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Tetrahymena telomerase is active as a monomer
Tetrahymena telomerase is active as a monomer.
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Telomerase is an enzyme that utilizes an internal RNA molecule as a template for the extension of chromosomal DNA ends. The catalytic core of telomerase consists of the RNA subunit and a protein reverse transcriptase subunit, known as telomerase reverse transcriptase (TERT). It has previously been shown that both yeast and human telomerase can form dimers or multimers in which one RNA in the complex can influence the activity of another. To test the proposal that dimerization might be essential for telomerase activity, we sought to determine whether Tetrahymena thermophila telomerase is active as a dimer or a monomer. Recombinant Tetrahymena telomerase eluted from a gel filtration column at the size of a monomeric complex (one RNA plus one TERT), and those fractions showed processive telomerase activity. We were unable to detect dimerization of Tetrahymena telomerase by coprecipitation experiments, by using tags on either the TERT protein or telomerase RNA. Therefore, a majority, if not all, of the recombinant Tetrahymena telomerase in our reconstitution system is present as a monomeric complex. We were also unable to detect dimerization of native telomerase from mating and vegetative Tetrahymena cell extracts. These results demonstrate that Tetrahymena telomerase does not need to dimerize to be active and processive.
Bryan TM, Goodrich KJ, Cech TR
Molecular biology of the cell
2003-12-01 00:00
14
12
4794-804
Animals,Blotting, Northern,Cloning, Molecular,DNA-Binding Proteins,Dimerization,Enzyme Activation,Protein Binding,RNA, Protozoan,Recombinant Proteins,Telomerase,Tetrahymena,DNA-Binding Proteins,RNA, Protozoan,Recombinant Proteins,TERT protein, human,Telomerase
Childrens Medical Research Institute, Westmead, New South Wales 2145, Australia tbryancmriusydeduau
Mol. Biol. Cell
1059-1524
10.1091/mbc.E03-07-0474
E03-07-0474
294
True
13679509
