scholarly journals Chromatin modifier MTA1 regulates mitotic transition and tumorigenesis by orchestrating mitotic mRNA processing

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Liu ◽  
Chunxiao Li ◽  
Jinsong Wang ◽  
Dongkui Xu ◽  
Haijuan Wang ◽  
...  

Abstract Dysregulated alternative splicing (AS) driving carcinogenetic mitosis remains poorly understood. Here, we demonstrate that cancer metastasis-associated antigen 1 (MTA1), a well-known oncogenic chromatin modifier, broadly interacts and co-expresses with RBPs across cancers, contributing to cancerous mitosis-related AS. Using developed fCLIP-seq technology, we show that MTA1 binds abundant transcripts, preferentially at splicing-responsible motifs, influencing the abundance and AS pattern of target transcripts. MTA1 regulates the mRNA level and guides the AS of a series of mitosis regulators. MTA1 deletion abrogated the dynamic AS switches of variants for ATRX and MYBL2 at mitotic stage, which are relevant to mitosis-related tumorigenesis. MTA1 dysfunction causes defective mitotic arrest, leads to aberrant chromosome segregation, and results in chromosomal instability (CIN), eventually contributing to tumorigenesis. Currently, little is known about the RNA splicing during mitosis; here, we uncover that MTA1 binds transcripts and orchestrates dynamic splicing of mitosis regulators in tumorigenesis.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Saikat Bhattacharya ◽  
Michaella J. Levy ◽  
Ning Zhang ◽  
Hua Li ◽  
Laurence Florens ◽  
...  

AbstractHeterogeneous ribonucleoproteins (hnRNPs) are RNA binding molecules that are involved in key processes such as RNA splicing and transcription. One such hnRNP protein, hnRNP L, regulates alternative splicing (AS) by binding to pre-mRNA transcripts. However, it is unclear what factors contribute to hnRNP L-regulated AS events. Using proteomic approaches, we identified several key factors that co-purify with hnRNP L. We demonstrate that one such factor, the histone methyltransferase SETD2, specifically interacts with hnRNP L in vitro and in vivo. This interaction occurs through a previously uncharacterized domain in SETD2, the SETD2-hnRNP Interaction (SHI) domain, the deletion of which, leads to a reduced H3K36me3 deposition. Functionally, SETD2 regulates a subset of hnRNP L-targeted AS events. Our findings demonstrate that SETD2, by interacting with Pol II as well as hnRNP L, can mediate the crosstalk between the transcription and the splicing machinery.


Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 953-964 ◽  
Author(s):  
D P Moore ◽  
W Y Miyazaki ◽  
J E Tomkiel ◽  
T L Orr-Weaver

Abstract We describe a Drosophila mutation, Double or nothing (Dub), that causes meiotic nondisjunction in a conditional, dominant manner. Previously isolated mutations in Drosophila specifically affect meiosis either in females or males, with the exception of the mei-S332 and ord genes which are required for proper sister-chromatid cohesion. Dub is unusual in that it causes aberrant chromosome segregation almost exclusively in meiosis I in both sexes. In Dub mutant females both nonexchange and exchange chromosomes undergo nondisjunction, but the effect of Dub on nonexchange chromosomes is more pronounced. Dub reduces recombination levels slightly. Multiple nondisjoined chromosomes frequently cosegregate to the same pole. Dub results in nondisjunction of all chromosomes in meiosis I of males, although the levels are lower than in females. When homozygous, Dub is a conditional lethal allele and exhibits phenotypes consistent with cell death.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1720
Author(s):  
Kuo-Chieh Liao ◽  
Mariano A. Garcia-Blanco

The importance of transcriptional regulation of host genes in innate immunity against viral infection has been widely recognized. More recently, post-transcriptional regulatory mechanisms have gained appreciation as an additional and important layer of regulation to fine-tune host immune responses. Here, we review the functional significance of alternative splicing in innate immune responses to viral infection. We describe how several central components of the Type I and III interferon pathways encode spliced isoforms to regulate IFN activation and function. Additionally, the functional roles of splicing factors and modulators in antiviral immunity are discussed. Lastly, we discuss how cell death pathways are regulated by alternative splicing as well as the potential role of this regulation on host immunity and viral infection. Altogether, these studies highlight the importance of RNA splicing in regulating host–virus interactions and suggest a role in downregulating antiviral innate immunity; this may be critical to prevent pathological inflammation.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wen-juan Li ◽  
Yao-hui He ◽  
Jing-jing Yang ◽  
Guo-sheng Hu ◽  
Yi-an Lin ◽  
...  

AbstractNumerous substrates have been identified for Type I and II arginine methyltransferases (PRMTs). However, the full substrate spectrum of the only type III PRMT, PRMT7, and its connection to type I and II PRMT substrates remains unknown. Here, we use mass spectrometry to reveal features of PRMT7-regulated methylation. We find that PRMT7 predominantly methylates a glycine and arginine motif; multiple PRMT7-regulated arginine methylation sites are close to phosphorylations sites; methylation sites and proximal sequences are vulnerable to cancer mutations; and methylation is enriched in proteins associated with spliceosome and RNA-related pathways. We show that PRMT4/5/7-mediated arginine methylation regulates hnRNPA1 binding to RNA and several alternative splicing events. In breast, colorectal and prostate cancer cells, PRMT4/5/7 are upregulated and associated with high levels of hnRNPA1 arginine methylation and aberrant alternative splicing. Pharmacological inhibition of PRMT4/5/7 suppresses cancer cell growth and their co-inhibition shows synergistic effects, suggesting them as targets for cancer therapy.


2006 ◽  
Vol 26 (1) ◽  
pp. 362-370 ◽  
Author(s):  
Chonghui Cheng ◽  
Phillip A. Sharp

ABSTRACT The multiple isoforms of the transmembrane glycoprotein CD44 are produced by alternative RNA splicing. Expression of CD44 isoforms containing variable 5 exon (v5) correlates with enhanced malignancy and invasiveness of some tumors. Here we demonstrate that SRm160, a splicing coactivator, regulates CD44 alternative splicing in a Ras-dependent manner. Overexpression of SRm160 stimulates inclusion of CD44 v5 when Ras is activated. Conversely, small interfering RNA (siRNA)-mediated silencing of SRm160 significantly reduces v5 inclusion. Immunoprecipitation shows association of SRm160 with Sam68, a protein that also stimulates v5 inclusion in a Ras-dependent manner, suggesting that these two proteins interact to regulate CD44 splicing. Importantly, siRNA-mediated depletion of CD44 v5 decreases tumor cell invasion. Reduction of SRm160 by siRNA transfection downregulates the endogenous levels of CD44 isoforms, including v5, and correlates with a decrease in tumor cell invasiveness.


1989 ◽  
Vol 9 (10) ◽  
pp. 4364-4371
Author(s):  
C Delsert ◽  
N Morin ◽  
D F Klessig

Expression of the L1 region of adenovirus is temporally regulated by alternative splicing to yield two major RNAs encoding the 52- to 55-kilodalton (52-55K) and IIIa polypeptides. The distal acceptor site (IIIa) is utilized only during the late phase of infection, whereas the proximal site (52-55K) is used at both early and late times. Several parameters that might affect this alternative splicing were tested by using expression vectors carrying the L1 region or mutated versions of it. In the absence of a virus-encoded or -induced factor(s), only the 52-55K acceptor was used. Decreasing the distance between the donor and the IIIa acceptor had no effect. Removal of the 52-55K acceptor induced IIIa splicing slightly, implying competition between the two acceptors. Fusion of the IIIa exon to the 52-55K intron greatly enhanced splicing of the IIIa junction, suggesting that the IIIa exon does not contain sequences that inhibit splicing. Thus, the lack of splicing to the IIIa acceptor in the absence of a virus-encoded or -induced factor(s) is probably due to the absence of a favorable sequence and/or the presence of a negative element 5' of the IIIa splice junction, or both. The presence of several adenovirus gene products, including VA RNAs, the E2A DNA-binding protein, and the products of E1A and E1B genes, did not facilitate use of the IIIa acceptor. In contrast, the simian virus 40 early proteins, probably large T antigen, induced IIIa splicing. This result, together with those of earlier studies, suggest that T antigen plays a role in modulation of alternative RNA splicing.


2017 ◽  
Vol 114 (38) ◽  
pp. 10238-10243 ◽  
Author(s):  
Xiaorong Zhang ◽  
G. Paul H. van Heusden ◽  
Paul J. J. Hooykaas

The bacteriumAgrobacterium tumefacienscauses crown gall tumor formation in plants. During infection the bacteria translocate an oncogenic piece of DNA (transferred DNA, T-DNA) into plant cells at the infection site. A number of virulence proteins are cotransported into host cells concomitantly with the T-DNA to effectuate transformation. Using yeast as a model host, we find that one of these proteins, VirD5, localizes to the centromeres/kinetochores in the nucleus of the host cells by its interaction with the conserved protein Spt4. VirD5 promotes chromosomal instability as seen by the high-frequency loss of a minichromosome in yeast. By using both yeast and plant cells with a chromosome that was specifically marked by alacOrepeat, chromosome segregation errors and the appearance of aneuploid cells due to the presence of VirD5 could be visualized in vivo. Thus, VirD5 is a prokaryotic virulence protein that interferes with mitosis.


2017 ◽  
Author(s):  
Adriana Buskin ◽  
Lili Zhu ◽  
Valeria Chichagova ◽  
Basudha Basu ◽  
Sina Mozaffari-Jovin ◽  
...  

SummaryMutations in pre-mRNA processing factors (PRPFs) cause 40% of autosomal dominant retinitis pigmentosa (RP), but it is unclear why mutations in ubiquitously expressed PRPFs cause retinal disease. To understand the molecular basis of this phenotype, we have generated RP type 11 (PRPF31-mutated) patient-specific retinal organoids and retinal pigment epithelium (RPE) from induced pluripotent stem cells (iPSC). Impaired alternative splicing of genes encoding pre-mRNA splicing proteins occurred in patient-specific retinal cells and Prpf31+/− mouse retinae, but not fibroblasts and iPSCs, providing mechanistic insights into retinal-specific phenotypes of PRPFs. RPE was the most affected, characterised by loss of apical-basal polarity, reduced trans-epithelial resistance, phagocytic capacity, microvilli, and cilia length and incidence. Disrupted cilia morphology was observed in patient-derived-photoreceptors that displayed progressive features associated with degeneration and cell stress. In situ gene-editing of a pathogenic mutation rescued key structural and functional phenotypes in RPE and photoreceptors, providing proof-of-concept for future therapeutic strategies.eTOCPRPF31 is a ubiquitously expressed pre-mRNA processing factor that when mutated causes autosomal dominant RP. Using a patient-specific iPSC approach, Buskin and Zhu et al. show that retinal-specific defects result from altered splicing of genes involved in the splicing process itself, leading to impaired splicing, loss of RPE polarity and diminished phagocytic ability as well as reduced cilia incidence and length in both photoreceptors and RPE.HighlightsSuccessful generation of iPSC-derived RPE and photoreceptors from four RP type 11 patientsRPE cells express the mutant PRPF31 protein and show the lowest expression of wildtype proteinPRPF31 mutations result in altered splicing of genes involved in pre-mRNA splicing in RPE and retinal organoidsPrpf31 haploinsufficiency results in altered splicing of genes involved in pre-mRNA splicing in mouse retinaRPE cells display loss of polarity, reduced barrier function and phagocytosisPhotoreceptors display shorter and fewer cilia and degenerative featuresRPE cells display most abnormalities suggesting they might be the primary site of pathogenesisIn situ gene editing corrects the mutation and rescues key phenotypes


2020 ◽  
Author(s):  
Shani T. Gal-Oz ◽  
Nimrod Haiat ◽  
Dana Eliyahu ◽  
Guy Shani ◽  
Tal Shay

AbstractAlternative RNA splicing results in multiple transcripts of the same gene, possibly encoding for different protein isoforms with different protein domains and functionalities. Whereas it is possible to manually determine the effect of a specific alternative splicing event on the domain composition of a particular encoded protein, the process requires the tedious integration of several data sources; it is therefore error prone and its implementation is not feasible for genome-wide characterization of domains affected by differential splicing. To fulfill the need for an automated solution, we developed the Domain Change Presenter (DoChaP), a web server for the visualization of the exon–domain association. DoChaP visualizes all transcripts of a given gene, the domains of the proteins that they encode, and the exons encoding each domain. The visualization enables a comparison between the transcripts and between the protein isoforms they encode for. The organization and visual presentation of the information makes the structural effect of each alternative splicing event on the protein structure easily identified. To enable a study of the conservation of the exon structure, alternative splicing, and the effect of alternative splicing on protein domains, DoChaP also facilitates an inter-species comparison of domain–exon associations. DoChaP thus provides a unique and easy-to-use visualization of the exon–domain association and its conservation between transcripts and orthologous genes and will facilitate the study of the functional effects of alternative splicing in health and disease.


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