Pof8 is a La-related protein and a constitutive component of telomerase in fission yeast
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ABSTRACT:
PROVIDER: PRJNA413463 | ENA |
REPOSITORIES: ENA
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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:Telomerase reverse transcriptase (TERT) and the non-coding telomerase RNA subunit (TR) constitute the core of telomerase. Here 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.
| S-EPMC5805746 | biostudies-literature
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:Maturation of human telomerase RNA component from an extended precursor
| PRJNA480915 | ENA
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:We performed a RNA immunoprecipitations experiments using gfp-specific antibodies to precipitate gfp-tagged La proteins from from gfp-La wild type and sumoylation deficient La mutant (K41/200R) cells and found that specific mRNAs are preferentially enriched gfp-La wild type RIPs when compared to sumoylation deficient La mutant (K41/200R) RIPs.
2017-11-22 | GSE102842 | GEO
Project description:La proteins bind the UUU-3’OH sequence found at the 3’-end of nascent RNA polymerase III transcripts, including pre-tRNAs, using a tandem arrangement of a winged-helix fold La motif (LaM) and an adjacent RNA recognition motif (RRM). La binding in diverse species results in protection of the 3’-end from exonucleases, stabilization of the pre-tRNA species and promotion of pre-tRNA folding until the UUU-3’OH containing trailer is endonucleolytically cleaved. Based on sequence conservation in the LaM, the Tetrahymena thermophila protein MLP1 (and related factors in other alveolates) has been hypothesized to function as a genuine La protein, despite the absence of the adjacent RRM found in La proteins of all prior investigated species. We show that MLP1 functions as a genuine La protein in that it binds and affects the processing of pre-tRNAs in T. thermophila and when expressed as a heterologous factor in fission yeast, however, unlike in other examined eukaryotes, depletion of MLP1 results in 3’-trailer stabilization. We also observed that 3’-trailers in T. thermophila are uniquely shortened relative to other examined eukaryotes, and that 5’-leaders in this species have evolved to disfavour pre-tRNA leader/trailer pairing. Our data suggest that the variant MLP1 architecture relative to other genuine La proteins is linked to an altered mechanism of tRNA processing in T. thermophila.
2022-09-13 | GSE199642 | 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: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