With the help of a tiny flatworm best known for its extraordinary ability to regenerate lost tissue, researchers have identified a gene that controls the ability of stem cells to differentiate into specialized cells.借助一個小flatworm最出名的非凡再生能力失去了組織，研究人員已經確定了基因控制的能力，幹細胞分化成專門細胞。 The gene encodes a protein that is most similar to the protein PIWI which is an important regulator of stem cells in organisms ranging from plants to humans.該基因編碼一種蛋白質，這是最相似的蛋白質piwi這是一個重要調節幹細胞在生物體不等，從植物中給人類。 The significance of this study is enormous.的意義，這項研究是巨大的。 It sheds light on the most crucial aspect of stem cells - how they can transform into any cell of the body.它揭示了最關鍵的方面，幹細胞-他們如何能夠轉化為任何細胞的身體。

The research, performed at the University of Utah School of Medicine, was carried out by Helen Hay Whitney postdoctoral fellow Peter W. Reddien (Associate Member at the Whitehead Institute for Biomedical Research), and led by Howard Hughes Medical Institute investigator Alejandro Sánchez Alvarado.研究，表現在猶他州大學醫學院，進行了由海倫乾草惠特尼博士後研究員彼得瓦特reddien （準會員在白石研究所生物醫學研究） ，以及所領導的霍華德休斯醫學研究所調查亞歷杭桑切斯瓦拉多。

Freshwater flatworm planaria have amazing ability to regenerate.淡水flatworm planaria有驚人的再生能力。 Cut one of these animals in half, and a week later, two fully functional worms will have developed from the pieces.削減之一，這些動物的一半，一個星期後，兩個全功能的蠕蟲將發展從成碎片。 Cut a piece that is 1/279th the size of the animal, and it too will regrow into a complete worm.削減一塊是1/279th的大小動物，它也將再生一個完整的蠕蟲病毒。

Scientists got their first clues when they individually turned off 1,065 of the worm’s genes, and found 240 that were involved in some aspect of regeneration.科學家得到他們的第一線索，當他們單獨關閉， 1065年該蠕蟲的基因，並發現240個被涉及的在某些方面的再生能力。 Importantly, Sánchez Alvarado noted, 85 percent of these genes are found in the genomes of other organisms, including humans.重要的是，桑切斯瓦拉多指出， 85 ％的這些基因的發現，在基因組的其他生物，包括人類在內。 In the current study, the scientists zeroed in on one of these genes, called smedwi-2, that was active in dividing neoblasts.在目前的研究，科學家鎖定在一對這些基因的，所謂的smedwi - 2 ，這是活躍在劃分neoblasts 。

Smedwi-2 belongs to the Argonaute/PIWI protein family and is most similar to PIWI proteins found in fruit flies. smedwi - 2屬於向argonaute / piwi蛋白家族是最相似piwi蛋白質，發現在果蠅。 According to Sánchez Alvarado, PIWI proteins have been shown to play a role in regulating stem cells in plants and fruit flies, as well as humans.據桑切斯瓦拉多， piwi蛋白質已證明發揮作用，在調節幹細胞在植物和果蠅，以及人類。 “This encompasses millions of years of evolution,” he said. “這包含了數百萬年的演變， ”他說。 “Still, we don’t know exactly how this particular gene is doing its function in any of these organisms.” “我們仍然不知道究竟如何，這尤其是做基因及其功能，在任何這些有機體” 。

To find out, the scientists used RNA interference to specifically turn off the piwi gene in planaria.找出，科學家利用RNA干涉具體關閉piwi基因在planaria 。 When they did this, they found that worms had the same defects as those whose neoblasts have been destroyed by radiation — head regression, curling, and the inability to regenerate — suggesting that the gene was needed for normal neoblast function.當他們這樣做，他們發現蠕蟲病毒有相同的缺陷，作為那些neoblasts已被銷毀輻射-頭部回歸，冰壺，和無法再生-暗示該基因所需要的正常ne oblast功能。

The researchers examined piwi’s role more closely, and found that when they amputated part of a worm where the gene had been turned off, the stem cells were still able to detect the wound.研究人員piwi的角色更加緊密，並且發現，當他們被截肢的一個組成部分蠕蟲的地方基因已關閉，幹細胞仍然能夠偵測到傷口。 Amputation triggered the stem cells to divide, as in normal worms, and the daughter cells traveled proficiently to the part of the body where they were needed.截肢引發了幹細胞的分化，在正常的蠕蟲，和女兒走過的細胞熟練地向身體的一部分，他們需要。 However, once they arrived, they failed to replace the lost tissue.然而，一旦他們抵達，但並沒有以取代失去了組織。

When neoblasts divide, they produce at least two cell types – one copy of the original, and one cell that can develop into a specialized cell to replace a lost cell elsewhere in the body.當neoblasts鴻溝，他們所生產的至少有兩個類型的細胞-的一個副本原件和1細胞，可以發展成為一個專門的細胞，以取代失去了其他地方的細胞在人體內。 The researchers found that without piwi, the daughter cells from this division failed to differentiate into a specialized cell once they’d reached their destination.研究人員發現，沒有piwi ，女兒細胞從這個師未能分化成一個專門的細胞，一旦他們想要達到它們的目的地。 Based on their findings, Sánchez Alvarado said, “We think that piwi is actually involved in producing daughter cells that are competent to restore aged differentiated cells during homeostasis as well as missing tissues after amputation.根據他們的調查結果，桑切斯瓦拉多說， “我們認為， piwi ，其實是涉及在生產女兒的細胞，有能力恢復歲的分化細胞在穩態以及失踪組織後截肢。 Unlike what’s been thought about piwi for some time, which is that it was required to maintain the stem cell, we think that’s not happening here.不像什麼的一直思考piwi了一段時間，那就是它必須保持幹細胞，我們認為這不是發生在這裡。 The stem cells are being maintained by another mechanism, and it’s the division progeny, instead, that is being affected.”幹細胞正保持的另一種機制，這是該司的後代，相反，這是受到影響“ 。

There’s some evidence, Sánchez Alvarado said, that piwi plays a similar role in regulating the progeny of adult stem cells in humans.有一些證據顯示，桑切斯瓦拉多說， piwi扮演類似的角色，在規範的後代成人幹細胞在人體。 He cautioned that more work is needed to determine just how functionally similar the factors regulating stem cells in planaria are to those in higher organisms.他告誡說，需要做更多的工作，以確定如何在功能上類似的因素，調節幹細胞在planaria是那些在高等生物。 But so far there’s good evidence that many of the important genes are the same, he said.但到目前為止，有良好的證據表明，許多重要的基因是相同的，他說。

The current study begins the detailed analysis that will be needed to establish whether this humble worm can illuminate the mechanisms underlying the unique biology of stem cells.目前的研究開始詳細分析，認為將需要，以確定是否這個謙虛的蠕蟲病毒可以照亮機制獨特的生物學特性的幹細胞。

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