Structure of long telomeric RNA transcripts: the G-rich RNA forms a compact repeating structure containing G-quartets.

ABSTRACT: Recent studies have identified RNA transcripts arising from mammalian telomeres with the transcript of the C-rich strand (r(5'-UUAGGG-3')(n)) being much more abundant than transcripts of the G-rich strand. Here we used transmission electron microscopy, CD, and nuclease digestion to investigate the structure of approximately 640-nucleotide (nt) RNA transcripts of the C-rich and G-rich strands of mammalian telomeric DNA. The CD spectrum of the C-rich RNA in low salt (10 mm KCl) or high salt (100 mm KCl) was typical of mixed sequence RNA, whereas the CD spectrum for the G-rich RNA differed with changes characteristic of parallel G-quadruplexes at the higher salt concentration. Electron microscopy visualization of the C-rich RNA revealed relatively extended unstructured molecules 59.7 +/- 17.8

SUBMITTER: Randall A 

PROVIDER: S-EPMC2682846 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature