Biogenesis of telomerase RNA in homeostasis and disease
Abstract/Contents
- Abstract
- Disruptions in RNA metabolism and errors in RNA processing are increasingly linked to a diverse set of human diseases. Telomerase, the ribonucleoprotein that extends telomeres to prevent replication-dependent chromosomal shortening, is composed of the reverse transcriptase TERT and the noncoding RNA (ncRNA) telomerase RNA component (hTR). Defects in hTR or in any of the protein cofactors required for hTR biogenesis precipitate telomere shortening and the stem cell disorder dyskeratosis congenita. Despite the critical importance of hTR in telomere homeostasis, the events surrounding hTR transcription, 3' end formation, and post-transcriptional regulation remain poorly understood. To interrogate the hTR biogenesis pathway in an unbiased kinetic fashion, we developed nascent 3' RNAend --Seq, which enabled us to isolate early hTR precursors and measure processing rates in vivo under different genetic conditions. We found that hTR is transcribed as an extended molecule with a short genomically encoded tail. These extended hTR precursors convert to the mature hTR species with delayed kinetics compared to related small ncRNAs. The hTR precursors can be oligoadenylated shortly after transcription by the poly(A)polymerase PAPD5 and can be deadenylated by the disease-associated enzyme Poly(A)ribonuclease (PARN). The relative activity of these two enzymes and the extent of of hTR precursors sets the maturation rate of hTR. In the absence of PARN, oligoadenylated hTR precursors stall and are degraded, causing overall hTR loss and telomere shortening. However, in the absence of both PARN and PAPD5, hTR precursor maturation is normalized and telomere lengths are maintained. We found that the H/ACA domain of hTR together with the RNA-binding protein dyskerin could direct formation of the hTR 3' end, recruit poly(A)polymerase activity, and confer sensitivity to regulation by oligoadenylation. A screen for additional enzymes involved in hTR 3' end formation revealed the DEDDh 3'-5' RNA exonuclease ISG20L2, which works together with PARN to promote maturation of the hTR 3' end and ensure accumulation of telomerase. These data reveal that mature hTR is generated through a feedforward circuit in which post-transcriptional oligoadenylation controls RNA maturation kinetics. Perturbations of hTR maturation rates read out into changes in steady-state telomerase levels and telomere length. Alterations in RNA maturation kinetics may prove to contribute to the mechanisms of other RNA based human diseases.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Roake, Caitlin Marie |
|---|---|
| Degree supervisor | Artandi, Steven E |
| Thesis advisor | Artandi, Steven E |
| Thesis advisor | Attardi, Laura |
| Thesis advisor | Chua, Katrin Faye |
| Degree committee member | Attardi, Laura |
| Degree committee member | Chua, Katrin Faye |
| Associated with | Stanford University, Cancer Biology Program |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Caitlin Marie Roake. |
|---|---|
| Note | Submitted to the Cancer Biology Program. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/nz642bn7013 |
Access conditions
- Copyright
- © 2021 by Caitlin Marie Roake
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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