Essential requirement for polypyrimidine tract binding proteins 1 and 3 in the maturation and maintenance of mature B cells in mice
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PROVIDER: PRJNA713849 | ENA |
REPOSITORIES: ENA
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Project description:The maturation of immature B cells and the survival of mature B cells is stringently controlled to maintain a diverse repertoire of antibody specificities while avoiding self-reactivity. At the molecular level this is regulated by signalling from membrane immunoglobulin and the BAFF-receptor which sustain a pro-survival programme of gene expression. Whether and how posttranscriptional mechanisms contribute to B cell maturation and survival remains poorly understood. Here we show that the polypyrimidine tract binding proteins (PTBP) PTBP1 and PTBP3 bind to a large and overlapping set of transcripts in B cells. Both PTBP1 and PTBP3 bind to introns and exons where they are predicted to regulate alternative splicing. Moreover, they also show high density of binding in the 3’ untranslated regions suggesting they influence the transcriptome in diverse ways. We show that PTBP1 and PTBP3 are required in B cells beyond the immature cell stage to sustain transitional B cells and the B1, marginal zone and follicular B cell lineages. Therefore, PTBP1 and PTBP3 promote the survival of quiescent B cells by regulating gene expression at the post-transcriptional level.
2021-07-05 | GSE168769 | GEO
Project description:During B cell development, recombination of immunoglobulin loci is tightly coordinated with the cell cycle to avoid unwanted rearrangements of other genomic locations. Several factors have been identified that suppress proliferation in late-pre-B cells to allow light chain recombination. By comparison, our knowledge of factors limiting proliferation during heavy chain recombination at the pro-B cell stage is very limited. Here we identify an essential role for the RNA-binding protein Polypyrimidine Tract Binding Protein 1 (PTBP1) in B cell development. Absence of PTBP1 and the paralog PTBP2 results in a complete block in development at the pro-B cell stage. PTBP1 promotes the fidelity of the transcriptome in pro-B cells. In particular, PTBP1 controls a cell cycle mRNA regulon, suppresses entry into S-phase and promotes progression into mitosis. Our results highlight the importance of S-phase entry suppression and post-transcriptional gene expression control by PTBP1 in pro-B cells for proper B cell development.
2020-02-21 | GSE136882 | GEO
Project description:Diverse elements within the 5’ untranslated region of an mRNA can influence the translation efficiency at the main AUG codon. We previously identified a core picornaviral like Y16X11-AUG motif with 16-nt polypyrimidine CU-tract separated by an 11-nt spacer sequence from the 13th AUG codon recognized as the preferred initiation site within the Triticum mosaic virus (TriMV) internal ribosome entry site (IRES) element. The motif is proposed to function as an internal ribosomal landing site at the designated start codon. Here we exposed the cooperative role of multiple CU-rich segments flanking the TriMV YX-AUG motif to drive internal initiation of translation at the preferred start site. We propose that these auxiliary domains may enhance the ribosome capacity at proximity of the correct initiation site. These polypyrimidine tracts can be modulated with a cryptic AUG and in a position-dependent manner to replace the native YX-AUG motif and to reprogram translation to the upstream sites, and thus uncovering a new layer of control of the selection of the initiation site. In line with these observations, mass spec analysis of proteins directly interacting with translationally impaired TriMV IRES mutants that bear these motifs indicated an enrichment in 40S and 60S ribosomal related proteins, revealing a new function of polypyrimidine tracts to regulate IRES-driven translation. Accessibility of these RNA regions for in trans interaction was validated by SHAPE analysis of the entire TriMV leader sequence and supported by the ability of anti-sense oligonucleotides designed to block the CU-tracts accessibility to impair IRES activity. This is the first evidence that defines the core modular domains required for start codon selection in a complex, multi-AUG viral 5’UTR for translation in plants.
2022-05-04 | PXD031443 | Pride
Project description:RNA binding proteins play an important role in regulating alternative pre-mRNA splicing and in turn cellular gene expression. Polypyrimidine tract binding proteins, PTBP1 and PTBP2, are paralogous RNA binding proteins that play a critical role in the process of neuronal differentiation and maturation; changes in the concentration of PTBP proteins during neuronal development direct splicing changes in many transcripts that code for proteins critical for neuronal differentiation. How the two related proteins regulate different sets of neuronal exons is unclear. The distinct splicing activities of PTBP1 and PTBP2 can be recapitulated in an in vitro splicing system with the differentially regulated N1 exon of the c-src pre-mRNA. Here, we conducted experiments under these in vitro splicing conditions to identify PTBP1 and PTBP2 interacting partner proteins.
2022-01-20 | PXD029899 | Pride
Project description:Polypyrimidine tract binding proteins are essential for B cell development
| PRJNA563911 | ENA
Project description:The Drosophila polypyrimidine tract-binding protein (dmPTB or hephaestus) plays an important role during spermatogenesis. The heph2 mutation in this gene results in a specific defect in spermatogenesis, causing aberrant spermatid individualization and male sterility. However, the array of molecular defects in the mutant remains uncharacterized. This study provides the first comprehensive list of genes misregulated in vivo in the heph2 mutant in Drosophila and offers insight into the role of dmPTB during spermatogenesis.
2017-02-09 | GSE77706 | GEO
Project description:We show that the RNA-binding protein Polypyrimidine Tract Binding Protein 1 (PTBP1) is dispensable for the development of naïve mouse CD8 T cells, but is necessary for the optimal expansion and production of effector molecules by antigen-specific CD8 T cells in vivo. PTBP1 has an essential role in regulating the early events following activation of the naïve CD8 T cell leading to IL-2 and TNF production. It is also required to protect activated CD8 T cells from apoptosis. PTBP1 controls alternative splicing of over 400 genes in naïve CD8 T cells in addition to regulating the abundance of ~200 mRNAs. PTBP1 is required for the nuclear accumulation of c-Fos, NFATc2 and NFATc3, but not NFATc1. This selective effect on NFAT proteins correlates with PTBP1-promoted expression of the shorter Ab1 isoform and exon 13 skipped Ab2 isoform of the catalytic A-sububit of calcineurin phosphatse. These findings reveal a crucial role for PTBP1 in regulating CD8 T cell activation.
2021-12-09 | GSE190512 | GEO
Project description:Alternative splicing (AS) generates transcript variants by the definition of different exonic and intronic regions and causes a massive expansion of transcriptome diversity. Changes in AS patterns have been found to be linked to manifold biological processes, yet fundamental aspects such as the regulation of AS and the functional implications of altered AS programs largely remain to be addressed. In this work, widespread AS regulation by Arabidopsis Polypyrimidine tract-binding protein homologues (AtPTBs) was revealed. In total 452 AS events derived from 308 distinct genes were found to be responsive to the levels of the splicing factors AtPTB1 and AtPTB2, which predominantly triggered splicing of regulated introns, inclusion of cassette exons, and usage of upstream 5' splice sites. In contrast, alternative 3' splice site events were strongly underrepresented among the AtPTB1/2 targets and no major AS regulatory function of the distantly related AtPTB3 was found. Dependent on their position within the mRNA, AtPTB-regulated events can both modify the untranslated regions and give rise to alternative protein products. Gene ontology analysis revealed a connection of AtPTB-mediated AS control with diverse biological processes, and the functional implications of selected AS events were further elucidated in the context of seed germination and flowering time control. Specifically, AtPTB misexpression changes AS of the PHYTOCHROME INTERACTING FACTOR 6 (PIF6) pre-mRNA, coinciding with altered rates of abscisic acid-dependent seed germination. Furthermore, AS patterns as well as the expression of key flowering regulators were massively changed in an AtPTB1/2 level-dependent manner. In conclusion, our work has revealed widespread AS regulatory functions of the AtPTB splicing factors with important functional implications in various fundamental processes of Arabidopsis development. Analysis of alternative splicing patterns in plants with increased and decreased levels of the 3 Arabidopsis Polypyrimidine-tract binding protein homologues in comparison to wild type samples, determined in duplicates
2012-10-22 | E-GEOD-41433 | biostudies-arrayexpress
Project description:Requirement for NF-kB in maintenance of molecular and behavioral circadian rhythms in mice.
| PRJNA482318 | ENA
Project description:Purpose : Splicing factors regulate splice site choices in pre-mRNA and determine final exon set in mRNA. To understand mechanisms of splicing regulation, it is important to identify and characterize exon targets of splicing factors. Recently, development of RNA-seq technology enables researchers to investigate exon splicing profiles as well as gene expression profiles in transcriptome-wide. The goal of this study is to investigate transcriptome changes by splicing factors, Polypyrimidine Tract Binding proteins (PTB). In this study, we analyzed exon and gene expression changes followed by Ptbp1 knock down. Methods : The knockdown experiment was performed in mouse neuroblastoma (N2A) cells. Total RNA was collected from cells and further treated with DNase I to avoid DNA contamination. RNA-seq libraries were constructed in a strand specific way using dUTP and Uracil-Specific Excision Reagent enzyme. The libraries were subjected to 100bp paired-end sequencing (Illumina HiSeq2000 platform). Poly(A)-mRNA and exon profiles of N2A mouse blastoma cells in two samples: shRNA transfection control, single knock down of ptbp1. RNA-seq libraries were generated in strand specific way using dUTP and USER enzyme and sequenced using Illumina HiSeq2000.
2013-12-01 | E-GEOD-45119 | biostudies-arrayexpress