Unfolding the Role of Splicing Factors and RNA Debranching in AID Mediated Antibody Diversification

2020 ◽  
pp. 1-18
Author(s):  
Ankit Jaiswal ◽  
Amit Kumar Singh ◽  
Anubhav Tamrakar ◽  
Prashant Kodgire
Keyword(s):  
Splicing Factors ◽  
Antibody Diversification

scholarly journals Delta-secretase (AEP) mediates tau-splicing imbalance and accelerates cognitive decline in tauopathies

2018 ◽  
Vol 215 (12) ◽  
pp. 3038-3056 ◽  
Author(s):  
Zhi-Hao Wang ◽  
Pai Liu ◽  
Xia Liu ◽  
Shan Ping Yu ◽  
Jian-Zhi Wang ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
Kinase Activity ◽  
Nuclear Translocation ◽  
Memory Deficits ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Synaptic Functions ◽  
Tau Isoforms ◽  
Exon 10

SRPK2 is abnormally activated in tauopathies including Alzheimer’s disease (AD). SRPK2 is known to play an important role in pre–mRNA splicing by phosphorylating SR-splicing factors. Dysregulation of tau exon 10 pre–mRNA splicing causes pathological imbalances in 3R- and 4R-tau, leading to neurodegeneration; however, the role of SRPK2 in these processes remains unclear. Here we show that delta-secretase (also known as asparagine endopeptidase; AEP), which is activated in AD, cleaves SRPK2 and increases its nuclear translocation as well as kinase activity, augmenting exon 10 inclusion. Conversely, AEP-uncleavable SRPK2 N342A mutant increases exon 10 exclusion. Lentiviral expression of truncated SRPK2 increases 4R-tau isoforms and accelerates cognitive decline in htau mice. Uncleavable SRPK2 N342A expression improves synaptic functions and prevents spatial memory deficits in tau intronic mutant FTDP-17 transgenic mice. Hence, AEP mediates tau-splicing imbalance in tauopathies via cleaving SRPK2.

The role of splicing factors in retinitis pigmentosa: links to cilia

2021 ◽  
Author(s):  
Dale W. Maxwell ◽  
Raymond T. O'Keefe ◽  
Sudipto Roy ◽  
Kathryn E. Hentges
Keyword(s):  
Retinitis Pigmentosa ◽  
Primary Cilium ◽  
Photoreceptor Cells ◽  
Genetic Mutations ◽  
Splicing Factors ◽  
Sequence Variants ◽  
Biological Functions ◽  
Progressive Degeneration

Cilia are critical to numerous biological functions, both in development and everyday homeostatic processes. Diseases arising from genetic mutations that cause cilia dysfunction are termed ciliopathies. Several ubiquitously expressed splicing factors have been implicated in the condition Retinitis Pigmentosa (RP), a group of diseases characterised by the progressive degeneration of the retina. In many types of RP the disease affects the modified primary cilium of the photoreceptor cells and thus, these types of RP are considered ciliopathies. Here, we discuss sequence variants found within a number of these splicing factors, the resulting phenotypes, and the mechanisms underpinning disease pathology. Additionally, we discuss recent evidence investigating why RP patients with mutations in globally expressed splicing factors present with retina-specific phenotypes.

scholarly journals Human Cancer-Associated Mutations of SF3B1 Lead to a Splicing Modification of Its Own RNA

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 652
Author(s):  
Tiffany Bergot ◽  
Eric Lippert ◽  
Nathalie Douet-Guilbert ◽  
Séverine Commet ◽  
Laurent Corcos ◽  
...  
Keyword(s):  
Amino Acids ◽  
Human Cancer ◽  
Myeloid Cell ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Small Nuclear Ribonucleoprotein ◽  
Genes Encoding ◽  
Protein Isoform ◽  
Nuclear Ribonucleoprotein

Deregulation of pre-mRNA splicing is observed in many cancers and hematological malignancies. Genes encoding splicing factors are frequently mutated in myelodysplastic syndromes, in which SF3B1 mutations are the most frequent. SF3B1 is an essential component of the U2 small nuclear ribonucleoprotein particle that interacts with branch point sequences close to the 3’ splice site during pre-mRNA splicing. SF3B1 mutations mostly lead to substitutions at restricted sites in the highly conserved HEAT domain, causing a modification of its function. We found that SF3B1 was aberrantly spliced in various neoplasms carrying an SF3B1 mutation, by exploring publicly available RNA sequencing raw data. We aimed to characterize this novel SF3B1 transcript, which is expected to encode a protein with an insertion of eight amino acids in the H3 repeat of the HEAT domain. We investigated the splicing proficiency of this SF3B1 protein isoform, in association with the most frequent mutation (K700E), through functional complementation assays in two myeloid cell lines stably expressing distinct SF3B1 variants. The yeast Schizosaccharomyces pombe was also used as an alternative model. Insertion of these eight amino acids in wild-type or mutant SF3B1 (K700E) abolished SF3B1 essential function, highlighting the crucial role of the H3 repeat in the splicing function of SF3B1.

The Role of Activation‐Induced Deaminase in Antibody Diversification and Chromosome Translocations

2007 ◽  
pp. 75-107 ◽  
Author(s):  
Almudena Ramiro ◽  
Bernardo Reina San‐Martin ◽  
Kevin McBride ◽  
Mila Jankovic ◽  
Vasco Barreto ◽  
...  
Keyword(s):  
Chromosome Translocations ◽  
Antibody Diversification ◽  
Activation Induced Deaminase

Abstract 3197: Splicing factors and the role of Navitoclax in drug-resistant ovarian cancer

2017 ◽  
Author(s):  
Helen M. Coley ◽  
Laura Lattanzio ◽  
Ornella Garrone ◽  
Marco Merlano ◽  
Daniela Vivenza ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Splicing Factors ◽  
Drug Resistant

scholarly journals Role of the Constitutive Splicing Factors U2AF65and SAP49 in Suboptimal RNA Splicing of Novel Retroviral Mutants

1998 ◽  
Vol 273 (24) ◽  
pp. 15169-15176 ◽  
Author(s):  
John Bouck ◽  
Xiang-Dong Fu ◽  
Anna Marie Skalka ◽  
Richard A. Katz
Keyword(s):  
Rna Splicing ◽  
Splicing Factors ◽  
Constitutive Splicing

scholarly journals Regulation of neuronal mRNA splicing and Tau isoform ratio by ATXN3 through deubiquitylation of splicing factors

2019 ◽  
Author(s):  
Andreia Neves-Carvalho ◽  
Sara Duarte-Silva ◽  
Joana Silva ◽  
Bruno Almeida ◽  
Sasja Heetveld ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Rna Metabolism ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Loss Of Function ◽  
Relevant Role ◽  
The Brain ◽  
Precise Role ◽  
Exon 10

ABSTRACTThe ubiquitylation/deubiquitylation balance in cells is maintained by Deubiquitylating enzymes, including ATXN3. The precise role of this protein, mutated in SCA3, remains elusive, as few substrates for its deubiquitylating activity were identified. Therefore, we characterized the ubiquitome of neuronal cells lacking ATXN3, and found altered polyubiquitylation in a large proportion of proteins involved in RNA metabolism, including splicing factors. Using transcriptomic analysis and reporter minigenes we confirmed that splicing was globally altered in these cells. Among the targets with altered splicing was SRSF7 (9G8), a key regulator of MAPT (Tau) exon 10 splicing. Loss-of-function of ATXN3 led to a deregulation of MAPT exon 10 splicing resulting in a decreased 4R/3R-Tau ratio. Similar alterations were found in the brain of a SCA3 mouse and humans, pointing to a relevant role of this mechanism in SCA3, and establishing a previously unsuspected link between two key proteins involved in different neurodegenerative disorders.

scholarly journals Genome-wide transcriptome analysis identifies alternative splicing regulatory network and key splicing factors in mouse and human psoriasis

2018 ◽  
Author(s):  
Jin Li ◽  
Peng Yu
Keyword(s):  
Alternative Splicing ◽  
Computational Analysis ◽  
Potential Role ◽  
Exon Skipping ◽  
Chronic Inflammatory Disease ◽  
Splicing Factors ◽  
The Novel ◽  
Rna Seq ◽  
Genome Wide

AbstractPsoriasis is a chronic inflammatory disease that affects the skin, nails, and joints. For understanding the mechanism of psoriasis, though, alternative splicing analysis has received relatively little attention in the field. Here, we developed and applied several computational analysis methods to study psoriasis. Using psoriasis mouse and human datasets, our differential alternative splicing analyses detected hundreds of differential alternative splicing changes. Our analysis of conservation revealed many exon-skipping events conserved between mice and humans. In addition, our splicing signature comparison analysis using the psoriasis datasets and our curated splicing factor perturbation RNA-Seq database, SFMetaDB, identified nine candidate splicing factors that may be important in regulating splicing in the psoriasis mouse model dataset. Three of the nine splicing factors were confirmed upon analyzing the human data. Our computational methods have generated predictions for the potential role of splicing in psoriasis. Future experiments on the novel candidates predicted by our computational analysis are expected to provide a better understanding of the molecular mechanism of psoriasis and to pave the way for new therapeutic treatments.

scholarly journals Colocalization of intranuclear lamin foci with RNA splicing factors

1999 ◽  
Vol 112 (24) ◽  
pp. 4651-4661 ◽  
Author(s):  
G. Jagatheesan ◽  
S. Thanumalayan ◽  
B. Muralikrishna ◽  
N. Rangaraj ◽  
A.A. Karande ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Rna Splicing ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Splicing Factors ◽  
Lamin A ◽  
Lamin B1 ◽  
Differential Reactivity ◽  
Fibrous Network

The lamins form a fibrous network underlying the inner nuclear membrane termed the nuclear lamina. In order to gain insights into the role of lamins in nuclear organization, we have characterized a monoclonal antibody (LA-2H10) raised against recombinant rat lamin A that labels nuclei in a speckled pattern in all cells of unsynchronized populations of HeLa and rat F-111 fibroblast cells, unlike the typical nuclear periphery staining by another monoclonal antibody to lamin A, LA-2B3. In immunolocalization studies the lamin A speckles or foci were found to colocalize with the RNA splicing factors SC-35 and U5-116 kD, but not with p80 coilin found in coiled bodies. Lamin B1 was also associated with these foci. These foci dispersed when cells entered mitosis and reformed during anaphase. The differential reactivity of LA-2H10 and LA-2B3 was retained after nuclei were extracted with detergents, nucleases and salt to disrupt interactions of lamins with chromatin and other nuclear proteins. Using deletion fragments of recombinant lamin A, the epitope recognized by LA-2H10 was located between amino acids 171 and 246. Our findings are consistent with a structural role for lamins in supporting nuclear compartments containing proteins involved in RNA splicing.

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