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Expression of a RecQ helicase homolog af ... ission yeast lacking telomerase
Expression of a RecQ helicase homolog affects progression through crisis in fission yeast lacking telomerase.
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RecQ helicases play roles in telomere maintenance in cancerous human cells using the alternative lengthening of telomeres mechanism and in budding yeast lacking telomerase. Fission yeast lacking the catalytic subunit of telomerase (trt1(+)) up-regulate the expression of a previously uncharacterized sub-telomeric open reading frame as survivors emerge from crisis. Here we show that this open reading frame encodes a protein with homology to RecQ helicases such as the human Bloom's and Werner's syndrome proteins and that copies of the helicase gene are present on multiple chromosome ends. Characterization of the helicase transcript revealed a 7.6-kilobase RNA that was associated with polyribosomes, suggesting it is translated. A 3.6-kilobase domain of the helicase gene predicted to encode the region with catalytic activity was cloned, and both native and mutant forms of this domain were overexpressed in trt1(-) cells as they progressed through crisis. Overexpression of the native form caused cells to recover from crisis earlier than cells with a vector-only control, whereas overexpression of the mutant form caused delayed recovery from crisis. Taken together, the sequence homology, functional analysis, and site-directed mutagenesis indicate that the protein is likely a second fission yeast RecQ helicase (in addition to Rqh1) that participates in telomere metabolism during crisis. These results strengthen the notion that in multiple organisms RecQ helicases contribute to survival after telomere damage.
Mandell JG, Goodrich KJ, Bähler J, Cech TR
The Journal of biological chemistry
2005-02-18 00:00
280
7
5249-57
Adenosine Triphosphatases,Amino Acid Sequence,Chromosomes, Fungal,Cloning, Molecular,DNA Helicases,Gene Expression Regulation, Fungal,Humans,Molecular Sequence Data,Open Reading Frames,Phylogeny,Polyribosomes,RNA, Fungal,RNA, Messenger,RecQ Helicases,Schizosaccharomyces,Schizosaccharomyces pombe Proteins,Sequence Homology, Amino Acid,Telomerase,Telomere,RNA, Fungal,RNA, Messenger,Schizosaccharomyces pombe Proteins,Telomerase,Adenosine Triphosphatases,DNA Helicases,RECQL protein, human,RecQ Helicases
Department of Chemistry and Biochemistry and Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309-0215, USA
J. Biol. Chem.
NIGMS GM28039
0021-9258
10.1074/jbc.M412756200
M412756200
188
True
15591066
