RNA ligation precedes U6 snRNA/LINE-1 retrotransposition
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ABSTRACT:
PROVIDER: PRJNA486226 | ENA |
REPOSITORIES: ENA
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Project description:RNA ligation precedes U6 snRNA/LINE-1 retrotransposition
| PRJNA1273211 | ENA
Project description: Not available
| S-EPMC6789731 | biostudies-literature
Project description:MMARY THUMPD2 installs N2-methylguanosine (m2G) at position 72 of the U6 snRNA, and this modification, which lies at the catalytic core of the spliceosome, is required for efficient splicing of weak splice sites. However, when during the U6 lifecycle this modification is installed and what features of the U6 snRNA and THUMPD2 are required for methylation of G72 remain elusive. Here, we show that U6 associated with THUMPD2 is not oligouridylated and that late-acting U6 snRNP biogenesis factors are enriched with THUMPD2. We map RNA crosslinking sites within the N-terminal region and C-terminal Rossman-fold methyltransferase domain of THUMPD2, and show the requirement of these domains for THUMPD2 interaction with U6 in cells. Using a newly developed m2G-sensitive deoxyribozyme to monitor U6-m2G72 levels in cellular RNAs, we demonstrate the requirement of SAM binding and interaction with the THUMPD2 cofactor TRMT112 for efficient methylation. Our data further reveal that 2’-O-methylation of C62, C63 and A70 do not increase the affinity of THUMPD2 for the U6 internal stem-loop (ISL), but enhance m2G methylation of G72. Nucleotide substitutions within the loop region of the ISL that extend the stem similarly increase m2G72 installation, demonstrating that the stability of the ISL is key for methylation by THUMPD2. Together these results provide a new layer of understanding of how an RNA modification that fine-tunes pre-mRNA splicing is introduced.
2026-05-25 | PXD053619 | Pride
Project description:THUMPD2 installs N2-methylguanosine (m2G) at position 72 of the U6 snRNA, and this modification, which lies at the catalytic core of the spliceosome, is required for efficient splicing of weak splice sites. However, when during the U6 lifecycle this modification is installed and what features of the U6 snRNA and THUMPD2 are required for methylation of G72 remain elusive. Here, we show that U6 associated with THUMPD2 is not oligouridylated and that late-acting U6 snRNP biogenesis factors are enriched with THUMPD2. We map RNA crosslinking sites within the N-terminal region and C-terminal Rossman-fold methyltransferase domain of THUMPD2, and show the requirement of these domains for THUMPD2 interaction with U6 in cells. Using a newly developed m2G-sensitive deoxyribozyme to monitor U6-m2G72 levels in cellular RNAs, we demonstrate the requirement of SAM binding and interaction with the THUMPD2 cofactor TRMT112 for efficient methylation. Our data further reveal that 2’-O-methylation of C62, C63 and A70 do not increase the affinity of THUMPD2 for the U6 internal stem-loop (ISL), but enhance m2G methylation of G72. Nucleotide substitutions within the loop region of the ISL that extend the stem similarly increase m2G72 installation, demonstrating that the stability of the ISL is key for methylation by THUMPD2. Together these results provide a new layer of understanding of how an RNA modification that fine-tunes pre-mRNA splicing is introduced.
2026-05-25 | PXD053510 | Pride
Project description:The post-transcriptional maturation of U6 snRNA 3′-end is important for spliceosomal assembly and RNA splicing, and is catalyzed by sequential enzymatic activities of TUT1 and USB1, that is, an oligo(U) tail is first added by TUT1 to the freshly transcribed U6 snRNA, and then trimmed by USB1 to generate mature U6 snRNA. However, biallelic inactivation of TUT1 or USB1 is linked to distinct human developmental disorders, and their physiological functions remain unknown. Here, using multiple genetically engineered mouse models, we show that Tut1, but unexpectedly not Usb1, is essential for the maintenance of the epiblast and neural stem cells in vivo. Loss of Tut1 weakens the interactions between essential splicing factors and U6 snRNA, causes defective RNA splicing, and triggers massive DNA damage and subsequent cell death. Importantly, cell death can be prevented by recombinant U6 snRNA containing an oligo(U) tail. These results challenge the current model of U6 snRNA 3′-end maturation and function. We propose that TUT1 is an essential U6 snRNA 3′-end maturation or repair factor, and discuss the implications of these results for understanding the etiologies of TUT1- and USB1-related human disorders.
2026-06-03 | GSE305663 | GEO
Project description:Mpn1 proteins are evolutionarily conserved exonucleases that modify spliceosomal U6 small nuclear RNAs (snRNAs) post-transcriptionally. Mutations in the human MPN1 gene are associated to the genodermatosis Clericuzio-type poikiloderma with neutropenia (PN). Mpn1 deficiency leads to aberrant U6 3M-bM-^@M-^Y end processing and accelerated U6 decay through unknown molecular mechanisms. Here we show that in mpn1M-NM-^T fission yeast cells U6 is barely bound by the protective Lsm2-8 complex, undergoes extensive oligoadenylation and is degraded by the nuclear RNA exonuclease Rrp6 independently of the poly(A) polymerase Cid14/Trf4. Mpn1 processes U6 in a spliceosome-dependent manner, as mutant U6 molecules that fail to join the spliceosome are not substrates for Mpn1. Moreover, human U6atac, the U6-like snRNA of the minor spliceosome, is a novel substrate for hMpn1. We unveil mechanistic details of a new U6 degradation pathway and further corroborate the notion that inefficient canonical and minor pre-mRNA splicing promotes PN. the 3' termini of U6 or tagged-U6 species from the indicated mutant cells were compared to wt yeast strain
2014-08-08 | E-GEOD-60195 | biostudies-arrayexpress
Project description: Not available
| S-EPMC4476161 | biostudies-literature
Project description:The post-transcriptional maturation of U6 snRNA 3′-end is important for spliceosomal assembly and RNA splicing, and is catalyzed by sequential enzymatic activities of TUT1 and USB1, that is, an oligo(U) tail is first added by TUT1 to the freshly transcribed U6 snRNA, and then trimmed by USB1 to generate mature U6 snRNA. However, biallelic inactivation of TUT1 or USB1 is linked to distinct human developmental disorders, and their physiological functions remain unknown. Here, using multiple genetically engineered mouse models, we show that Tut1, but unexpectedly not Usb1, is essential for the maintenance of the epiblast and neural stem cells in vivo. Loss of Tut1 weakens the interactions between essential splicing factors and U6 snRNA, causes defective RNA splicing, and triggers massive DNA damage and subsequent cell death. Importantly, cell death can be prevented by recombinant U6 snRNA containing an oligo(U) tail. These results challenge the current model of U6 snRNA 3′-end maturation and function. We propose that TUT1 is an essential U6 snRNA 3′-end maturation or repair factor, and discuss the implications of these results for understanding the etiologies of TUT1- and USB1-related human disorders.
2026-06-03 | GSE305664 | GEO
Project description:Maintenance of the intracellular levels of the methyl donor S-adenosylmethionine (SAM) is essential for a wide variety of biological processes. We demonstrate that the N6-adenosine methyltransferase METTL16 regulates expression of MAT2A, which encodes the only SAM synthetase expressed in most cells. Upon SAM depletion by methionine starvation, cells induce MAT2A expression by enhanced splicing of a retained intron. Induction requires METTL16 and its methylation substrate, a vertebrate conserved hairpin (hp1) in the MAT2A 3´ UTR. Increasing METTL16 occupancy on the MAT2A 3´ UTR is sufficient to induce efficient splicing. We propose that under SAM-limiting conditions, METTL16 occupancy on hp1 increases due to inefficient enzymatic turnover, which in turn promotes MAT2A splicing. Interestingly, human and S. pombe METTL16 methylate the U6 spliceosomal snRNA at a sequence identical to hp1. These observations suggest that the conserved U6 snRNA methyltransferase evolved an additional function in vertebrates to regulate SAM homeostasis.
2017-05-18 | GSE90914 | GEO