Abstract 124: Fetal-Like RNA Splicing Remodeling in Failing Heart Revealed by Total Transcriptome Analysis

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Chen Gao ◽  
Vincent Ren ◽  
Grace (Xinshu) Xiao ◽  
Jaunian Chen ◽  
Yibin Wang

The complexity of transcriptome and proteome is contributed by alternative splicing of mRNA. Altered mRNA splicing is also implicated in many human diseases including cancer. However, little knowledge is available about the scope of alternative splicing at whole genome level in heart diseases and even less about the mechanisms underlying the regulation of mRNA splicing in response to pathological injury in heart. Using a genome-wide RNA-Seq analysis, we have identified global alternative splicing changes associated with both development and pathological remodeling in mouse heart. Most significantly, the alternative RNA splicing events observed in failing heart mimicked the splicing profile in fetal hearts, suggesting a fetal like RNA splicing remodeling in failing hearts. After examining the expression profiles of splicing regulators in neonatal, normal adult, and failing adult hearts, Fox-1 was identified as one to be significantly down regulated in the failing and fetal hearts. Morpholino mediated Fox-1 knock-down in zebrafish embryos led to lethal phenotype associated with impaired cardiac development and function. This phenotype could be rescued by re-expressing both zebrafish and mouse Fox1 gene. Therefore, our established functional significance of Fox1 mediated RNA alternative splicing serves as a key molecular player in transcriptome remodeling during cardiac development and pathology.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
CHEN GAO ◽  
Vincent Ren ◽  
Jae-Hyung Lee ◽  
Xinshu (Grace) Xiao ◽  
Jau-nian Chen ◽  
...  

Background: The complexity of transcriptome and proteome is contributed by alternative splicing of mRNA. Altered mRNA splicing is also implicated in many human diseases including cancer. However, the global pattern of alternative mRNA splicing during cardiac development and diseases is unknown, and the regulatory mechanisms remain unexplored. Methods and Results: Using deep RNA-Sequencing, we have identified global alternative splicing changes associated with both cardiac development and pathological remodeling in mouse heart following pressure-overload induced heart failure. The alternative RNA splicing events observed in failing hearts mimics the profile in fetal hearts, suggesting a fetal-like RNA splicing program induced in diseased hearts. Using RNA-Seq database and real-time PCR analysis, we examined the expression profile of a large number of known alternative splicing regulators. Among them, we identified Fox1 as a significantly induced regulator during cardiac development in zebrafish, mouse and human, and down-regulated in both mouse and human failing hearts. Morpholino mediated Fox1 knockdown in zebrafish embryos led to lethal phenotype associated with reduced cardiac function and defects in chamber specificity. This phenotype could be rescued by re-expressing both zebrafish and mouse Fox1 gene, suggesting a highly conserved cardiac function of Fox1 for normal cardiac development and function in vertebrates. Conclusion: Our study provided the first comprehensive analysis of mRNA splicing regulation in heart during post-natal development and heart failure, and identified Fox1 as a key regulator for alternative RNA splicing in heart. This study expands our current understanding to the complexity of cardiac transcriptome, and reveals the functional importance of RNA-splicing in cardiac development and diseases.


2021 ◽  
Author(s):  
Shuiqiao Yuan ◽  
Shenglei Feng ◽  
Jinmei Li ◽  
Hui Wen ◽  
Kuan Liu ◽  
...  

Abstract Coordinated regulation of alternative pre-mRNA splicing is essential for germ cell development. However, the molecular mechanism underlying that control alternative mRNA expression during germ cell development remains poorly understood. Herein, we showed that hnRNPH1, an RNA-binding protein, is highly expressed in the reproductive system and localized in the chromosomes of meiotic cells but excluded from the XY body in pachytene spermatocytes and recruits the splicing regulators PTBP2 and SRSF3 and cooperatively regulates the alternative splicing of the critical genes that are required for spermatogenesis. Conditional knockout Hnrnph1 in spermatogenic cells caused many abnormal splicing events that affect genes related to meiosis and communication between germ cells and Sertoli cells, characterized by asynapsis of chromosomes and impairment of germ-Sertoli communications, ultimately leading to male sterility. We further showed that hnRNPH1 could directly bind to SPO11 and recruit the splicing regulators PTBP2 and SRSF3 to regulate the alternative splicing of the target genes cooperatively. Strikingly, Hnrnph1 germline-specific mutant female mice were also infertile, and Hnrnph1-deficient oocytes exhibited a similar defective synapsis and cell-cell junction as shown in Hnrnph1-deficient male germ cells. Collectively, our data reveal an essential role for hnRNPH1 in regulating pre-mRNA splicing during spermatogenesis and oogenesis and support a molecular model whereby hnRNPH1 governs a network of alternative splicing events in germ cells via recruiting PTBP2 and SRSF3.


2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Jianqiu Zou ◽  
Wenxia Ma ◽  
Jie Li ◽  
Rodney Littlejohn ◽  
Il-man Kim ◽  
...  

Rationale: Cardiac development is orchestrated by a number of growth factors, transcription factors and epigenetic regulators, perturbation of which can lead to congenital heart diseases and cardiomyopathies. However, the role of novel ubiquitin-like protein modifiers, such as NEDD8 (neural precursor cells expressed developmentally downregulated 8), in cardiac development is unknown. Objectives: The objective of this study was to determine the significance of NEDD8 modification (neddylation) during perinatal cardiac development. Methods and Results: Neddylated proteins and NEDD8 enzymes were highly abundant in fetal and neonatal hearts but downregulated in adult hearts. We employed an αMHC Cre transgene to delete NAE1, a subunit of the NEDD8 E1 enzyme, in the perinatal mouse heart. Cardiac-specific deletion of NAE1 (NAE1 CKO ) significantly decreased neddylated proteins in the heart. The NAE1 CKO mice displayed cardiac hypoplasia, ventricular non-compaction and heart failure during late gestation, which became more pronounced by postnatal day 1 and led to perinatal lethality. Mechanistically, genetic deletion or pharmacological inhibition of NAE1 resulted in accumulation of Hippo kinases Mst1 and LATS1/2, which in turn phosphorylated and inactivated YAP, a transcription cofactor necessary for cardiomyocyte proliferation, leading to dysregulation of a number of cell cycle-regulatory genes and blockade of cardiomyocyte proliferation in vivo and in vitro . Reactivation of YAP signaling by overexpression of a constitutively-active YAP mutant (YAP 5SA ), but not its wild-type counterpart, overcame the blockade of cardiomyocyte proliferation induced by inhibition of NAE1. Conclusions: Our findings establish the importance of neddylation in the heart, more specifically, in ventricular chamber maturation, and identify neddylation as a novel regulator of Hippo-YAP signaling to promote cardiomyocyte proliferation.


2021 ◽  
Author(s):  
Samantha C Chomyshen ◽  
Cheng-Wei Wu

Splicing of pre-mRNA is an essential process for dividing cells and splicing defects have been linked to aging and various chronic diseases. Environmental stress has recently been shown to alter splicing fidelity and molecular mechanisms that protect against splicing disruption remains unclear. Using an in vivo RNA splicing reporter, we performed a genome-wide RNAi screen in Caenorhabditis elegans and found that protein translation suppression via silencing of the conserved initiation factor 4G (IFG-1/eIF4G) protects against cadmium-induced splicing disruption. Transcriptome analysis of an ifg-1 deficient mutant revealed an overall increase in splicing fidelity and resistance towards cadmium-induced alternative splicing compared to the wild-type. We found that the ifg-1 mutant up-regulates >80 RNA splicing regulatory genes that are controlled by the TGF-β transcription factor SMA-2. The extended lifespan of the ifg-1 mutant is partially reduced upon sma-2 depletion and completely nullified when core spliceosome genes including snr-1, snr-2, and uaf-2 are knocked down. Together, these data describe a molecular mechanism that provides resistance towards stress-induced alternative splicing and demonstrate an essential role for RNA homeostasis in promoting longevity in a translation-compromised mutant.


Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 596 ◽  
Author(s):  
Haroon Butt ◽  
Agnieszka Piatek ◽  
Lixin Li ◽  
Anireddy S. N. Reddy ◽  
Magdy M. Mahfouz

Plant growth responds to various environmental and developmental cues via signaling cascades that influence gene expression at the level of transcription and pre-mRNA splicing. Alternative splicing of pre-mRNA increases the coding potential of the genome from multiexon genes and regulates gene expression through multiple mechanisms. Serine/arginine-rich (SR) proteins, a conserved family of splicing factors, are the key players of alternative splicing and regulate pre-mRNA splicing under stress conditions. The rice (Oryza sativa) genome encodes 22 SR proteins categorized into six subfamilies. Three of the subfamilies are plant-specific with no mammalian orthologues, and the functions of these SR proteins are not well known. The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is a genome engineering tool that cleaves the target DNA at specific locations directed by a guide RNA (gRNA). Recent advances in CRISPR/Cas9-mediated plant genome engineering make it possible to generate single and multiple functional knockout mutants in diverse plant species. In this study, we targeted each rice SR locus and produced single knockouts. To overcome the functional redundancy within each subfamily of SR genes, we utilized a polycistronic tRNA-gRNA multiplex targeting system and targeted all loci of each subfamily. Sanger sequencing results indicated that most of the targeted loci had knockout mutations. This study provides useful resource materials for understanding the molecular role of SR proteins in plant development and biotic and abiotic stress responses.


2021 ◽  
pp. 1-11
Author(s):  
Isabel Gómez-Redondo ◽  
Benjamín Planells ◽  
Paula Navarrete ◽  
Alfonso Gutiérrez-Adán

During the process of sex determination, a germ-cell-containing undifferentiated gonad is converted into either a male or a female reproductive organ. Both the composition of sex chromosomes and the environment determine sex in vertebrates. It is assumed that transcription level regulation drives this cascade of mechanisms; however, transcription factors can alter gene expression beyond transcription initiation by controlling pre-mRNA splicing and thereby mRNA isoform production. Using the key time window in sex determination and gonad development in mice, it has been reported that new non-transcriptional events, such as alternative splicing, could play a key role in sex determination in mammals. We know the role of key regulatory factors, like WT1(+/–KTS) or FGFR2(b/c) in pre-mRNA splicing and sex determination, indicating that important steps in the vertebrate sex determination process probably operate at a post-transcriptional level. Here, we discuss the role of pre-mRNA splicing regulators in sex determination in vertebrates, focusing on the new RNA-seq data reported from mice fetal gonadal transcriptome.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3878-3878 ◽  
Author(s):  
Minshi Wang ◽  
Zheng Ser ◽  
Shuyun Rao ◽  
Shawn Fahl ◽  
Yong Zhang ◽  
...  

Abstract Although it has long been reported that mutations in ribosome proteins (RP) are associated with increased cancer risk in humans, the molecular basis why which RP mutations do so remains unclear. Nevertheless, the prevailing view is that RP mutations, such as Rps19, are thought to alter transformation potential through general impairment of ribosome biogenesis or function. Importantly, recent observations are beginning to challenge this notion as too simplistic. We have determined that the RP, Rpl22, is not essential for ribosome biogenesis or global protein synthesis; however, its inactivation impairs the development of normal T lymphocytes and increases their transformation potential. Indeed, RPL22 is inactivated in human T acute lymphoblastic leukemia (T-ALL) and this is associated with reduced survival. Moreover, Rpl22-deficiency accelerates development of leukemia in a myristylated Akt2 transgenic (MyrAkt2 Tg) mouse model of T-ALL. To gain insight into how Rpl22 inactivation facilitates development of leukemia, we are performing unbiased transcriptomic and proteomic analysis on Rpl22+/+ and Rpl22-/- thymic lymphomas arising in the MyrAkt2 Tg model, and in an Rpl22-/- lymphoma reconstituted with Rpl22. Interestingly, relatively few changes in mRNA transcript read depth were observed; however, substantial differences in the proteome were observed. Pathway analysis revealed that the loss of Rpl22 altered the expression of proteins regulating RNA-processing, in particular RNA-splicing. Interestingly, interrogation of the transrciptome data for alternative splicing revealed that alterations in exon usage. The ability of Rpl22 to influence splicing appears to be conserved across species as alternative splicing was also observed in zebrafish embryos in which Rpl22 was knocked down using morpholino oligonucleotides. Consequently, we hypothesize that Rpl22 regulates biological events through its ability of binding to RNA targets, and controlling the expression of their protein products at least in part through altering mRNA splicing. How Rpl22 changes mRNA splicing pattern is currently under investigation. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 117 (10) ◽  
pp. 5269-5279 ◽  
Author(s):  
John W. Phillips ◽  
Yang Pan ◽  
Brandon L. Tsai ◽  
Zhijie Xie ◽  
Levon Demirdjian ◽  
...  

We sought to define the landscape of alternative pre-mRNA splicing in prostate cancers and the relationship of exon choice to known cancer driver alterations. To do so, we compiled a metadataset composed of 876 RNA-sequencing (RNA-Seq) samples from five publicly available sources representing a range of prostate phenotypes from normal tissue to drug-resistant metastases. We subjected these samples to exon-level analysis with rMATS-turbo, purpose-built software designed for large-scale analyses of splicing, and identified 13,149 high-confidence cassette exon events with variable incorporation across samples. We then developed a computational framework, pathway enrichment-guided activity study of alternative splicing (PEGASAS), to correlate transcriptional signatures of 50 different cancer driver pathways with these alternative splicing events. We discovered that Myc signaling was correlated with incorporation of a set of 1,039 cassette exons enriched in genes encoding RNA binding proteins. Using a human prostate epithelial transformation assay, we confirmed the Myc regulation of 147 of these exons, many of which introduced frameshifts or encoded premature stop codons. Our results connect changes in alternative pre-mRNA splicing to oncogenic alterations common in prostate and many other cancers. We also establish a role for Myc in regulating RNA splicing by controlling the incorporation of nonsense-mediated decay-determinant exons in genes encoding RNA binding proteins.


2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Marlin Touma ◽  
Xuedong Kang ◽  
Jae-Hyung Lee ◽  
Xinshu Xiao ◽  
Yibin Wang

Background: During postnatal maturation of mammalian heart the neonatal cardiomyocytes undergo dramatic changes including complete maturation, proliferation arrest, and terminal exit from the cell cycle (CC). However, transcriptome-wide analysis of CC programs has not been performed in perinatal stages among different cardiac chambers. In particular, the contribution of alternative RNA splicing to the chamber-specific CC activities is unexplored Design/Methods: To achieve comprehensive analysis of differential expression (DE) and alternative splicing (AS) of CC-related genes in left ventricle (LV) versus right ventricle (RV) during maturation deep RNA-seq was performed on male newborn mouse LV and RV at 3 time points of perinatal transition: P0, P3 and P7. Reads were mapped to mouse Transcriptome, and to mouse Genome. Transcriptome-Wide difference in inclusion of individual exons was performed using MATS. DE genes and AS variants were defined as those with fold change ≥2, at expression level ≥3 RBKM and a false discovery rate ≤0.05. Significant gene ontology (GO) terms were determined at P-value ≤0.05. Levels of expression were validated using qRT-PCR Results: Altogether, 2116 DE genes and 1162 AS events were observed. Among them, 109 CC-related genes were further analyzed. Distinct temporal patterns of DE and GO enrichment of CC genes in LV vs. RV during maturation were identified. Chamber -specific induction of genes involved in mitosis, karyokinesis, and cytokinesis was found at P7. RNA Splicing analysis of CC genes revealed 77 AS events. Skipping exon accounted for nearly half splicing events. Among 30 spliced exon variants, significant chamber-and temporal-specific inclusion were observed. Interestingly, the majority of AS variants exhibited opposing patterns of exon usage in RV vs. LV at p7 Conclusions: Our findings suggest novel molecular basis for chamber-specific programming of cellular proliferation and maturation in neonatal heart, including potential splicing regulation of dynamic exon enrichment of cell cycle related genes. Further functional studies to decipher putative splicing regulators of CC programming in LV vs. RV during maturation will likely lead to novel chamber-specific regenerative and therapeutic targets.


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