Pseudoknot structures with conserved base triples in telomerase RNAs of ciliates
| Autor: | Kinneret Shefer, Yehuda Tzfati, Nikolai B. Ulyanov, Thomas L. James |
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| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular Telomerase Tetrahymenina viruses Biology Conserved sequence 03 medical and health sciences Telomerase RNA component Models Information and Computing Sciences Genetics Animals Telomerase reverse transcriptase Ciliophora Conserved Sequence 030304 developmental biology Kluyveromyces lactis 0303 health sciences Base Sequence 030302 biochemistry & molecular biology Molecular RNA Biological Sciences biology.organism_classification Telomere Protozoan Nucleic Acid Conformation Pseudoknot Environmental Sciences RNA Protozoan Developmental Biology |
| Zdroj: | Nucleic Acids Research Nucleic acids research, vol 35, iss 18 |
| ISSN: | 1362-4962 0305-1048 |
| DOI: | 10.1093/nar/gkm660 |
| Popis: | Telomerase maintains the integrity of telomeres, the ends of linear chromosomes, by adding G-rich repeats to their 3'-ends. Telomerase RNA is an integral component of telomerase. It contains a template for the synthesis of the telomeric repeats by the telomerase reverse transcriptase. Although telomerase RNAs of different organisms are very diverse in their sequences, a functional non-template element, a pseudoknot, was predicted in all of them. Pseudoknot elements in human and the budding yeast Kluyveromyces lactis telomerase RNAs contain unusual triple-helical segments with AUU base triples, which are critical for telomerase function. Such base triples in ciliates have not been previously reported. We analyzed the pseudoknot sequences in 28 ciliate species and classified them in six different groups based on the lengths of the stems and loops composing the pseudoknot. Using miniCarlo, a helical parameter-based modeling program, we calculated 3D models for a representative of each morphological group. In all cases, the predicted structure contains at least one AUU base triple in stem 2, except for that of Colpidium colpoda, which contains unconventional GCG and AUA triples. These results suggest that base triples in a pseudoknot element are a conserved feature of all telomerases. |
| Databáze: | OpenAIRE |
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