Format

Send to

Choose Destination
J Mol Biol. 2019 May 3;431(10):1940-1955. doi: 10.1016/j.jmb.2019.03.010. Epub 2019 Mar 15.

G-Quadruplexes in Human Ribosomal RNA.

Author information

1
Center for the Origin of Life, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
2
Center for the Origin of Life, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
3
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
4
Center for the Origin of Life, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
5
Center for the Origin of Life, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA. Electronic address: loren.williams@chemistry.gatech.edu.

Abstract

rRNA is the single most abundant polymer in most cells. Mammalian rRNAs are nearly twice as large as those of prokaryotes. Differences in rRNA size are due to expansion segments, which contain extended tentacles in metazoans. Here we show that the terminus of an rRNA tentacle of Homo sapiens contains 10 tandem G-tracts that form highly stable G-quadruplexes in vitro. We characterized rRNA of the H. sapiens large ribosomal subunit by computation, circular dichroism, UV melting, fluorescent probes, nuclease accessibility, electrophoretic mobility shifts, and blotting. We investigated Expansion Segment 7 (ES7), oligomers derived from ES7, intact 28S rRNA, 80S ribosomes, and polysomes. We used mass spectrometry to identify proteins that bind to rRNA G-quadruplexes in cell lysates. These proteins include helicases (DDX3, CNBP, DDX21, DDX17) and heterogeneous nuclear ribonucleoproteins. Finally, by multiple sequence alignments, we observe that G-quadruplex-forming sequences are a general feature of LSU rRNA of Chordata but not, as far as we can tell, of other species. Chordata ribosomes present polymorphic tentacles with the potential to switch between inter- and intramolecular G-quadruplexes. To our knowledge, G-quadruplexes have not been reported previously in ribosomes.

KEYWORDS:

Chordates; expansion segments; helicases; polysomes; rRNA

PMID:
30885721
DOI:
10.1016/j.jmb.2019.03.010

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center