In Saccharomyces cerevisiae, the essential gene CDC13 encodes a telomeric single-stranded DNA-binding protein that interacts with Stnlp and Tenlp genetically and physically, and is required for telomere end protection...In Saccharomyces cerevisiae, the essential gene CDC13 encodes a telomeric single-stranded DNA-binding protein that interacts with Stnlp and Tenlp genetically and physically, and is required for telomere end protection and telomere length control. The molecular mechanism by which Tenl participates in telomere length regulation and chromosome end protection remains elusive. In this work, we observed a weak interaction of Cdc13p and Tenlp in a gelfiltration analysis using purified recombinant Cdc13p and Tenlp. Tenlp itself exhibits a weak DNA-binding activity, but enhances the telomeric TG1-3 DNA-binding ability of Cdc13p. Cdc13p is communoprecipitated with Tenlp. In the mutant ten1-55 or ten1-66 cells, the impaired interaction between Tenlp and Cdc13p results in much longer telomeres, as well as a decreased association of Cdc13p with telomeric DNA. Consistently, the Ten1-55 and Ten1-66 mutant proteins fail to stimulate the telomeric DNA-binding activity of Cdc13p in vitro. These results suggest that Tenlp enhances the telomeric DNA-binding activity of Cdc13p to negatively regulate telomere length.展开更多
基金Acknowledgments We thank Ms Lu-Xia Xu for the help in antibody preparation, and other members in the Zhou lab. This work is supported by a Chinese Academy of Sciences-Max Planck Society Professorship, and grants from the National Natural Science Foundation of China （NSFC 30630018） and the Ministry of Science and Technology of China （2007CB914502）.
文摘In Saccharomyces cerevisiae, the essential gene CDC13 encodes a telomeric single-stranded DNA-binding protein that interacts with Stnlp and Tenlp genetically and physically, and is required for telomere end protection and telomere length control. The molecular mechanism by which Tenl participates in telomere length regulation and chromosome end protection remains elusive. In this work, we observed a weak interaction of Cdc13p and Tenlp in a gelfiltration analysis using purified recombinant Cdc13p and Tenlp. Tenlp itself exhibits a weak DNA-binding activity, but enhances the telomeric TG1-3 DNA-binding ability of Cdc13p. Cdc13p is communoprecipitated with Tenlp. In the mutant ten1-55 or ten1-66 cells, the impaired interaction between Tenlp and Cdc13p results in much longer telomeres, as well as a decreased association of Cdc13p with telomeric DNA. Consistently, the Ten1-55 and Ten1-66 mutant proteins fail to stimulate the telomeric DNA-binding activity of Cdc13p in vitro. These results suggest that Tenlp enhances the telomeric DNA-binding activity of Cdc13p to negatively regulate telomere length.
