Tandem repeats of the 5' non-transcribed spacer of Tetrahymena rDNA function as high copy number autonomous replicons in the macronucleus but do not prevent rRNA gene dosage regulation
Language: 
English
Abstract: 

The rRNA genes in the somatic macronucleus of Tetrahymena thermophila are normally on 21 kb linear palindromic molecules (rDNA). We examined the effect on rRNA gene dosage of transforming T.thermophila macronuclei with plasmid constructs containing a pair of tandemly repeated rDNA replication origin regions unlinked to the rRNA gene. A significant proportion of the plasmid sequences were maintained as high copy circular molecules, eventually consisting solely of tandem arrays of origin regions. As reported previously for cells transformed by a construct in which the same tandem rDNA origins were linked to the rRNA gene [Yu, G.-L. and Blackburn, E. H. (1990) Mol. Cell. Biol., 10, 2070-2080], origin sequences recombined to form linear molecules bearing several tandem repeats of the origin region, as well as rRNA genes. The total number of rDNA origin sequences eventually exceeded rRNA gene copies by approximately 20- to 40-fold and the number of circular replicons carrying only rDNA origin sequences exceeded rRNA gene copies by 2- to 3-fold. However, the rRNA gene dosage was unchanged. Hence, simply monitoring the total number of rDNA origin regions is not sufficient to regulate rRNA gene copy number.

Author(s): 
Pan, W. J.
Blackburn, E. H.
Item Type: 
Journal Article
Publication Title: 
Nucleic Acids Research
Journal Abbreviation: 
Nucleic Acids Res.
Publication Date: 
5/11/1995
Publication Year: 
1995
Pages: 
1561-1569
Volume: 
23
Issue: 
9
ISSN: 
0305-1048
Library Catalog: 
NCBI Published Medical (?)
Extra: 
PMID: 7784211 PMCID: PMC306898

Turabian/Chicago Citation

W. J. Pan and E. H. Blackburn. 5/11/1995. "Tandem repeats of the 5' non-transcribed spacer of Tetrahymena rDNA function as high copy number autonomous replicons in the macronucleus but do not prevent rRNA gene dosage regulation." Nucleic Acids Research 23: 9: 1561-1569.

Wikipedia Citation

<ref> {{Cite journal | doi = | issn = 0305-1048 | volume = 23 | pages = 1561-1569 | last = Pan | first = W. J. | coauthors = Blackburn, E. H. | title = Tandem repeats of the 5' non-transcribed spacer of Tetrahymena rDNA function as high copy number autonomous replicons in the macronucleus but do not prevent rRNA gene dosage regulation | journal = Nucleic Acids Research | date = 5/11/1995 | pmid = | pmc = }} </ref>