Identification of Protein Components of Yeast Telomerase
Annual rept. 1 Sep 1999-31 Aug 2000
PRINCETON UNIV NJ
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Telomere length is tightly regulated in Saccharoinyces. This lengthening is dependent on TLcl, which encodes the RNA component of telomerase hut independent of RAD52, which encodes a protein required for most recombination events in mitotic yeast cells. Most cells lacking yeast telomerase die but survivors arise by RAD52 dependent events the majority of these survivors have tandem duplications of the sub-telomeric y element. However, about 10 of the survivors have a different telomeric structure, very long tracts of C1-3ATG1-3 DNA, with some telomeres being as much as 12 kb longer than telomeres in wild type cells. This pattern of exceptionally long telomeres is similar to that seen in human cell lines and tumors that maintain telomeric DNA without expressing telomerase. The maintenance of these long telomeres requires the continuous presence of Rad52p. However, even in the presence of Rad52p, these long telomeres steadily shorten, suggesting that even in cells that maintain their telomeres by telomere-telomere recombination, recombinational mediated telomere lengthening is relatively rare.
- Medicine and Medical Research