Maturation of human telomerase RNA component from an extended precursor
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ABSTRACT:
PROVIDER: PRJNA480915 | ENA |
REPOSITORIES: ENA
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Project description:Here, we develop nascent RNAend-Seq, in which we isolate nascent RNA and sequence the 3' ends of RNA precursors. Using a pulse-chase experimental design, we follow extended precursors of the telomerase RNA component (hTR) and show that the mature telomerase RNA derives from these species with slow kinetics compared to other small non-coding RNAs. The human disease causing gene PARN further delays maturation of the hTR precursor in PARN- mutant cancer cell lines. Disruption of the poly(A)polymerase PAPD5 in PARN-mutant cells restores normal processing kinetics and levels of mature hTR. Unexpectedly, neither PARN nor PAPD5 is required for hTR processing. Instead, PAPD5 and PARN set the hTR maturation rate by controlling precursor adenylation.
2019-03-28 | GSE117054 | GEO
Project description:Mutations in the poly(A) ribonuclease (PARN) gene cause telomere diseases including familial idiopathic pulmonary fibrosis (IPF) and dyskeratosis congenita (DC)1,2, but how PARN deficiency impacts telomere maintenance is unclear. Here, using somatic cells and induced pluripotent stem (iPS) cells from DC patients with PARN mutations, we show that PARN is required for the 3′ end maturation of the telomerase RNA component (TERC). Patient cells as well as immortalized cells in which PARN is disrupted show decreased levels of TERC. Deep sequencing of TERC RNA 3′ termini reveals that PARN is required for removal of posttranscriptionally acquired oligo(A) tails that target nuclear RNAs for degradation. Diminished TERC levels and the increased oligo(A) forms of TERC are normalized by restoring PARN, which is limiting for TERC maturation in cells. Our results reveal a novel role for PARN in the biogenesis of TERC, and provide a mechanism linking PARN mutations to telomere diseases. mRNA sequencing of fibroblasts, induced pluripotent stem cells, and 293 cell line.
2015-09-08 | E-GEOD-71709 | biostudies-arrayexpress
Project description:Mutations in the poly(A) ribonuclease (PARN) gene cause telomere diseases including familial idiopathic pulmonary fibrosis (IPF) and dyskeratosis congenita (DC)1,2, but how PARN deficiency impacts telomere maintenance is unclear. Here, using somatic cells and induced pluripotent stem (iPS) cells from DC patients with PARN mutations, we show that PARN is required for the 3′ end maturation of the telomerase RNA component (TERC). Patient cells as well as immortalized cells in which PARN is disrupted show decreased levels of TERC. Deep sequencing of TERC RNA 3′ termini reveals that PARN is required for removal of posttranscriptionally acquired oligo(A) tails that target nuclear RNAs for degradation. Diminished TERC levels and the increased oligo(A) forms of TERC are normalized by restoring PARN, which is limiting for TERC maturation in cells. Our results reveal a novel role for PARN in the biogenesis of TERC, and provide a mechanism linking PARN mutations to telomere diseases.
2015-09-08 | GSE71709 | GEO
Project description:Telomerase reverse transcriptase (TERT) and the noncoding telomerase RNA (TR) subunit constitute the core of telomerase. We now report that the putative F-box protein Pof8 is also a constitutive component of active telomerase in fission yeast. Pof8 functions in a hierarchical assembly pathway by promoting the binding of the Lsm2-8 complex to telomerase RNA, which in turn promotes binding of the catalytic subunit. Loss of Pof8 reduces TER1 stability, causes a severe assembly defect and results in critically short telomeres. Structure profile searches identified similarities between Pof8 and telomerase subunits from ciliated protozoa, making Pof8 next to TERT the most widely conserved telomerase subunits identified to date.
2018-02-09 | GSE104672 | GEO
Project description:Human telomerase assembly is a highly dynamic process. Using biochemical approaches, we found that LARP3 and LARP7/MePCE are involved in the early stage and that their binding to hTR is destabilized when the mature hTR is produced. LARP3 plays a negative role in preventing the processing of the 3′-extended long (exL) form and binding of LARP7 and MePCE. Interestingly, the tertiary structure of the exL form prevents LARP3 binding and facilitates hTR biogenesis. Supporting this process, LARP3 at low levels promotes hTR maturation, increases telomerase activity, and elongates telomeres. LARP7 and MePCE knockdown inhibits the conversion of the 3′-extended short (exS) form into mature hTR and the cytoplasmic accumulation of hTR, resulting in telomere shortening. Our data suggest that LARP3 and LARP7/MePCE mediate the processing of hTR precursors and thus control the production of functional telomerase.
2024-07-25 | GSE262590 | GEO
Project description:Single-strand selective uracil DNA-glycosylase (SMUG1) associates with the DKC1-H/ACA ribonucleoprotein complex, which is essential for telomerase biogenesis. We show herein, that SMUG1 interacts with the telomerase RNA component, hTERC, and is required for co-transcriptional processing of the nascent transcript towards mature hTERC. We demonstrate that SMUG1 regulates the presence of base modifications between the CR4/CR5 region and the H-box situated towards the 3´-end of hTERC. Increased levels of hTERC base modifications are accompanied by reduced DKC1 binding. Loss of SMUG1 leads to an imbalance between mature hTERC and its processing intermediates, leading to the accumulation of 3´-polyadenylated and 3´-extended intermediates that are degraded in an EXOSC10-independent RNA degradation pathway. Consequently, SMUG1-deprived cells, present telomerase deficiency leading to impaired bone marrow proliferation in SMUG1-knockout mice.
2019-08-11 | GSE116580 | GEO
Project description:Ribonucleoprotein enzymes require specific and dynamic conformations of their RNA constituents for regulated catalysis. Telomerase RNA components (TRs) rely on two conserved domains, a pseudoknot/template sequence and a three-way junction (CR4/5), each of which binds the telomerase reverse transcriptase protein (TERT). Vertebrate TRs evolved a third element, the H/ACA domain, involved in assembly and trafficking of telomerase through binding telomerase cofactors, dyskerin and TCAB1, respectively. Here, we show that telomerase unexpectedly requires TCAB1 for enzyme catalysis and for shaping the conformation of the TR CR4/5 domain. Human and mouse cells lacking TCAB1 exhibit a marked reduction in telomerase activity, but show no defect in enzyme assembly. Instead, loss of TCAB1 causes specific unfolding of critical RNA helices in TR CR4/5 required for catalysis, and impairs TR-TERT association. CR4/5 mutations derived from patients with the telomere disorder dyskeratosis congenita phenocopy the loss of enzyme activity and disruption of TERT binding observed with TCAB1 deletion. These findings show that the H/ACA element acquired by telomerase during vertebrate evolution serves an unanticipated role in controlling folding of the essential TR CR4/5 domain, facilitating optimal TERT engagement and enabling telomerase catalysis through the action of TCAB1 protein tethered at the H/ACA domain.
2018-06-24 | GSE97486 | GEO
Project description:Human telomerase RNA (hTR) is transcribed as a precursor that is then posttranscriptionally modified and processed. A fraction of the transcripts is oligoadenylated by TRAMP and either processed into the mature hTR or degraded by the exosome. Here, we characterize the processing of 3’ extended forms of varying length by PARN and RRP6. We show that tertiary RNA interactions unique to the longer precursor forms favor RNA degradation, whereas H/ACA RNP assembly stimulates productive processing. Interestingly, the H/ACA complex actively promotes processing in addition to protecting the mature 3’ end. Processing occurs in two steps with longer forms being trimmed by RRP6 and shorter forms being preferentially processed by PARN. These results reveal how RNA structure and RNP assembly affect the kinetics of processing and degradation and ultimately determine the amount of functional telomerase produced in cells.
2018-12-26 | GSE111081 | GEO
Project description:Genetic lesions that reduce telomerase cause a range of incurable diseases including dyskeratosis congenita (DC) and pulmonary fibrosis (PF), and restoring telomere length in these patients would be curative. Ectopic expression of telomerase reverse transcriptase (TERT) risks cellular immortalization, and how to target telomerase in stem cells throughout the body remains unclear. Here we describe a successful screen for small molecules that augment TERC, the non-coding telomerase RNA component, and thereby specifically elongate telomeres in stem cells. PAPD5 is a non-canonical polymerase that oligo-adenylates and destabilizes TERC. Using a high-throughput screen we identify BCH001, a specific PAPD5 inhibitor that decreases TERC 3′- oligo(A) tailing and increases telomerase activity and telomere length by thousands of nucleotides in DC patient induced pluripotent stem cells (iPSCs). BCH001 does not result in immortalization or telomere elongation in somatic cells which lack TERT, establishing a favorable safety profile. When human hematopoietic stem and progenitor cells (HSPCs) engineered by CRISPR-Cas9 to carry PARN mutations that cause DC and PF are xenotransplanted into immunodeficient mice, oral treatment with PAPD5 inhibitors rescues TERC 3′-end maturation and telomere length. Our data demonstrate telomere restoration in human stem cells in vivo using small molecules.
2020-04-21 | GSE144986 | GEO
Project description:Primary telomerase RNA transcripts are processed into shorter mature forms that assemble into a complex with the catalytic subunit and provide the template for telomerase activity. In diverse fungi telomerase RNA 3â end processing involves a single cleavage reaction by the spliceosome akin to the first step of splicing. Longer forms of human telomerase RNA (hTR) have been reported, but how the mature form of precisely 451 nucleotides is generated is still unknown. We now show that the splicing inhibitor isoginkgetin causes accumulation of long hTR transcripts, but find no evidence for a direct role for splicing in hTR processing. Instead, isoginkgetin mimics the effects of inhibiting the RNA exosome. Depletion of exosome components and accessory factors reveals functions for the cap binding complex (CBC) and the nuclear exosome targeting (NEXT) complex in hTR turnover. Whereas longer transcripts are predominantly degraded, shorter precursor RNAs are oligo-adenylated by TRF4-2 and either processed by poly (A) specific ribonuclease (PARN) or degraded by the exosome. Our results reveal that hTR biogenesis involves a kinetic competition between RNA processing and quality control pathways and suggest new treatment options for dyskeratosis congenita caused by mutations in RNA processing factors. We cloned and sequenced 3â ends by RLM-RACE coupled with high-throughput sequencing to gain further insights into hTR processing.
2015-11-25 | E-GEOD-73776 | biostudies-arrayexpress