The small RNA repertoire of Dictyostelium discoideum and its regulation by components of the RNAi pathway
The small RNA repertoire of Dictyostelium discoideum and its regulation by components of the RNAi pathway
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DOI：
10.1093/nar/gkm707
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发表时间：
2007-11-01
影响因子：
14.9
通讯作者：
Soderbom, Fredrik
中科院分区：
文献类型：
--
作者：
Hinas, Andrea;Reimegard, Johan;Soderbom, Fredrik
小rna在许多真核生物的基因表达调控中起着至关重要的作用。在此，我们报道了社会性变形虫Dictyostelium disideum中1826 nt rna的克隆和特征。这项调查揭示了发育调节的microRNA候选物，其生物发生，至少在一种情况下，依赖于Dicer同源物DrnB。此外，我们鉴定了大量来自DIRS-1反转录转座子的21 nt rna，它们的簇被认为构成着丝粒。来自另一种反转录转座子Skipper的小RNA在第二种dicer样蛋白DrnA和假定的RNA依赖RNA聚合酶RrpC缺失的菌株中显著上调。相比之下，在分析的任何菌株中，DIRS-1小rna的表达没有改变。这表明盘状棘球蚴中存在多种RNAi途径。此外，我们还分离了几个与mrna具有反义互补的小rna。其中三种mrna受发育调控。有趣的是，所有三个对应的基因都表达较长的反义rna，而小rna可能来自这些反义rna。在至少一种情况下，较长的反义RNA与剪接的前mrna互补，而不是与未剪接的前mrna互补，表明是由RNA依赖的RNA聚合酶合成的。
Small RNAs play crucial roles in regulation of gene expression in many eukaryotes. Here, we report the cloning and characterization of 1826 nt RNAs in the social amoeba Dictyostelium discoideum. This survey uncovered developmentally regulated microRNA candidates whose biogenesis, at least in one case, is dependent on a Dicer homolog, DrnB. Furthermore, we identified a large number of 21 nt RNAs originating from the DIRS-1 retrotransposon, clusters of which have been suggested to constitute centromeres. Small RNAs from another retrotransposon, Skipper, were significantly up-regulated in strains depleted of the second Dicer-like protein, DrnA, and a putative RNA-dependent RNA polymerase, RrpC. In contrast, the expression of DIRS-1 small RNAs was not altered in any of the analyzed strains. This suggests the presence of multiple RNAi pathways in D. discoideum. In addition, we isolated several small RNAs with antisense complementarity to mRNAs. Three of these mRNAs are developmentally regulated. Interestingly, all three corresponding genes express longer antisense RNAs from which the small RNAs may originate. In at least one case, the longer antisense RNA is complementary to the spliced but not the unspliced pre-mRNA, indicating synthesis by an RNA-dependent RNA polymerase.