scholarly journals FUS ALS-causative mutations impair FUS autoregulation and splicing factor networks through intron retention

2020 ◽  
Vol 48 (12) ◽  
pp. 6889-6905 ◽  
Author(s):  
Jack Humphrey ◽  
Nicol Birsa ◽  
Carmelo Milioto ◽  
Martha McLaughlin ◽  
Agnieszka M Ule ◽  
...  
Keyword(s):  
Rna Processing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intron Retention ◽  
Mrna Splicing ◽  
Loss Of Function ◽  
Induced Changes ◽  
The Impact ◽  
High Depth ◽  
Lateral Sclerosis

Abstract Mutations in the RNA-binding protein FUS cause amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease. FUS plays a role in numerous aspects of RNA metabolism, including mRNA splicing. However, the impact of ALS-causative mutations on splicing has not been fully characterized, as most disease models have been based on overexpressing mutant FUS, which will alter RNA processing due to FUS autoregulation. We and others have recently created knockin models that overcome the overexpression problem, and have generated high depth RNA-sequencing on FUS mutants in parallel to FUS knockout, allowing us to compare mutation-induced changes to genuine loss of function. We find that FUS-ALS mutations induce a widespread loss of function on expression and splicing. Specifically, we find that mutant FUS directly alters intron retention levels in RNA-binding proteins. Moreover, we identify an intron retention event in FUS itself that is associated with its autoregulation. Altered FUS levels have been linked to disease, and we show here that this novel autoregulation mechanism is altered by FUS mutations. Crucially, we also observe this phenomenon in other genetic forms of ALS, including those caused by TDP-43, VCP and SOD1 mutations, supporting the concept that multiple ALS genes interact in a regulatory network.

scholarly journals FUS ALS-causative mutations impact FUS autoregulation and the processing of RNA-binding proteins through intron retention

2019 ◽  
Author(s):  
Jack Humphrey ◽  
Nicol Birsa ◽  
Carmelo Milioto ◽  
David Robaldo ◽  
Andrea B Eberle ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intron Retention ◽  
Loss Of Function ◽  
Sequencing Data ◽  
Induced Changes ◽  
The Impact ◽  
Progressive Weakness

AbstractMutations in the RNA-binding protein FUS cause amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease in which the loss of motor neurons induces progressive weakness and death from respiratory failure, typically only 3-5 years after onset. FUS plays a role in numerous aspects of RNA metabolism, including mRNA splicing. However, the impact of ALS-causative mutations on splicing has not been fully characterised, as most disease models have been based on FUS overexpression, which in itself alters its RNA processing functions. To overcome this, we and others have recently created knock-in models, and have generated high depth RNA-sequencing data on FUS mutants in parallel to FUS knockout. We combined three independent datasets with a joint modelling approach, allowing us to compare the mutation-induced changes to genuine loss of function. We find that FUS ALS-mutations induce a widespread loss of function on expression and splicing, with a preferential effect on RNA binding proteins. Mutant FUS induces intron retention changes through RNA binding, and we identify an intron retention event in FUS itself that is associated with its autoregulation. Altered FUS regulation has been linked to disease, and intriguingly, we find FUS autoregulation to be altered not only by FUS mutations, but also in other genetic forms of ALS, including those caused by TDP-43, VCP and SOD1 mutations, supporting the concept that multiple ALS genes interact in a regulatory network.

scholarly journals RNA-Binding Proteins in Amyotrophic Lateral Sclerosis and Neurodegeneration

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Scott E. Ugras ◽  
James Shorter
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Disease ◽  
Rna Processing ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Future Studies ◽  
Inclusion Formation ◽  
Als Patients ◽  
Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is an adult onset neurodegenerative disease, which is universally fatal. While the causes of this devastating disease are poorly understood, recent advances have implicated RNA-binding proteins (RBPs) that contain predicted prion domains as a major culprit. Specifically, mutations in the RBPs TDP-43 and FUS can cause ALS. Cytoplasmic mislocalization and inclusion formation are common pathological features of TDP-43 and FUS proteinopathies. Though these RBPs share striking pathological and structural similarities, considerable evidence suggests that the ALS-linked mutations in TDP-43 and FUS can cause disease by disparate mechanisms. In a recent study, Couthouis et al. screened for protein candidates that were also involved in RNA processing, contained a predicted prion domain, shared other phenotypic similarities with TDP-43 and FUS, and identified TAF15 as a putative ALS gene. Subsequent sequencing of ALS patients successfully identified ALS-linked mutations in TAF15 that were largely absent in control populations. This study underscores the important role that perturbations in RNA metabolism might play in neurodegeneration, and it raises the possibility that future studies will identify other RBPs with critical roles in neurodegenerative disease.

scholarly journals Splicing Control in Normal and Aberrant Erythropoiesis

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. SCI-47-SCI-47
Author(s):  
Esther Obeng
Keyword(s):  
Gene Expression ◽  
Rna Processing ◽  
Iron Transport ◽  
Rna Binding ◽  
Intron Retention ◽  
Point Mutations ◽  
Cytoskeletal Proteins ◽  
Mrna Splicing ◽  
Splice Sites ◽  
Erythroid Maturation

Abstract Alternative splicing is employed by all eukaryotic cells to increase proteome diversity and to regulate gene expression. RNA sequencing analysis of purified populations of erythroblasts at different stages of maturation has led to the identification of a dynamic alternative splicing program that directly modulates the protein isoform expression of cytoskeletal proteins and genes involved in RNA processing, heme biosynthesis, and iron transport. Regulated interactions of multiple RNA-binding proteins and cis-regulatory sequences located within exons or their flanking introns promote or inhibit functional spliceosome assembly at splice junctions, leading to altered exon inclusion or intron retention. Exon skipping regulates tissue and stage specific isoform expression of red cell membrane cytoskeletal proteins including EPB41, ankyrin, and band 3. Intron retention can lead to a frame shift during translation and introduction of a premature termination codon (PTC), that marks the transcript for degradation via the nonsense mediated decay pathway (NMD) upon export from the nucleus into the cytoplasm. Intron retention leading to posttranscriptional regulation of gene expression during terminal erythroid maturation has been identified in genes involved in RNA processing and iron transport including SF3B1, SNRNP70, SLC25A37 and SLC25A28. Mutations that alter mRNA splice sites or introduce PTCs lead to a variety of congenital anemias including beta thalassemia, hereditary pyropoikilocytosis, hereditary elliptocytosis, and hereditary spherocytosis. Aberrant mRNA splicing has subsequently been shown to lead to acquired anemias in subsets of patients with myelodysplastic syndromes (MDS). Somatic missense mutations in components of the spliceosome are the most common category of mutations in MDS. These point mutations lead to changes in the RNA binding specificity of the involved proteins and aberrant splicing of a subset of transcripts. Mutant SF3B1, the most commonly mutated splicing factor in MDS, has been shown to cause aberrant pre-mRNA splicing and an increase in transcripts predicted to undergo NMD due to use of upstream, cryptic 3' splice sites. Our group and others evaluating the strong genotype-phenotype association between SF3B1 point mutations and subtypes of MDS with ring sideroblasts have shown that the expression of the mitochondrial iron transporter, ABCB7, is decreased in samples from SF3B1-mutant MDS patients due to cryptic 3' splice site selection and introduction of a PTC between exons 8 and 9. The identification and functional validation of additional aberrantly spliced mutant-SF3B1 target genes is ongoing, with the goal of understanding how point mutations in a core component of the mRNA splicing machinery can lead to such specific effects on erythroid maturation. Disclosures No relevant conflicts of interest to declare.

scholarly journals RES complex is associated with intron definition and required for zebrafish early embryogenesis

2017 ◽  
Author(s):  
Juan P. Fernandez ◽  
Miguel A. Moreno-Mateos ◽  
Andre Gohr ◽  
Shun Hang Chan ◽  
Manuel Irimia ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Splicing ◽  
Vertebrate Development ◽  
Loss Of Function ◽  
Recognition Elements ◽  
Splicing Patterns ◽  
The Brain ◽  
Intron Definition

AbstractPre-mRNA splicing is a critical step of gene expression in eukaryotes. Transcriptome-wide splicing patterns are complex and primarily regulated by a diverse set of recognition elements and associated RNA-binding proteins. The retention and splicing (RES) complex is formed by three different proteins (Bud13p, Pml1p and Snu17p) and is involved in splicing in yeast. However, the importance of the RES complex for vertebrate splicing, the intronic features associated with its activity, and its role in development are unknown. In this study, we have generated loss-of-function mutants for the three components of the RES complex in zebrafish and showed that they are required during early development. The mutants showed a marked neural phenotype with increased cell death in the brain and a decrease in differentiated neurons. Transcriptomic analysis of bud13, snip1 (pml1) and rbmx2 (snu17) mutants revealed a global defect in intron splicing, with strong mis-splicing of a subset of introns. We found these RES-dependent introns were short, rich in GC and flanked by GC depleted exons, all of which are features associated with intron definition. Using these features we developed a predictive model that classifies RES dependent introns. Altogether, our study uncovers the essential role of the RES complex during vertebrate development and provides new insights into its function during splicing.

scholarly journals Genetic enhancement of RNA-processing defects by a dominant mutation in B52, the Drosophila gene for an SR protein splicing factor.

1995 ◽  
Vol 15 (11) ◽  
pp. 6273-6282 ◽  
Author(s):  
X Peng ◽  
S M Mount
Keyword(s):  
Splice Site ◽  
Rna Processing ◽  
Rna Binding ◽  
Critical Role ◽  
Mrna Splicing ◽  
Genetic Enhancement ◽  
X Rays ◽  
Loss Of Function ◽  
Sr Protein ◽  
Processing Defects

SR proteins are essential for pre-mRNA splicing in vitro, act early in the splicing pathway, and can influence alternative splice site choice. Here we describe the isolation of both dominant and loss-of-function alleles of B52, the gene for a Drosophila SR protein. The allele B52ED was identified as a dominant second-site enhancer of white-apricot (wa), a retrotransposon insertion in the second intron of the eye pigmentation gene white with a complex RNA-processing defect. B52ED also exaggerates the mutant phenotype of a distinct white allele carrying a 5' splice site mutation (wDR18), and alters the pattern of sex-specific splicing at doublesex under sensitized conditions, so that the male-specific splice is favored. In addition to being a dominant enhancer of these RNA-processing defects, B52ED is a recessive lethal allele that fails to complement other lethal alleles of B52. Comparison of B52ED with the B52+ allele from which it was derived revealed a single change in a conserved amino acid in the beta 4 strand of the first RNA-binding domain of B52, which suggests that altered RNA binding is responsible for the dominant phenotype. Reversion of the B52ED dominant allele with X rays led to the isolation of a B52 null allele. Together, these results indicate a critical role for the SR protein B52 in pre-mRNA splicing in vivo.

scholarly journals Pleiotropic requirements for human TDP-43 in the regulation of cell and organelle homeostasis

2019 ◽  
Author(s):  
Agnes Roczniak-Ferguson ◽  
Shawn M. Ferguson
Keyword(s):  
Target Genes ◽  
Rna Binding ◽  
Complete Loss ◽  
Mrna Splicing ◽  
Nuclear Pore ◽  
Loss Of Function ◽  
Nuclear Pore Protein ◽  
Morphological Defects ◽  
Lateral Sclerosis ◽  
Pore Protein

AbstractTDP-43 is an RNA-binding protein that forms cytoplasmic aggregates in multiple neurodegenerative diseases. Although the loss of normal TDP-43 functions likely contributes to disease pathogenesis, the cell biological consequences of human TDP-43 depletion are not well understood. We therefore generated human TDP-43 knockout cells and subjected them to parallel cell biological and transcriptomic analyses. These efforts yielded three important discoveries. First, complete loss of TDP-43 resulted in widespread morphological defects related to multiple organelles including: Golgi, endosomes, lysosomes, mitochondria and the nuclear envelope. Second, we identified a new role for TDP-43 in controlling mRNA splicing of Nup188 (nuclear pore protein). Third, analysis of multiple amyotrophic lateral sclerosis (ALS) causing TDP-43 mutations revealed a broad ability to support splicing of TDP-43 target genes. However, as some TDP-43 disease causing mutants failed to support the regulation of specific target transcripts, our results raise the possibility of mutation-specific loss-of-function contributions to disease pathology.

scholarly journals Pleiotropic requirements for human TDP-43 in the regulation of cell and organelle homeostasis

2019 ◽  
Vol 2 (5) ◽  
pp. e201900358 ◽  
Author(s):  
Agnes Roczniak-Ferguson ◽  
Shawn M Ferguson
Keyword(s):  
Target Genes ◽  
Rna Binding ◽  
Complete Loss ◽  
Mrna Splicing ◽  
Nuclear Pore ◽  
Loss Of Function ◽  
Nuclear Pore Protein ◽  
Morphological Defects ◽  
Lateral Sclerosis ◽  
Pore Protein

TDP-43 is an RNA-binding protein that forms cytoplasmic aggregates in multiple neurodegenerative diseases. Although the loss of normal TDP-43 functions likely contributes to disease pathogenesis, the cell biological consequences of human TDP-43 depletion are not well understood. We, therefore, generated human TDP-43knockout (KO) cells and subjected them to parallel cell biological and transcriptomic analyses. These efforts yielded three important discoveries. First, complete loss of TDP-43 resulted in widespread morphological defects related to multiple organelles, including Golgi, endosomes, lysosomes, mitochondria, and the nuclear envelope. Second, we identified a new role for TDP-43 in controlling mRNA splicing of Nup188 (nuclear pore protein). Third, analysis of multiple amyotrophic lateral sclerosis causing TDP-43 mutations revealed a broad ability to support splicing of TDP-43 target genes. However, as some TDP-43 disease-causing mutants failed to fully support the regulation of specific target transcripts, our results raise the possibility of mutation-specific loss-of-function contributions to disease pathology.

scholarly journals An aberrant cytoplasmic intron retention programme is a blueprint for ALS-related RBP mislocalization

2020 ◽  
Author(s):  
Giulia E. Tyzack ◽  
Jacob Neeves ◽  
Pierre Klein ◽  
Hamish Crerar ◽  
Oliver Ziff ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intron Retention ◽  
Gene Mutations ◽  
Specific Protein ◽  
Time Resolved ◽  
Nuclear Abundance ◽  
Health And Disease ◽  
Insight Into ◽  
Lateral Sclerosis

SUMMARYWe recently described aberrant cytoplasmic SFPQ intron-retaining transcripts (IRTs) and concurrent SFPQ protein mislocalization as a new hallmark of amyotrophic lateral sclerosis (ALS). However the generalizability and potential roles of cytoplasmic IRTs in health and disease remain unclear. Here, using time-resolved deep-sequencing of nuclear and cytoplasmic fractions of hiPSCs undergoing motor neurogenesis, we reveal that ALS-causing VCP gene mutations lead to compartment-specific aberrant accumulation of IRTs. Specifically, we identify >100 IRTs with increased cytoplasmic (but not nuclear) abundance in ALS samples. Furthermore, these aberrant cytoplasmic IRTs possess sequence-specific attributes and differential predicted binding affinity to RNA binding proteins (RBPs). Remarkably, TDP-43, SFPQ and FUS – RBPs known for nuclear-to-cytoplasmic mislocalization in ALS – avidly and specifically bind to this aberrant cytoplasmic pool of IRTs, as opposed to any individual IRT. Our data are therefore consistent with a novel role for cytoplasmic IRTs in regulating compartment-specific protein abundance. This study provides new molecular insight into potential pathomechanisms underlying ALS and highlights aberrant cytoplasmic IRTs as potential therapeutic targets.Abstract Figure

scholarly journals Molecular Network Analysis Suggests a Logical Hypothesis for the Pathological Role of C9orf72 in Amyotrophic Lateral Sclerosis/Frontotemporal Dementia

2014 ◽  
Vol 6 ◽  
pp. JCNSD.S18103 ◽  
Author(s):  
Jun-Ichi Satoh ◽  
Yoji Yamamoto ◽  
Shouta Kitano ◽  
Mika Takitani ◽  
Naohiro Asahina ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Amyotrophic Lateral Sclerosis ◽  
Frontotemporal Dementia ◽  
Motor Neurons ◽  
Rna Processing ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cytoskeletal Dynamics ◽  
Lateral Sclerosis

Background Expanded GGGGCC hexanucleotide repeats, ranging from hundreds to thousands in number, located in the noncoding region of the chromosome 9 open reading frame 72 ( C9orf72) gene represent the most common genetic abnormality for familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (abbreviated as C9ALS). Currently, three pathological mechanisms, such as haplo insufficiency of C9orf72, formation of nuclear RNA foci composed of sense and antisense repeats, and accumulation of unconventionally transcribed dipeptide-repeat (DPR) proteins, are proposed for C9ALS. However, at present, the central mechanism underlying neurodegeneration in C9ALS remains largely unknown. Methods By using three distinct pathway analysis tools of bioinformatics, we studied molecular networks involved in C9ALS pathology by focusing on C9orf72 omics datasets, such as proteome of C9orf72 repeat RNA-binding proteins, transcriptome of induced pluripotent stem cells (iPSC)-derived motor neurons of patients with C9ALS, and transcriptome of purified motor neurons of patients with C9ALS. Results We found that C9orf72 repeat RNA-binding proteins play a crucial role in the regulation of post-transcriptional RNA processing. The expression of a wide range of extracellular matrix proteins and matrix metalloproteinases was reduced in iPSC-derived motor neurons of patients with C9ALS. The regulation of RNA processing and cytoskeletal dynamics is disturbed in motor neurons of patients with C9ALS in vivo. Conclusions Bioinformatics data mining approach suggests a logical hypothesis that C9orf72 repeat expansions that deregulate post-transcriptional RNA processing disturb the homeostasis of cytoskeletal dynamics and remodeling of extracellular matrix, leading to degeneration of stress-vulnerable neurons in the brain and spinal cord of patients with C9ALS.

scholarly journals Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis

Blood ◽  
2009 ◽  
Vol 113 (14) ◽  
pp. 3363-3370 ◽  
Author(s):  
Miki L. Yamamoto ◽  
Tyson A. Clark ◽  
Sherry L. Gee ◽  
Jeong-Ah Kang ◽  
Anthony C. Schweitzer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Processing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Erythroid Differentiation ◽  
Mrna Splicing ◽  
Altered Expression ◽  
Expression Microarrays ◽  
And Function ◽  
Protein 4.1R

Abstract Differentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high-resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as 3 changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that 3 of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together, these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.

Sign in / Sign up

Export Citation Format

Share Document