Skip Navigation

This Article
Right arrow Print PDF (996K)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Challoner, P. U.
Right arrow Articles by Blackburn, E. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Challoner, P. U.
Right arrow Articles by Blackburn, E. H.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Nucleic Acids Research, 1985, Vol. 13, No. 7 2661-2680
© 1985

Articles

Conserved arrangements of repeated DNA sequences in nontranscribed spacers of ciliate ribosomal RNA genes: evidence for molecular coevolution

Peter U. Challoner1,*, Anthony A. Amin2, Ronald E. Pearlman2 and Elizabeth H. Blackburn2,+

1Department of Molecular Biology, University of California Berkeley, CA 94720, USA 2Department of Biology, York University 4700 Keele Street, Downsview, Ontario M3J 1P3, Canada

*To whom correspondence should be sent

Received September 19, 1984. Revised September 26, 1984. Accepted September 26, 1984.

We have analyzed the nucleotide sequences of the nontranscribed spacer (NTS) and transcription initiation and termination regions of the extrachromosomal rDNAs of the ciliated protozoans Tetrahymena thermophila and Glaucoma chattoni. The sequences surrounding The sites of transcription initiation and termination are highly conserved. The only extensive homologies of the NTS regions occur in five sets of dispersed repetitive sequences. Type I, II and III repeats in the 5' NTS are strongly conserved in sequence between Tetrahymena and Glaucoma in the case of the type I and III repeats, and in location relative to the transcription initiation site in the case of type I and II repeats. We Identify two new repeat types, designated IV and V, In the 3' NTS. The sequence of type IV repeats, and the location relative to the transcription termination site of type IV and V repeats, are conserved. All five types of repeats are interspersed with nonconserved DNA sequences. These results suggest that the five repeat types in the 5' and 3' NTSs are important in rRNA gene function; the sequence organization, and the differing rates of divergence between species of the repeat types, provide strong evidence for their functional selection through the process of molecular coevolution.

+ Present address: Fred Hutchinson Cancer Center, 1124 Columbia Street, Seattle, WA 98104, USA


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Nucleic Acids ResHome page
M. Mohammad, S. Saha, and G. M. Kapler
Three different proteins recognize a multifunctional determinant that controls replication initiation, fork arrest and transcription in Tetrahymena
Nucleic Acids Res., February 1, 2000; 28(3): 843 - 851.
[Abstract] [Full Text] [PDF]

Home page
 Mol. Cell. Biol.Home page
R. C. Gallagher and E. H. Blackburn
A Promoter Region Mutation Affecting Replication of the Tetrahymena Ribosomal DNA Minichromosome
Mol. Cell. Biol., May 1, 1998; 18(5): 3021 - 3033.
[Abstract] [Full Text]


Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.