Small nucleolar RNA interference in Trypanosoma brucei: mechanism and utilization for elucidating the function of snoRNAs |
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| Authors: | Sachin Kumar Gupta Avraham Hury Yaara Ziporen Huafang Shi Elisabetta Ullu Shulamit Michaeli |
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| Institution: | 1The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900 Israel, 2Department of Internal Medicine and 3Department of Cell Biology, Yale University Medical School, New Haven, CT 06536-0812, USA |
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| Abstract: | Expression of dsRNA complementary to small nucleolar RNAs (snoRNAs) in Trypanosoma brucei results in snoRNA silencing, termed snoRNAi. Here, we demonstrate that snoRNAi requires the nuclear TbDCL2 protein, but not TbDCL1, which is involved in RNA interference (RNAi) in the cytoplasm. snoRNAi depends on Argonaute1 (Slicer), and on TbDCL2, suggesting that snoRNA dicing and slicing takes place in the nucleus, and further suggesting that AGO1 is active in nuclear silencing. snoRNAi was next utilized to elucidate the function of an abundant snoRNA, TB11Cs2C2 (92?nt), present in a cluster together with the spliced leader associated RNA (SLA1) and snR30, which are both H/ACA RNAs with special nuclear functions. Using AMT-UV cross-linking and RNaseH cleavage, we provide evidence for the interaction of TB11Cs2C2 with the small rRNAs, srRNA-2 and srRNA-6, which are part of the large subunit (LSU) rRNA. snoRNAi of TB11Cs2C2 resulted in defects in generating srRNA-2 and LSUβ rRNA. This is the first snoRNA described so far to engage in trypanosome-specific processing events. |
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