Yeast Genetics and Molecular Biology 1998
College Park, Maryland
August 1998


Name: Stavenhagen, Jeffrey
Mailing Address: Biology, University of Dayton, 300 College Park, Dayton, OH 45469, USA
Email Address: stavenha@neelix.udayton.edu
Phone and Fax numbers: 937-229-2587, 937-229-2021

355

Charaterization of telomeric recombination in Saccharomyces cerevisiae .


J. B. Stavenhagen (1) , V. A. Zakian (2)
(1) Department of Biology, University of Dayton, Dayton, OH, 45469; (2) Princeton U.

A novel C 1-3 A direct repeat recombination assay has been established to measure telomeric recombination. Direct repeat recombination between C 1-3 A direct repeats is blocked near telomeres. In contrast recombination between control substrates, direct repeats of either C 4 A 2 or a unique sequence, is not affected by telomere proximity. The inhibition is not under the same control as telomere position effect (TPE) as it is both sequence specific and mutations in genes essential for TPE do not alleviate the telomeric repression on recombination. The C 1-3 A specific repression is eliminated in cells that over express the telomere binding protein, Rap1, a condition that also increases recombination between yeast telomeric direct repeats at internal positions on the chromosome. We propose that the repression of C 1-3 A direct repeat recombination occurs through the action of a telomere specific end-binding protein. We have used the direct repeat assay in a mutant screen to look for mutations that specifically increase C 1-3 A direct repeat recombination. Mutagenesis was performed and ~6000 colonies were screened for hyper-recombination. We identified 6 t elomere h yper- r ecombination ( thr ) mutants that show increased C 1-3 A direct repeat recombination. Fluctuation analysis determined that the rates of recombination of the thr mutants varied from 6-75-fold over wild type rates of recombination. Preliminary data suggest that the effect on recombination is specific to C 1-3 A direct repeats. At least one of the thr mutants shows a telomere length phenotype. Further characterization and cloning of the thr mutants will provide insight into the role of recombination in telomere metabolism.


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