝癌转移
生物谷-RNAi专题
生物谷推荐原文出处：
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.
