scholarly journals Inhibition of a transcriptional repressor rescues hearing in a splicing factor–deficient mouse

2020 ◽  
Vol 3 (12) ◽  
pp. e202000841
Author(s):  
Yoko Nakano ◽  
Susan Wiechert ◽  
Bernd Fritzsch ◽  
Botond Bánfi
Keyword(s):  
Alternative Splicing ◽  
Target Genes ◽  
Transcriptional Repressor ◽  
Dominant Negative ◽  
Splicing Factor ◽  
Loss Of Function ◽  
Transgenic Expression ◽  
Mechanosensory Hair Cells

In mechanosensory hair cells (HCs) of the ear, the transcriptional repressor REST is continuously inactivated by alternative splicing of its pre-mRNA. This mechanism of REST inactivation is crucial for hearing in humans and mice. Rest is one of many pre-mRNAs whose alternative splicing is regulated by the splicing factor SRRM4; Srrm4 loss-of-function mutation in mice (Srrm4bv/bv) causes deafness, balance defects, and degeneration of all HC types other than the outer HCs (OHCs). The specific splicing alterations that drive HC degeneration in Srrm4bv/bv mice are unknown, and the mechanism underlying SRRM4-independent survival of OHCs is undefined. Here, we show that transgenic expression of a dominant-negative REST fragment in Srrm4bv/bv mice is sufficient for long-term rescue of hearing, balancing, HCs, alternative splicing of Rest, and expression of REST target genes including the Srrm4 paralog Srrm3. We also show that in HCs, SRRM3 regulates many of the same exons as SRRM4; OHCs are unique among HCs in that they transiently down-regulate Rest transcription as they mature to express Srrm3 independently of SRRM4; and simultaneous SRRM4–SRRM3 deficiency causes complete HC loss by preventing inactivation of REST in all HCs. Thus, our data reveal that REST inactivation is the primary and essential role of SRRM4 in the ear, and that OHCs differ from other HCs in the SRRM4-independent expression of the functionally SRRM4-like splicing factor SRRM3.

scholarly journals Role of Arabidopsis Splicing factor SF1 in Temperature-Responsive Alternative Splicing of FLM pre-mRNA

2020 ◽  
Vol 11 ◽  
Author(s):  
Keh Chien Lee ◽  
Kyung Sook Chung ◽  
Hee Tae Lee ◽  
Jae-Hyeok Park ◽  
Jeong Hwan Lee ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Flowering Time ◽  
Crop Yields ◽  
Transcript Level ◽  
Splicing Factor ◽  
Loss Of Function ◽  
Temperature Dependent ◽  
Temperature Responsive ◽  
Different Temperatures

Small changes in temperature affect plant ecological and physiological factors that impact agricultural production. Hence, understanding how temperature affects flowering is crucial for decreasing the effects of climate change on crop yields. Recent reports have shown that FLM-β, the major spliced isoform of FLOWERING LOCUS M (FLM)—a flowering time gene, contributes to temperature-responsive flowering in Arabidopsis thaliana. However, the molecular mechanism linking pre-mRNA processing and temperature-responsive flowering is not well understood. Genetic and molecular analyses identified the role of an Arabidopsis splicing factor SF1 homolog, AtSF1, in regulating temperature-responsive flowering. The loss-of-function AtSF1 mutant shows temperature insensitivity at different temperatures and very low levels of FLM-β transcript, but a significantly increased transcript level of the alternative splicing (AS) isoform, FLM-δ. An RNA immunoprecipitation (RIP) assay revealed that AtSF1 is responsible for ambient temperature-dependent AS of FLM pre-mRNA, resulting in the temperature-dependent production of functional FLM-β transcripts. Moreover, alterations in other splicing factors such as ABA HYPERSENSITIVE1/CBP80 (ABH1/CBP80) and STABILIZED1 (STA1) did not impact the FLM-β/FLM-δ ratio at different temperatures. Taken together, our data suggest that a temperature-dependent interaction between AtSF1 and FLM pre-mRNA controls flowering time in response to temperature fluctuations.

scholarly journals Waterlogging-Stress-Responsive LncRNAs, Their Regulatory Relationships with MiRNAs and Target Genes in Cucumber (Cucumis sativus L.)

2021 ◽  
Vol 22 (15) ◽  
pp. 8197
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Adela Adamus ◽  
Małgorzata Czernicka
Keyword(s):  
Target Genes ◽  
Recovery Period ◽  
Sufficient Information ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Cucumis Sativus L ◽  
Waterlogging Stress ◽  
Non Coding Rna

Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber.

The role of Xenopus dickkopf1 in prechordal plate specification and neural patterning

Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4981-4992 ◽  
Author(s):  
O. Kazanskaya ◽  
A. Glinka ◽  
C. Niehrs
Keyword(s):  
Target Genes ◽  
Loss Of Function ◽  
Dorsoventral Patterning ◽  
Gastrula Stage ◽  
Neural Patterning ◽  
Prechordal Plate ◽  
Wnt Inhibitor ◽  
The Central Nervous System ◽  
Wnt Inhibitors

Dickkopf1 (dkk1) encodes a secreted WNT inhibitor expressed in Spemann's organizer, which has been implicated in head induction in Xenopus. Here we have analyzed the role of dkk1 in endomesoderm specification and neural patterning by gain- and loss-of-function approaches. We find that dkk1, unlike other WNT inhibitors, is able to induce functional prechordal plate, which explains its ability to induce secondary heads with bilateral eyes. This may be due to differential WNT inhibition since dkk1, unlike frzb, inhibits Wnt3a signalling. Injection of inhibitory antiDkk1 antibodies reveals that dkk1 is not only sufficient but also required for prechordal plate formation but not for notochord formation. In the neural plate dkk1 is required for anteroposterior and dorsoventral patterning between mes- and telencephalon, where dkk1 promotes anterior and ventral fates. Both the requirement of anterior explants for dkk1 function and their ability to respond to dkk1 terminate at late gastrula stage. Xenopus embryos posteriorized with bFGF, BMP4 and Smads are rescued by dkk1. dkk1 does not interfere with the ability of bFGF to induce its immediate early target gene Xbra, indicating that its effect is indirect. In contrast, there is cross-talk between BMP and WNT signalling, since induction of BMP target genes is sensitive to WNT inhibitors until the early gastrula stage. Embryos treated with retinoic acid (RA) are not rescued by dkk1 and RA affects the central nervous system (CNS) more posterior than dkk1, suggesting that WNTs and retinoids may act to pattern anterior and posterior CNS, respectively, during gastrulation.

scholarly journals Impaired cytoplasmic domain interactions cause co-assembly defect and loss of function in the p.Glu293Lys KNCJ2 variant isolated from an Andersen–Tawil syndrome patient

2020 ◽  
Author(s):  
Szilvia Déri ◽  
János Borbás ◽  
Teodóra Hartai ◽  
Lidia Hategan ◽  
Beáta Csányi ◽  
...  
Keyword(s):  
Salt Bridge ◽  
Cytoplasmic Domain ◽  
Inward Rectifier ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Causative Role ◽  
Loss Of Function ◽  
Subunit Interactions ◽  
Negative Effect

Abstract Aims Subunit interactions at the cytoplasmic domain interface (CD-I) have recently been shown to control gating in inward rectifier potassium channels. Here we report the novel KCNJ2 variant p.Glu293Lys that has been found in a patient with Andersen–Tawil syndrome type 1 (ATS1), causing amino acid substitution at the CD-I of the inward rectifier potassium channel subunit Kir2.1. Neither has the role of Glu293 in gating control been investigated nor has a pathogenic variant been described at this position. This study aimed to assess the involvement of Glu293 in CD-I subunit interactions and to establish the pathogenic role of the p.Glu293Lys variant in ATS1. Methods and results The p.Glu293Lys variant produced no current in homomeric form and showed dominant-negative effect over wild-type (WT) subunits. Immunocytochemical labelling showed the p.Glu293Lys subunits to distribute in the subsarcolemmal space. Salt bridge prediction indicated the presence of an intersubunit salt bridge network at the CD-I of Kir2.1, with the involvement of Glu293. Subunit interactions were studied by the NanoLuc® Binary Technology (NanoBiT) split reporter assay. Reporter constructs carrying NanoBiT tags on the intracellular termini produced no bioluminescent signal above background with the p.Glu293Lys variant in homomeric configuration and significantly reduced signals in cells co-expressing WT and p.Glu293Lys subunits simultaneously. Extracellularly presented reporter tags, however, generated comparable bioluminescent signals with heteromeric WT and p.Glu293Lys subunits and with homomeric WT channels. Conclusions Loss of function and dominant-negative effect confirm the causative role of p.Glu293Lys in ATS1. Co-assembly of Kir2.1 subunits is impaired in homomeric channels consisting of p.Glu293Lys subunits and is partially rescued in heteromeric complexes of WT and p.Glu293Lys Kir2.1 variants. These data point to an important role of Glu293 in mediating subunit assembly, as well as in gating of Kir2.1 channels.

scholarly journals Maternal Exposure to High-Fat Diet Induces Long-Term Derepressive Chromatin Marks in the Heart

Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 181 ◽  
Author(s):  
Guillaume Blin ◽  
Marjorie Liand ◽  
Claire Mauduit ◽  
Hassib Chehade ◽  
Mohamed Benahmed ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Heart Development ◽  
High Fat Diet ◽  
Target Genes ◽  
Critical Role ◽  
Maternal Exposure ◽  
High Fat ◽  
Cardiac Alterations

Heart diseases are a leading cause of death. While the link between early exposure to nutritional excess and heart disease risk is clear, the molecular mechanisms involved are poorly understood. In the developmental programming field, increasing evidence is pointing out the critical role of epigenetic mechanisms. Among them, polycomb repressive complex 2 (PRC2) and DNA methylation play a critical role in heart development and pathogenesis. In this context, we aimed at evaluating the role of these epigenetic marks in the long-term cardiac alterations induced by early dietary challenge. Using a model of rats exposed to maternal high-fat diet during gestation and lactation, we evaluated cardiac alterations at adulthood. Expression levels of PRC2 components, its histone marks di- and trimethylated histone H3 (H3K27me2/3), associated histone mark (ubiquitinated histone H2A, H2AK119ub1) and target genes were measured by Western blot. Global DNA methylation level and DNA methyl transferase 3B (DNMT3B) protein levels were measured. Maternal high-fat diet decreased H3K27me3, H2Ak119ub1 and DNA methylation levels, down-regulated the enhancer of zeste homolog 2 (EZH2), and DNMT3B expression. The levels of the target genes, isl lim homeobox 1 (Isl1), six homeobox 1 (Six1) and mads box transcription enhancer factor 2, polypeptide C (Mef2c), involved in cardiac pathogenesis were up regulated. Overall, our data suggest that the programming of cardiac alterations by maternal exposure to high-fat diet involves the derepression of pro-fibrotic and pro-hypertrophic genes through the induction of EZH2 and DNMT3B deficiency.

scholarly journals Comprehensive genomic screens identify a role for PLZF-RARα as a positive regulator of cell proliferation via direct regulation of c-MYC

Blood ◽  
2009 ◽  
Vol 114 (27) ◽  
pp. 5499-5511 ◽  
Author(s):  
Kim L. Rice ◽  
Itsaso Hormaeche ◽  
Sergei Doulatov ◽  
Jared M. Flatow ◽  
David Grimwade ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Target Genes ◽  
Retinoic Acid Receptor ◽  
Promyelocytic Leukemia ◽  
Dominant Negative ◽  
Myeloid Leukemias ◽  
Direct Target ◽  
Retinoic Acid Receptor Α ◽  
Chip Chip

Abstract The t(11;17)(q23;q21) translocation is associated with a retinoic acid (RA)–insensitive form of acute promyelocytic leukemia (APL), involving the production of reciprocal fusion proteins, promyelocytic leukemia zinc finger–retinoic acid receptor α (PLZF-RARα) and RARα-PLZF. Using a combination of chromatin immunoprecipitation promotor arrays (ChIP-chip) and gene expression profiling, we identify novel, direct target genes of PLZF-RARα that tend to be repressed in APL compared with other myeloid leukemias, supporting the role of PLZF-RARα as an aberrant repressor in APL. In primary murine hematopoietic progenitors, PLZF-RARα promotes cell growth, and represses Dusp6 and Cdkn2d, while inducing c-Myc expression, consistent with its role in leukemogenesis. PLZF-RARα binds to a region of the c-MYC promoter overlapping a functional PLZF site and antagonizes PLZF-mediated repression, suggesting that PLZF-RARα may act as a dominant-negative version of PLZF by affecting the regulation of shared targets. RA induced the differentiation of PLZF-RARα–transformed murine hematopoietic cells and reduced the frequency of clonogenic progenitors, concomitant with c-Myc down-regulation. Surviving RA-treated cells retained the ability to be replated and this was associated with sustained c-Myc expression and repression of Dusp6, suggesting a role for these genes in maintaining a self-renewal pathway triggered by PLZF-RARα.

A Microrna Feed-Forward Loop Amplifies GFI1N382S Transcriptional Reprogramming In Severe Congenital Neutropenia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2239-2239
Author(s):  
Chinavenmeni Subramani Velu ◽  
Avedis Kazanjian ◽  
Clemencia Colmenares ◽  
H. Leighton Grimes
Keyword(s):  
Bone Marrow ◽  
Target Genes ◽  
Bone Marrow Cells ◽  
Transcriptional Repressor ◽  
Dominant Negative ◽  
Severe Congenital Neutropenia ◽  
Congenital Neutropenia ◽  
Feed Forward ◽  
Marrow Cells ◽  
Myeloid Progenitors

Abstract Abstract 2239 The Growth factor independent -1 (Gfi1) transcriptional repressor regulates both hematopoietic stem cell self renewal and myeloid differentiation. Humans with severe congenital neutropenia (SCN) display mutations in GFI1 that generate dominant negative acting proteins. Moreover, GFI1-mutant SCN patients and Gfi1-/- mice display a unique accumulation of myeloid progenitors. Recently we showed that Gfi1 regulation of HoxA9, Pbx1 and Meis1 underlies these phenomena, in that the Gfi1-Hox transcriptional circuit controls the accumulation of myeloid progenitors in vivo. We have also shown that Gfi1 regulates miR-21 during myelopoiesis, and that miR-21 is deregulated by Gfi1N382S expression. Our new data link these concepts by demonstrating that forced expression of miR-21 in bone marrow cells results in the accumulation of myeloid progenitors in transplant recipients. Moreover, miR-21 directly targets the Ski oncoprotein, and Ski-/- bone marrow cells show an accumulation of myeloid progenitors. Thus, Gfi1-/-, miR-21 overexpressing-, and Ski-/- myeloid progenitors accumulate in the marrow. Strikingly, Ski is dramatically reduced in miR-21 overexpressing Lin- bone marrow cells. Nearly undetectable Ski expression in Gfi1-/- bone marrow cells can be completely rescued by antagonizing miR-21 activity. Since Ski is a corepressor and Gfi1 is a transcriptional repressor, we next tested whether the two proteins physically interact. Indeed, endogenous Ski and Gfi1 can be coimmunoprecipitated. Synthetic Ski and Gfi1 proteins reveal that the interaction is mediated through Ski carboxy-terminal and Gfi1 zinc-finger domains. Chromatin immunoprecipitation reveals Ski and Gfi1 co-occupy several Gfi1 target genes (including HoxA9), which are derepressed upon Gfi1 or Ski knockdown. However, while Gfi1 binds and regulates the miR-21 gene, Ski is not bound to the miR-21 gene, and Ski knockdown has no effect upon miR-21 levels. Thus, the data point to a novel feed-forward transcriptional circuit. Gfi1N382S deregulation of miR-21 amplifies the dominant-negative effect of Gfi1N382S through miR-21 targeting of Ski, leading to further derepression of Gfi1-Ski target genes. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Nrf Transcription Factors in Keratinocytes Are Essential for Skin Tumor Prevention but Not for Wound Healing

2006 ◽  
Vol 26 (10) ◽  
pp. 3773-3784 ◽  
Author(s):  
Ulrich auf dem Keller ◽  
Marcel Huber ◽  
Tobias A. Beyer ◽  
Angelika Kümin ◽  
Christina Siemes ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Wound Repair ◽  
Target Genes ◽  
Dominant Negative ◽  
Skin Tumor ◽  
Cellular Stress Response ◽  
Skin Development

ABSTRACT The Nrf2 transcription factor is a key player in the cellular stress response through its regulation of cytoprotective genes. In this study we determined the role of Nrf2-mediated gene expression in keratinocytes for skin development, wound repair, and skin carcinogenesis. To overcome compensation by the related Nrf1 and Nrf3 proteins, we expressed a dominant-negative Nrf2 mutant (dnNrf2) in the epidermis of transgenic mice. The functionality of the transgene product was verified in vivo using mice doubly transgenic for dnNrf2 and an Nrf2-responsive reporter gene. Surprisingly, no abnormalities of the epidermis were observed in dnNrf2-transgenic mice, and even full-thickness skin wounds healed normally. However, the onset, incidence, and multiplicity of chemically induced skin papillomas were strikingly enhanced, whereas the progression to squamous cell carcinomas was unaltered. We provide evidence that the enhanced tumorigenesis results from reduced basal expression of cytoprotective Nrf target genes, leading to accumulation of oxidative damage and reduced carcinogen detoxification. Our results reveal a crucial role of Nrf-mediated gene expression in keratinocytes in the prevention of skin tumors and suggest that activation of Nrf2 in keratinocytes is a promising strategy to prevent carcinogenesis of this highly exposed organ.

scholarly journals Dependency of human and murine LKB1-inactivated lung cancer on aberrant CRTC-CREB activation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Xin Zhou ◽  
Jennifer W Li ◽  
Zirong Chen ◽  
Wei Ni ◽  
Xuehui Li ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Expression Patterns ◽  
Direct Proof ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Loss Of Function ◽  
Creb Activation ◽  
Interaction Interface ◽  
Lkb1 Tumor Suppressor

Lung cancer with loss-of-function of the LKB1 tumor suppressor is a common aggressive subgroup with no effective therapies. LKB1-deficiency induces constitutive activation of cAMP/CREB-mediated transcription by a family of three CREB-regulated transcription coactivators (CRTC1-3). However, the significance and mechanism of CRTC activation in promoting the aggressive phenotype of LKB1-null cancer remain poorly characterized. Here we observed overlapping CRTC expression patterns and mild growth phenotypes of individual CRTC-knockouts in lung cancer, suggesting functional redundancy of CRTC1-3. We consequently designed a dominant-negative mutant (dnCRTC) to block all three CRTCs to bind and co-activate CREB. Expression of dnCRTC efficiently inhibited the aberrantly activated cAMP/CREB-mediated oncogenic transcriptional program induced by LKB1-deficiency, and specifically blocked the growth of human and murine LKB1-inactivated lung cancer. Collectively, this study provides direct proof for an essential role of the CRTC-CREB activation in promoting the malignant phenotypes of LKB1-null lung cancer and proposes the CRTC-CREB interaction interface as a novel therapeutic target.

scholarly journals Hnrnpul1 loss of function affects skeletal and limb development

2020 ◽  
Author(s):  
Danielle L Blackwell ◽  
Sherri D Fraser ◽  
Oana Caluseriu ◽  
Claudia Vivori ◽  
Paul MK Gordon ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Limb Development ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleic Acid Binding ◽  
Loss Of Function ◽  
Zebrafish Model ◽  
Dna And Rna ◽  
Developmental Role

AbstractMutations in RNA binding proteins can lead to pleiotropic phenotypes including craniofacial, skeletal, limb and neurological symptoms. Heterogeneous Nuclear Ribonucleoproteins (hnRNPs) are involved in nucleic acid binding, transcription and splicing through direct binding to DNA and RNA, or through interaction with other proteins in the spliceosome. Here, we show a developmental role for hnrnpul1 in zebrafish fin and craniofacial development, and in adult onset scoliosis. Furthermore, we demonstrate a role of hnrnpul1 in alternative splicing regulation. In two siblings with congenital limb malformations, whole exome sequencing detected a frameshift variant in HNRNPUL1; the developmental role of this gene in humans has not been explored. Our data suggest an important developmental role of hnRNPUL1 in both zebrafish and humans. Although there are differences in phenotypes between species, our data suggests potential conservation of ancient regulatory circuits involving hnRNPUL1 in these phylogenetically distant species.Summary statementA zebrafish model of loss of Hnrnpul1 shows alternative splicing defects and results in limb growth, craniofacial tendon, and skeletal anomalies.

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