Open AccessThe C Terminus of the Major Yeast Telomere Binding Protein Rap1p Enhances Telomere Formation
Author(s) -
Anish Ray,
Kurt W. Runge
Publication year - 1998
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.18.3.1284
Subject(s) - telomere , telomerase , telomere binding protein , biology , telomerase rna component , telomerase reverse transcriptase , saccharomyces cerevisiae , microbiology and biotechnology , rna , fungal protein , dna , dna binding protein , genetics , gene , transcription factor
The telomeres of most organisms consist of short repeated sequences that can be elongated by telomerase, a reverse transcriptase complex that contains its own RNA template for the synthesis of telomere repeats. InSaccharomyces cerevisiae , theRAP1 gene encodes the major telomere binding protein Rap1p. Here we use a quantitative telomere formation assay to demonstrate that Rap1p C termini can enhance telomere formation more than 30-fold when they are located at internal sites. This stimulation is distinct from protection from degradation. Enhancement of formation required the gene for telomerase RNA but not Sir1p, Sir2p, Sir3p, Sir4p, Tel1p, or the Rif1p binding site in the Rap1p C terminus. Our data suggest that Rap1p C termini enhance telomere formation by attracting or increasing the activity of telomerase near telomeres. Earlier work suggests that Rap1p molecules at the chromosome terminus inhibit the elongation of long telomeres by blocking the access of telomerase. Our results suggest a model where a balance between internal Rap1p increasing telomerase activity and Rap1p at the termini of long telomeres controlling telomerase access maintains telomeres at a constant length.