Deletions of singular U1 snRNA gene significantly interfere with transcription and 3'-end mRNA formation rather than pre-mRNA splicing
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ABSTRACT:
PROVIDER: PRJNA936603 | ENA |
REPOSITORIES: ENA
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Project description:To investigate the functions of each singular copy of snRNA genes in Drosophila melanogaster, we focused on the U1 snRNA and systematically investigated all the five Drosophila U1 genes. We constructed two series of U1-gene strains, one is transgenic strains of U1 promoter-driven gfp that allows for detection of each U1-gene’s expression in various developmental stages and tissues, the other is the CRISPR/Cas9-mediated precise U1-gene deletion strains that allows for investigation of phenotypes and effects on multiple RNA processing steps, including transcription, splicing and 3'-end formation. Further in vitro pulldown assay reveal the Drosophila U1 variants have different activity in binding with Sm proteins.
2023-02-19 | GSE225604 | GEO
Project description:Small nuclear RNAs (snRNAs) are structural and functional cores of the spliceosome. In metazoan genomes, each snRNA has multiple copies/variants, up to hundreds in mammals. However, the expressions and functions of each copy/variant in one organism have not been systematically studied. Focus on U1 snRNA genes, we investigated all five copies in Drosophila melanogaster using two series of constructed strains. Analyses of transgenic flies that each have a U1 promoter-driven gfp revealed that U1:21D is the major and ubiquitously expressed copy, and the other four copies have specificities in developmental stages and tissues. Mutant strains that each have a precisely deleted copy of U1-gene exhibited various extents of defects in fly morphology or mobility, especially deletion of U1:82Eb. Interestingly, splicing was changed at limited levels in the deletion strains, while large amounts of differentially-expressed genes and alternative polyadenylation events were identified, showing preferences in the down-regulation of genes with 1-2 introns and selection of proximal sites for 3'-end polyadenylation. In vitro assays suggested that Drosophila U1 variants pulled down fewer SmD2 proteins compared to the canonical U1. This study demonstrates that all five U1-genes in Drosophila have physiological functions in development and play regulatory roles in transcription and 3'-end formation.
| S-EPMC10645366 | biostudies-literature
Project description:Full-length transcription in the majority of human genes depends on U1 snRNP (U1) to co-transcriptionally suppress transcription-terminating premature 3’-end cleavage and polyadenylation (PCPA) from cryptic polyadenylation signals (PASs) in introns. However, the mechanism of this U1 activity, termed telescripting, is unknown. Here, we captured a complex, comprising U1 and CPA factors (U1–CPAFs), that binds intronic PASs and suppresses PCPA. U1–CPAFs are distinct from U1-spliceosomal complexes; they include CPA’s three main subunits, CFIm, CPSF, and CstF, lack essential splicing factors, and associate with transcription elongation and mRNA export complexes. Telescripting requires U1:pre-mRNA base-pairing, which can be disrupted by U1 antisense oligonucleotide (U1 AMO), triggering PCPA. U1 AMO remodels U1–CPAFs, revealing changes, including recruitment of CPA-stimulating factors, that explain U1–CPAFs’ switch from repressive to activated states. Our findings outline U1 telescripting mechanism and demonstrate U1’s unique role as central-regulator of pre-mRNA processing and transcription.
2019-07-31 | GSE135140 | GEO
Project description:The goal of the microarray experiment was to do a head-to-head comparison of the U1 Adaptor technology with siRNA in terms of specificity at the genome-wide level. U1 Adaptors represent a novel gene silencing method that employs a mechanism of action distinct from antisense and RNA interference (RNAi). The U1 Adaptor is a bifunctional oligonucleotide having a âTarget Domainâ that is complementary to a site in the target gene's terminal exon and a âU1 Domainâ that binds to the U1 small nuclear RNA (snRNA) component of the U1 small nuclear ribonucleoprotein (U1 snRNP) splicing factor. Tethering of U1 snRNP to the target pre-mRNA inhibits 3' end processing (i.e., polyA tail addition) leading to degradation of that RNA species within the nucleus thereby reducing mRNA levels. We demonstrate that U1 Adaptors can specifically inhibit both reporter and endogenous genes. Further, targeting the same gene either with multiple U1 Adaptors or with U1 Adaptors and small interfering RNAs (siRNAs), strongly enhances gene silencing, the latter as predicted from their distinct mechanisms of action. Such combinatorial targeting requires lower amounts of oligonucleotides to achieve potent silencing. Experiment Overall Design: For each sample total RNA was prepared from 3 independent transfections and then were pooled and analyzed by QPCR and also by microarray.
2009-02-21 | E-GEOD-14434 | biostudies-arrayexpress
Project description:To globally assess the effect of polyadenylation site (PAS) usage upon functional knockdown of U1 snRNP, we carried out PAS-seq analysis with control and U1 AMO-treated HeLa cells using the QuantSeq Rev 3' mRNA sequencing library prep kit (Cat. 016-24).
2019-01-22 | GSE125397 | GEO
Project description:The goal of the microarray experiment was to do a head-to-head comparison of the U1 Adaptor technology with siRNA in terms of specificity at the genome-wide level. U1 Adaptors represent a novel gene silencing method that employs a mechanism of action distinct from antisense and RNA interference (RNAi). The U1 Adaptor is a bifunctional oligonucleotide having a “Target Domain” that is complementary to a site in the target gene's terminal exon and a “U1 Domain” that binds to the U1 small nuclear RNA (snRNA) component of the U1 small nuclear ribonucleoprotein (U1 snRNP) splicing factor. Tethering of U1 snRNP to the target pre-mRNA inhibits 3' end processing (i.e., polyA tail addition) leading to degradation of that RNA species within the nucleus thereby reducing mRNA levels. We demonstrate that U1 Adaptors can specifically inhibit both reporter and endogenous genes. Further, targeting the same gene either with multiple U1 Adaptors or with U1 Adaptors and small interfering RNAs (siRNAs), strongly enhances gene silencing, the latter as predicted from their distinct mechanisms of action. Such combinatorial targeting requires lower amounts of oligonucleotides to achieve potent silencing.
2009-02-08 | GSE14434 | GEO
Project description:U1 snRNA is the small nuclear RNA that services as the backbone of U1 snRNP. Removing intron from pre-mRNA to produce mature mRNA is the core function of the U1 snRNA. As one of the most abundant small noncoding RNA in human cells – estimated to be in the region of 1x10^6 copies per human cell (Hela) – U1 snRNA level is much more abundant than the other snRNAs. However, the potential role of the different amounts of the snRNAs is still unknown. To study the function of U1 snRNA in human neurons, we used lentivirus vector to overexpression U1 snRNA. We analyzed the gene expression change and identified target genes of U1 snRNA overexpression. We uncovered a novel role of U1 snRNA in regulating gene expression in human neurons.
2020-01-01 | GSE124951 | GEO
Project description:To reveal the effect of U1 snRNA mutation, we performed exogenous expression analysis of U1 snRNA mutation. The pLKO.1-puro U6 sgRNA BfuAI stuffer lentiviral vector was modified by removing the internal U6 promoter. It was replaced by the U1 locus, including 393 bases of internal native U1 promoter, the U1 sequence, and 39 bases of 3’-flanking region. The r.3A>G mutation was introduced by site-directed mutagenesis. HEK-293T cells were transfected using Lipofectamine Plus with either pLKO.1-U1wt or pLKO.1-U1r.3a>g in duplicate. Messenger RNA library construction was performed based on oligo dT-based mRNA isolation using NEBNext® Poly(A) mRNA Magnetic Isolation Module. RNA Sequence was performed on NextSeq 550 using 100-bp paired-end mode.
2019-10-09 | GSE128005 | GEO
Project description:The Arabidopsis U1 snRNP regulates mRNA 3’-end processing
| PRJEB65251 | ENA
Project description:Removal of introns during pre-mRNA splicing, which is central to gene expression, initiates by base pairing of U1 snRNA with a 5' splice site (5'SS). In mammals, many introns contain weak 5'SSs that are not efficiently recognized by the canonical U1 snRNP, suggesting alternative mechanisms exist. Here, we develop a cross-linking immunoprecipitation coupled to a high-throughput sequencing method, BCLIP-seq, to identify NRDE2 (Nuclear RNAi defective-2) and CCDC174 (Coiled-Coil Domain-Containing 174) as novel RNA-binding proteins in mouse ES cells that associate with U1 snRNA and unspliced 5'SSs. Both proteins bind directly to U1 snRNA independently of canonical U1 snRNP specific proteins, and they are required for the selection and effective processing of weak 5'SSs. Our results reveal that mammalian cells use non-canonical splicing factors bound directly to U1 snRNA to effectively select suboptimal 5'SS sequences in hundreds of genes, promoting proper splice site choice and accurate pre-mRNA splicing.
2023-09-07 | PXD029392 | Pride