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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Bulged Stem Tethers Est1p To Telomerase Rna In Budding Yeast, Anita G. Seto, April J. Livengood, Yehuda Tzfati, Elizabeth H. Blackburn, Thomas R. Cech Nov 2002

A Bulged Stem Tethers Est1p To Telomerase Rna In Budding Yeast, Anita G. Seto, April J. Livengood, Yehuda Tzfati, Elizabeth H. Blackburn, Thomas R. Cech

Chemistry & Biochemistry Faculty Contributions (1986-2018)

It is well established that the template for telomeric DNA synthesis is provided by the RNA subunit of telomerase; however, the additional functions provided by most of the rest of the RNA (>1000 nucleotides in budding yeast) are largely unknown. By alignment of telomerase RNAs of Saccharomyces cerevisiae and sixKluyveromycesspecies followed by mutagenesis of the S. cerevisiae RNA, we found a conserved region that is essential for telomere maintenance. Phylogenetic analysis and computer folding revealed that this region is conserved not only in primary nucleotide sequence but also in secondary structure. A common bulged-stem structure was predicted in ...


Human Pot1 (Protection Of Telomeres) Protein: Cytolocalization Gene Structure, And Alternative Splicing, Peter Baumann, Elaine Podell, Thomas R. Cech Nov 2002

Human Pot1 (Protection Of Telomeres) Protein: Cytolocalization Gene Structure, And Alternative Splicing, Peter Baumann, Elaine Podell, Thomas R. Cech

Chemistry & Biochemistry Faculty Contributions (1986-2018)

Fission yeast Pot1 (protection of telomeres) is a single-stranded telomeric DNA binding protein with a critical role in ensuring chromosome stability. A putative human homolog (hPot1) was previously identified, based on moderate sequence similarity with fission yeast Pot1 and telomere end-binding proteins from ciliated protozoa. Using indirect immunofluorescence, we show here that epitope-tagged hPot1 localizes to telomeres in interphase nuclei of human cells, consistent with a direct role in telomere end protection. The hPOT1 gene contains 22 exons, most of which are present in all cDNAs examined. However, four exons are subject to exon skipping in some transcripts, giving rise ...


In Vivo Selection Of Better Self-Splicing Introns In E. Coli: The Role Of The P1 Extension Helix Of The Tetrahymena Intron, Feng Guo, Thomas R. Cech May 2002

In Vivo Selection Of Better Self-Splicing Introns In E. Coli: The Role Of The P1 Extension Helix Of The Tetrahymena Intron, Feng Guo, Thomas R. Cech

Chemistry & Biochemistry Faculty Contributions (1986-2018)

In vivo selection was used to improve the activity of the Tetrahymena pre-rRNA self-splicing intron in the context of heterologous exons. The intron was engineered into a kanamycin nucleotidyltransferase gene, with the pairing between intron bases and the 5' and 3' splice sites maintained. The initial construct failed to confer kanamycin resistance on Escherichia coli, although the pre-mRNA was active in splicing in vitro. Random mutation libraries were constructed to identify active intron variants in E. coli. All the active mutants sequenced contained mutations disrupting a base-paired region above the paired region P1 (referred to as the P1 extension region ...