The PIWI proteins SMEDWI-2 and SMEDWI-3 are required for stem cell function and piRNA expression in planarians
The PIWI proteins SMEDWI-2 and SMEDWI-3 are required for stem cell function and piRNA expression in planarians
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DOI：
10.1261/rna.1085008
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发表时间：
2008-06-01
期刊：
影响因子：
4.5
通讯作者：
Graveley, Brenton R.
中科院分区：
文献类型：
--
作者：
Palakodeti, Dasaradhi;Smielewska, Magda;Graveley, Brenton R.
PIWI蛋白在多种后生动物的生殖细胞中表达，在生殖细胞中它们参与一类称为PIWI相关RNA（piRNA）的新型小RNA的合成和功能。piRNA的一个功能是通过沉默转座子来保持种系基因组的完整性，尽管它们也参与表观遗传和转录后基因调控。在地中海涡虫中，PIWI蛋白SMEDWI-1和SMEDWI-2在新成细胞中表达，SMEDWI-2是再生和体内平衡所需的。在这里，我们确定了一个多样化的群体;类似于32个核苷酸的小RNA，非常类似于脊椎动物和昆虫的piRNA，并映射到S. mediterranea genome.这些RNA的表达主要发生在新母细胞中，并且不限于生殖系。SMEDWI-2或新鉴定的PIWI蛋白SMEDWI-3的RNAi敲低损害再生和稳态，并降低piRNA和新成细胞的水平。因此，SMEDWI-2和SMEDWI-3是S.地中海。
PIWI proteins are expressed in germ cells in a wide variety of metazoans, where they participate in the synthesis and function of a novel class of small RNAs called PIWI associated RNAs (piRNAs). One function of piRNAs is to preserve the integrity of the germline genome by silencing transposons, though they also participate in epigenetic and post-transcriptional gene regulation. In the planarian Schmidtea mediterranea, the PIWI proteins SMEDWI-1 and SMEDWI-2 are expressed in neoblasts and SMEDWI-2 is required for regeneration and homeostasis. Here, we identify a diverse population of; similar to 32-nucleotide small RNAs that strongly resemble vertebrate and insect piRNAs and map to hundreds of thousands of loci in the S. mediterranea genome. The expression of these RNAs occurs predominantly in neoblasts and is not restricted to the germline. RNAi knockdown of either SMEDWI-2 or a newly identified PIWI protein, SMEDWI-3, impairs regeneration and homeostasis and decreases the levels of both piRNAs and neoblasts. Therefore, SMEDWI-2 and SMEDWI-3 are required for piRNA expression, regeneration, and neoblast function in S. mediterranea.