SLERT Regulates DDX21 Rings Associated with Pol I Transcription

Publication date: 4 May 2017
Source:Cell, Volume 169, Issue 4
Author(s): Yu-Hang Xing, Run-Wen Yao, Yang Zhang, Chun-Jie Guo, Shan Jiang, Guang Xu, Rui Dong, Li Yang, Ling-Ling Chen
Dysregulated rRNA synthesis by RNA polymerase I (Pol I) is associated with uncontrolled cell proliferation. Here, we report a box H/ACA small nucleolar RNA (snoRNA)-ended long noncoding RNA (lncRNA) that enhances pre-rRNA transcription (SLERT). SLERT requires box H/ACA snoRNAs at both ends for its biogenesis and translocation to the nucleolus. Deletion of SLERT impairs pre-rRNA transcription and rRNA production, leading to decreased tumorigenesis. Mechanistically, SLERT interacts with DEAD-box RNA helicase DDX21 via a 143-nt non-snoRNA sequence. Super-resolution images reveal that DDX21 forms ring-shaped structures surrounding multiple Pol I complexes and suppresses pre-rRNA transcription. Binding by SLERT allosterically alters individual DDX21 molecules, loosens the DDX21 ring, and evicts DDX21 suppression on Pol I transcription. Together, our results reveal an important control of ribosome biogenesis by SLERT lncRNA and its regulatory role in DDX21 ring-shaped arrangements acting on Pol I complexes.

Graphical abstract

Teaser

A long non-coding RNA promotes pre-ribosomal RNA transcription by loosening the ring-shaped structure surrounding multiple RNA Pol I complexes formed by RNA helicase DDX21.


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