Allele-specific, selective amplification of a ribosomal RNA gene in Tetrahymena thermophila
Language: 
English
Abstract: 

The amplification of ribosomal DNA during development of the somatic macronucleus in Tetrahymena thermophila was analyzed by genetic and molecular biological techniques. We have identified an alternate form of the rDNA, structurally distinguishable from the wild-type by an extra cutting site for Bam HI in its nontranscribed spacer. The altered rDNA was inherited in crosses in a simple Mendelian fashion, consistent with the presence of only one rRNA gene copy per haploid genome in the micronucleus. We therefore define a locus for the rRNA structural gene, the rdnA locus, with the allele determining the alternate form designated rdnA1. In over 95% of T. thermophila clones heterozygous for the rdnA locus in the micronucleus (rdnA1/rdn+), the macronucleus, which develops from a division product of this micronucleus, contained almost exclusively rdnA1-type amplified palindromic rDNA molecules. The rdnA1 allele is thus almost always dominant over the rdn+ allele with respect to amplification. This genetic variant of the rdnA locus was used to show that the single, free, nonpalindromic rRNA genes, which are synthesized during rDNA amplification, are derived from micronuclear gene copies from both chromosomal homologs. We therefore conclude that in these heterozygotes, selective amplification of the rdnA1 allele is not caused by the production of only one type of free, single rRNA gene during amplification.

Author(s): 
Pan, W. C.
Orias, E.
Flacks, M.
Blackburn, E. H.
Item Type: 
Journal Article
Publication Title: 
Cell
Journal Abbreviation: 
Cell
Publication Date: 
1982-03
Publication Year: 
1982
Pages: 
595-604
Volume: 
28
Issue: 
3
ISSN: 
0092-8674
Library Catalog: 
NCBI Published Medical (?)
Extra: 
PMID: 6280878

Turabian/Chicago Citation

W. C. Pan, E. Orias, M. Flacks and E. H. Blackburn. 1982-03. "Allele-specific, selective amplification of a ribosomal RNA gene in Tetrahymena thermophila." Cell 28: 3: 595-604.

Wikipedia Citation

<ref> {{Cite journal | doi = | issn = 0092-8674 | volume = 28 | pages = 595-604 | last = Pan | first = W. C. | coauthors = Orias, E., Flacks, M., Blackburn, E. H. | title = Allele-specific, selective amplification of a ribosomal RNA gene in Tetrahymena thermophila | journal = Cell | date = 1982-03 | pmid = | pmc = }} </ref>