Woo Tai-Ting, Chao Ju-Lan, Yao Meng-Chao
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 11221, Taiwan Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
J Cell Sci. 2016 Mar 1;129(5):1046-58. doi: 10.1242/jcs.178236. Epub 2016 Jan 14.
Bi-directional non-coding transcripts and their ∼29-nt small RNA products are known to guide DNA deletion in Tetrahymena, leading to the removal of one-third of the genome from developing somatic nuclei. Using an antibody specific for long double-stranded RNAs (dsRNAs), we determined the dynamic subcellular distributions of these RNAs. Conjugation-specific dsRNAs were found and show sequential appearances in parental germline, parental somatic nuclei and finally in new somatic nuclei of progeny. The dsRNAs in germline nuclei and new somatic nuclei are likely transcribed from the sequences destined for deletion; however, the dsRNAs in parental somatic nuclei are unexpected, and PCR analyses suggested that they were transcribed in this nucleus. Deficiency in the RNA interference (RNAi) pathway led to abnormal aggregations of dsRNA in both the parental and new somatic nuclei, whereas accumulation of dsRNAs in the germline nuclei was only seen in the Dicer-like gene mutant. In addition, RNAi mutants displayed an early loss of dsRNAs from developing somatic nuclei. Thus, long dsRNAs are made in multiple nuclear compartments and some are linked to small RNA production whereas others might participate in their regulations.
已知双向非编码转录本及其约29个核苷酸的小RNA产物可引导四膜虫中的DNA缺失，从而导致发育中的体细胞核中三分之一的基因组被去除。我们使用一种对长双链RNA（dsRNA）具有特异性的抗体，确定了这些RNA在亚细胞水平的动态分布。我们发现了接合特异性dsRNA，并观察到它们在亲代生殖系、亲代体细胞核中依次出现，最终出现在子代的新体细胞核中。生殖系细胞核和新体细胞核中的dsRNA可能是从注定要被删除的序列转录而来；然而，亲代体细胞核中的dsRNA却出乎意料，PCR分析表明它们是在这个细胞核中转录的。RNA干扰（RNAi）途径的缺陷导致亲代和新体细胞核中dsRNA异常聚集，而生殖系细胞核中dsRNA的积累仅在类Dicer基因突变体中出现。此外，RNAi突变体显示发育中的体细胞核中dsRNA提前丢失。因此，长dsRNA在多个核区室中产生，一些与小RNA的产生有关，而另一些可能参与它们的调控。
