Mechanisms of nucleotide selection by telomerase
Telomerase extends telomere sequences at chromosomal ends to protect genomic DNA. During this process it must select the correct nucleotide from a pool of nucleotides with various sugars and base pairing properties, which is critically important for the proper capping of telomeric sequences by shelt...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2020-06-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/55438 |
| _version_ | 1811180536324947968 |
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| author | Matthew A Schaich Samantha L Sanford Griffin A Welfer Samuel A Johnson Thu H Khoang Patricia L Opresko Bret D Freudenthal |
| author_facet | Matthew A Schaich Samantha L Sanford Griffin A Welfer Samuel A Johnson Thu H Khoang Patricia L Opresko Bret D Freudenthal |
| author_sort | Matthew A Schaich |
| collection | DOAJ |
| description | Telomerase extends telomere sequences at chromosomal ends to protect genomic DNA. During this process it must select the correct nucleotide from a pool of nucleotides with various sugars and base pairing properties, which is critically important for the proper capping of telomeric sequences by shelterin. Unfortunately, how telomerase selects correct nucleotides is unknown. Here, we determined structures of Tribolium castaneum telomerase reverse transcriptase (TERT) throughout its catalytic cycle and mapped the active site residues responsible for nucleoside selection, metal coordination, triphosphate binding, and RNA template stabilization. We found that TERT inserts a mismatch or ribonucleotide ~1 in 10,000 and ~1 in 14,000 insertion events, respectively. At biological ribonucleotide concentrations, these rates translate to ~40 ribonucleotides inserted per 10 kilobases. Human telomerase assays determined a conserved tyrosine steric gate regulates ribonucleotide insertion into telomeres. Cumulatively, our work provides insight into how telomerase selects the proper nucleotide to maintain telomere integrity. |
| first_indexed | 2024-04-11T09:04:42Z |
| format | Article |
| id | doaj.art-4e22fc7309344751ac64f8a5732134ad |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-11T09:04:42Z |
| publishDate | 2020-06-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-4e22fc7309344751ac64f8a5732134ad2022-12-22T04:32:40ZengeLife Sciences Publications LtdeLife2050-084X2020-06-01910.7554/eLife.55438Mechanisms of nucleotide selection by telomeraseMatthew A Schaich0https://orcid.org/0000-0001-6771-5623Samantha L Sanford1Griffin A Welfer2Samuel A Johnson3Thu H Khoang4Patricia L Opresko5Bret D Freudenthal6https://orcid.org/0000-0003-1449-4710Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, United StatesDepartment of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and UPMC Hillman Cancer Center, Pittsburgh, United StatesDepartment of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, United StatesDepartment of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and UPMC Hillman Cancer Center, Pittsburgh, United StatesDepartment of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, United StatesDepartment of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, and UPMC Hillman Cancer Center, Pittsburgh, United StatesDepartment of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, United States; Department of Cancer Biology, University of Kansas Medical Center, Kansas City, United StatesTelomerase extends telomere sequences at chromosomal ends to protect genomic DNA. During this process it must select the correct nucleotide from a pool of nucleotides with various sugars and base pairing properties, which is critically important for the proper capping of telomeric sequences by shelterin. Unfortunately, how telomerase selects correct nucleotides is unknown. Here, we determined structures of Tribolium castaneum telomerase reverse transcriptase (TERT) throughout its catalytic cycle and mapped the active site residues responsible for nucleoside selection, metal coordination, triphosphate binding, and RNA template stabilization. We found that TERT inserts a mismatch or ribonucleotide ~1 in 10,000 and ~1 in 14,000 insertion events, respectively. At biological ribonucleotide concentrations, these rates translate to ~40 ribonucleotides inserted per 10 kilobases. Human telomerase assays determined a conserved tyrosine steric gate regulates ribonucleotide insertion into telomeres. Cumulatively, our work provides insight into how telomerase selects the proper nucleotide to maintain telomere integrity.https://elifesciences.org/articles/55438T. castaneumtelomeraseribonucleotidereverse transcriptasefidelity |
| spellingShingle | Matthew A Schaich Samantha L Sanford Griffin A Welfer Samuel A Johnson Thu H Khoang Patricia L Opresko Bret D Freudenthal Mechanisms of nucleotide selection by telomerase eLife T. castaneum telomerase ribonucleotide reverse transcriptase fidelity |
| title | Mechanisms of nucleotide selection by telomerase |
| title_full | Mechanisms of nucleotide selection by telomerase |
| title_fullStr | Mechanisms of nucleotide selection by telomerase |
| title_full_unstemmed | Mechanisms of nucleotide selection by telomerase |
| title_short | Mechanisms of nucleotide selection by telomerase |
| title_sort | mechanisms of nucleotide selection by telomerase |
| topic | T. castaneum telomerase ribonucleotide reverse transcriptase fidelity |
| url | https://elifesciences.org/articles/55438 |
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