Nop9 is a PUF-like protein that prevents premature cleavage to correctly process pre-18S rRNA.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27725644.
- Also identified by DOI 10.1038/ncomms13085 and PMC identifier 5062617.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Numerous factors direct eukaryotic ribosome biogenesis, and defects in a single ribosome assembly factor may be lethal or produce tissue-specific human ribosomopathies. Pre-ribosomal RNAs (pre-rRNAs) must be processed stepwise and at the correct subcellular locations to produce the mature rRNAs. Nop9 is a conserved small ribosomal subunit biogenesis factor, essential in yeast. Here we report a 2.1-Å crystal structure of Nop9 and a small-angle X-ray-scattering model of a Nop9:RNA complex that reveals a 'C'-shaped fold formed from 11 Pumilio repeats. We show that Nop9 recognizes sequence and structural features of the 20S pre-rRNA near the cleavage site of the nuclease, Nob1. We further demonstrate that Nop9 inhibits Nob1 cleavage, the final processing step to produce mature small ribosomal subunit 18S rRNA. Together, our results suggest that Nop9 is critical for timely cleavage of the 20S pre-rRNA. Moreover, the Nop9 structure exemplifies a new class of Pumilio repeat proteins.
Medical subject headings
- RNA Processing, Post-Transcriptional
- RNA, Ribosomal, 18S
- RNA-Binding Proteins
- Saccharomyces cerevisiae
- Saccharomyces cerevisiae Proteins