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A human-Tetrahymena pseudoknot chimeric telomerase RNA reconstitutes a nonprocessive enzyme in vitro that is defective in telomere elongation 总被引:1,自引:0,他引:1
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Marie-Egyptienne DT Cerone MA Londoño-Vallejo JA Autexier C 《Nucleic acids research》2005,33(17):5446-5457
The phylogenetically-derived secondary structures of telomerase RNAs (TR) from ciliates, yeasts and vertebrates are surprisingly conserved and contain a pseudoknot domain at a similar location downstream of the template. As the pseudoknot domains of Tetrahymena TR (tTR) and human TR (hTR) mediate certain similar functions, we hypothesized that they might be functionally interchangeable. We constructed a chimeric TR (htTR) by exchanging the hTR pseudoknot sequences for the tTR pseudoknot region. The chimeric RNA reconstituted human telomerase activity when coexpressed with hTERT in vitro, but exhibited defects in repeat addition processivity and levels of DNA synthesis compared to hTR. Activity was dependent on tTR sequences within the chimeric RNA. htTR interacted with hTERT in vitro and dimerized predominantly via a region of its hTR backbone, the J7b/8a loop. Introduction of htTR in telomerase-negative cells stably expressing hTERT did not reconstitute an active enzyme able to elongate telomeres. Thus, our results indicate that the chimeric RNA reconstituted a weakly active nonprocessive human telomerase enzyme in vitro that was defective in telomere elongation in vivo. This suggests that there may be species-specific requirements for pseudoknot functions. 相似文献
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Two independent regions of human telomerase reverse transcriptase are important for its oligomerization and telomerase activity. 总被引:7,自引:0,他引:7
Kuniaki Arai Kenkichi Masutomi Shilagardy Khurts Shuichi Kaneko Kenichi Kobayashi Seishi Murakami 《The Journal of biological chemistry》2002,277(10):8538-8544
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Etheridge KT Banik SS Armbruster BN Zhu Y Terns RM Terns MP Counter CM 《The Journal of biological chemistry》2002,277(27):24764-24770
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