scholarly journals GT198 Splice Variants Display Dominant-Negative Activities and Are Induced by Inactivating Mutations

2013 ◽  
Vol 4 (1-2) ◽  
pp. 26-38 ◽  
Author(s):  
M. Peng ◽  
Z. Yang ◽  
H. Zhang ◽  
L. Jaafar ◽  
G. Wang ◽  
...  
Keyword(s):  
Splice Variants ◽  
Dominant Negative ◽  
Inactivating Mutations

Integration of FGF and TWIST in calvarial bone and suture development

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1845-1855 ◽  
Author(s):  
D.P. Rice ◽  
T. Aberg ◽  
Y. Chan ◽  
Z. Tang ◽  
P.J. Kettunen ◽  
...  
Keyword(s):  
Expression Analysis ◽  
Splice Variants ◽  
Bone Development ◽  
Dominant Negative ◽  
Calvarial Bone ◽  
Fgf Receptor ◽  
Helix Loop Helix ◽  
Suture Closure ◽  
Potential Ligand

Mutations in the FGFR1-FGFR3 and TWIST genes are known to cause craniosynostosis, the former by constitutive activation and the latter by haploinsufficiency. Although clinically achieving the same end result, the premature fusion of the calvarial bones, it is not known whether these genes lie in the same or independent pathways during calvarial bone development and later in suture closure. We have previously shown that Fgfr2c is expressed at the osteogenic fronts of the developing calvarial bones and that, when FGF is applied via beads to the osteogenic fronts, suture closure is accelerated (Kim, H.-J., Rice, D. P. C., Kettunen, P. J. and Thesleff, I. (1998) Development 125, 1241–1251). In order to investigate further the role of FGF signalling during mouse calvarial bone and suture development, we have performed detailed expression analysis of the splicing variants of Fgfr1-Fgfr3 and Fgfr4, as well as their potential ligand Fgf2. The IIIc splice variants of Fgfr1-Fgfr3 as well as the IIIb variant of Fgfr2 being expressed by differentiating osteoblasts at the osteogenic fronts (E15). In comparison to Fgf9, Fgf2 showed a more restricted expression pattern being primarily expressed in the sutural mesenchyme between the osteogenic fronts. We also carried out a detailed expression analysis of the helix-loop-helix factors (HLH) Twist and Id1 during calvaria and suture development (E10-P6). Twist and Id1 were expressed by early preosteoblasts, in patterns that overlapped those of the FGF ligands, but as these cells differentiated their expression dramatically decreased. Signalling pathways were further studied in vitro, in E15 mouse calvarial explants. Beads soaked in FGF2 induced Twist and inhibited Bsp, a marker of functioning osteoblasts. Meanwhile, BMP2 upregulated Id1. Id1 is a dominant negative HLH thought to inhibit basic HLH such as Twist. In Drosophila, the FGF receptor FR1 is known to be downstream of Twist. We demonstrated that in Twist(+/)(−) mice, FGFR2 protein expression was altered. We propose a model of osteoblast differentiation integrating Twist and FGF in the same pathway, in which FGF acts both at early and late stages. Disruption of this pathway may lead to craniosynostosis.

scholarly journals The type 2 anti-Müllerian hormone receptor has splice variants that are dominant-negative inhibitors

FEBS Letters ◽  
2013 ◽  
Vol 587 (12) ◽  
pp. 1749-1753 ◽  
Author(s):  
Floriane M. Imhoff ◽  
Dee Yang ◽  
Suneeth F. Mathew ◽  
Andrew N. Clarkson ◽  
Yui Kawagishi ◽  
...  
Keyword(s):  
Hormone Receptor ◽  
Splice Variants ◽  
Dominant Negative

scholarly journals Alternative Splice Variants Modulates Dominant-Negative Function of Helios in T-Cell Leukemia

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0163328 ◽  
Author(s):  
Shaorong Zhao ◽  
Wei Liu ◽  
Yinghui Li ◽  
Pengjiang Liu ◽  
Shufang Li ◽  
...  
Keyword(s):  
T Cell ◽  
Alternative Splice ◽  
Splice Variants ◽  
Dominant Negative ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Negative Function ◽  
Alternative Splice Variants

Expression of P73 Splice Variants Correlates to Resistance to DNA Damaging Drugs in Childhood T-Lineage Acute Lymphoblastic Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 995-995
Author(s):  
Marrit Meier ◽  
Monique L. Den Boer ◽  
Jules P.P. Meijerink ◽  
Monique Passier ◽  
Elisabeth R. Van Wering ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Mononuclear Cells ◽  
Splice Variants ◽  
Lymphoblastic Leukemia ◽  
Mrna Level ◽  
Dominant Negative ◽  
Leukemic Cells ◽  
Mrna Levels ◽  
Transactivation Domain ◽  
Loss Of Function

Abstract Children with T-lineage Acute Lymphoblastic Leukemia (T-ALL) have a higher relapse-risk and are in-vitro more resistant to therapeutic drugs compared to ALL patients with a precursor-B phenotype. Cellular resistance to anti-cancer agents has previously shown to be associated with failure of P53 family member signaling by abrogation of P53 function due to loss-of-function mutations or dominant-negative inhibition by isoforms of P73 lacking (part of) the N-terminal transactivation domain (P73ΔEX2, P73ΔEX2/3, ΔN-P73 and ΔN’-P73). Since p53 mutations are not commonly found in T-ALL, we investigated the expression levels of p73 splice variants in relation to drug resistance in children with T-ALL. Splice variants were quantitatively measured at the mRNA level in leukemic cells of 55 T-ALL patients and mononuclear cells of 12 non-leukemic controls. TA-p73 (transactivation competent), p73Δex2, p73Δex2/3, ΔN-p73 and ΔN’-p73 were all found to be present at a relatively higher mRNA level in T-ALL patients than controls (P < 0.05 for all), suggesting that expression of the TP73 gene is deregulated in T-ALL. Resistance of T-ALL cells to the DNA damaging drug daunorubicin correlated with mRNA levels of the dominant-negative variants of p73, i.e. ΔN-p73 and ΔN’-p73 (Rs = 0.38, P = 0.03). In contrast, expression of none of the variants, including ΔN-p73 and ΔN’-p73, was related to resistance of T-ALL cells to non-DNA damaging drugs (prednisolone, vincristine and L-asparaginase). In conclusion, high expression of ΔN-p73 and ΔN’-p73 variants possibly contributes to resistance to DNA damaging drugs in childhood T-ALL.

scholarly journals Associations between promoter usage and alternative splicing of the glucocorticoid receptor gene

2007 ◽  
Vol 38 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Henk Russcher ◽  
Virgil A S H Dalm ◽  
Frank H de Jong ◽  
Albert O Brinkmann ◽  
Leo J Hofland ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Splice Variants ◽  
Receptor Gene ◽  
Dominant Negative ◽  
Multiple Promoters ◽  
Glucocorticoid Receptor Gene ◽  
Dominant Negative Inhibitor ◽  
Exon 1 ◽  
Promoter Usage ◽  
Different Tissues

The glucocorticoid receptor (GR) is widely expressed in various tissues throughout the human body. At least three different 3′-splice variants of the GR have been reported: GR-α, which is functionally active; GR-β, which is a dominant negative inhibitor of GR-α function; and GR-P, which is thought to activate the function of GR-α. At least seven different variants for exon 1 exist, 1A–1F and 1H, each with its own promoter. In this study, we explored if tissue-specific splicing of the 3′-end variants of the GR is influenced by alternative promoter usage. cDNAs of different tissues and cell lines were used to investigate which part of transcripts carrying each of the three major variants for exons 1, 1A, 1B, or 1C, encodes for the splice variants GR-α, GR-β, and GR-P. Our data demonstrate that the expression of GR-α is preferentially regulated by promoter 1C and that for the expression of GR-P promoter 1B is predominantly used. This indicates that regulation of GR splice variants could partly occur through selective use of the multiple promoters, and that this is another way to sensitize cells and tissues to the different activities of the GR isoforms.

Cloning and characterization of dominant negative splice variants of the human histamine H4 receptor

2008 ◽  
Vol 414 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Richard M. van Rijn ◽  
André van Marle ◽  
Paul L. Chazot ◽  
Ellen Langemeijer ◽  
Yongjun Qin ◽  
...  
Keyword(s):  
Mast Cells ◽  
Mammalian Cells ◽  
Splice Variants ◽  
Inflammatory Diseases ◽  
Dominant Negative ◽  
Full Length ◽  
Dominant Negative Effect ◽  
Histamine H4 Receptor ◽  
Negative Effect ◽  
H4 Receptor

The H4R (histamine H4 receptor) is the latest identified member of the histamine receptor subfamily of GPCRs (G-protein-coupled receptors) with potential functional implications in inflammatory diseases and cancer. The H4R is primarily expressed in eosinophils and mast cells and has the highest homology with the H3R. The occurrence of at least twenty different hH3R (human H3R) isoforms led us to investigate the possible existence of H4R splice variants. In the present paper, we report on the cloning of the first two alternatively spliced H4R isoforms from CD34+ cord blood-cell-derived eosinophils and mast cells. These H4R splice variants are localized predominantly intracellularly when expressed recombinantly in mammalian cells. We failed to detect any ligand binding, H4R–ligand induced signalling or constitutive activity for these H4R splice variants. However, when co-expressed with full-length H4R [H4R(390) (H4R isoform of 390 amino acids)], the H4R splice variants have a dominant negative effect on the surface expression of H4R(390). We detected H4R(390)–H4R splice varianthetero-oligomers by employing both biochemical (immunoprecipitation and cell-surface labelling) and biophysical [time-resolved FRET (fluorescence resonance energy transfer)] techniques. mRNAs encoding the H4R splice variants were detected in various cell types and expressed at similar levels to the full-length H4R(390) mRNA in, for example, pre-monocytes. We conclude that the H4R splice variants described here have a dominant negative effect on H4R(390) functionality, as they are able to retain H4R(390) intracellularly and inactivate a population of H4R(390), presumably via hetero-oligomerization.

scholarly journals Inhibitors of Copi and Copii Do Not Block PEX3-Mediated Peroxisome Synthesis

2000 ◽  
Vol 149 (7) ◽  
pp. 1345-1360 ◽  
Author(s):  
Sarah T. South ◽  
Katherine A. Sacksteder ◽  
Xiaoling Li ◽  
Yifei Liu ◽  
Stephen J. Gould
Keyword(s):  
Membrane Proteins ◽  
Zellweger Syndrome ◽  
Brefeldin A ◽  
Membrane Traffic ◽  
Dominant Negative ◽  
Peroxisome Biogenesis ◽  
Membrane Synthesis ◽  
Peroxisomal Membrane ◽  
Peroxisome Membrane ◽  
Inactivating Mutations

In humans, defects in peroxisome biogenesis are the cause of lethal diseases typified by Zellweger syndrome. Here, we show that inactivating mutations in human PEX3 cause Zellweger syndrome, abrogate peroxisome membrane synthesis, and result in reduced abundance of peroxisomal membrane proteins (PMPs) and/or mislocalization of PMPs to the mitochondria. Previous studies have suggested that PEX3 may traffic through the ER en route to the peroxisome, that the COPI inhibitor, brefeldin A, leads to accumulation of PEX3 in the ER, and that PEX3 overexpression alters the morphology of the ER. However, we were unable to detect PEX3 in the ER at early times after expression. Furthermore, we find that inhibition of COPI function by brefeldin A has no effect on trafficking of PEX3 to peroxisomes and does not inhibit PEX3-mediated peroxisome biogenesis. We also find that inhibition of COPII-dependent membrane traffic by a dominant negative SAR1 mutant fails to block PEX3 transport to peroxisomes and PEX3-mediated peroxisome synthesis. Based on these results, we propose that PEX3 targeting to peroxisomes and PEX3-mediated peroxisome membrane synthesis may occur independently of COPI- and COPII-dependent membrane traffic.

Venus Fly Trap Domain of mGluR1 Functions as a Dominant Negative Against Group I mGluR Signaling

2010 ◽  
Vol 104 (1) ◽  
pp. 439-448 ◽  
Author(s):  
Donald Beqollari ◽  
Paul J. Kammermeier
Keyword(s):  
Cell Surface ◽  
Metabotropic Glutamate Receptors ◽  
Splice Variants ◽  
Dominant Negative ◽  
Full Length ◽  
Calcium Currents ◽  
Metabotropic Glutamate ◽  
Group I ◽  
Cervical Ganglion ◽  
Covalently Linked

Metabotropic glutamate receptors (mGluRs) form covalently linked homodimers and contain large, N-terminal extracellular ligand binding, “venus fly trap” (VFT) domains. These domains, when expressed separately, are secreted as disulfide linked dimers and can dimerize with full-length receptors. mGluR splice variants have been described that contain only this domain, but the consequences of their interaction on receptor signaling have not been explored. Here it is shown that an mGluR1 mutant containing only the VFT is retained on the cell surface when a full-length receptor is co-expressed. Further, when expressed in rat superior cervical ganglion (SCG) neurons and modulation of native calcium currents is used as an assay for receptor activity, the VFT acts as a dominant negative with respect to mGluR1 signaling. Although full-length mGluR1 and mGluR5 are not known to heterodimerize, the mGluR5 VFT partially occludes mGluR1 signaling and the mGluR1 VFT potently occludes mGluR5 signaling in SCG neurons. In addition, an mGluR1 point mutant, mGluR1 C140G, which cannot covalently dimerize, functions like the wild-type receptor when expressed alone. The C140G mutant is inhibited by the mGluR1 VFT construct but does not retain the mGluR1 VFT on the cell surface, suggesting that the loss of C140 renders the interaction reversible. Finally, a peptide designed to disrupt mGluR1 dimerization reduced signaling through the C140G mutant receptor, but only when applied intracellularly for several hours, indicating that loss of signaling requires disruption of dimerization prior to plasma membrane insertion.

scholarly journals Targeting the GA Binding Protein β1L Isoform Does Not Perturb Lymphocyte Development and Function

2008 ◽  
Vol 28 (13) ◽  
pp. 4300-4309 ◽  
Author(s):  
Hai-Hui Xue ◽  
Xuefang Jing ◽  
Julie Bollenbacher-Reilley ◽  
Dong-Mei Zhao ◽  
Jodie S. Haring ◽  
...  
Keyword(s):  
B Cells ◽  
Target Genes ◽  
Splice Variants ◽  
Binding Protein ◽  
Critical Role ◽  
Dominant Negative ◽  
T And B Cells ◽  
Carboxy Terminal ◽  
And Function ◽  
Ga Binding Protein

ABSTRACT GA binding protein (GABP) is a ubiquitously expressed Ets family transcription factor that consists of two subunits, GABPα and GABPβ. GABPα binds to DNA, and GABPβ heterodimerizes with GABPα and possesses the ability to transactivate target genes. Our previous studies using GABPα-deficient mice revealed that GABPα is required for the development of both T and B cells. Two splice variants of GABPβ are generated from the Gabpb1 locus and differ in their carboxy-terminal lengths and sequences. The longer isoform (GABPβ1L) can homodimerize and thus form α2β2 tetramers depending on the gene context, whereas the shorter isoform (GABPβ1S) cannot. In this study, we generated mice that are deficient in GABPβ1L but that retain the expression of GABPβ1S. Surprisingly, GABPβ1L−/− mice had normal T- and B-cell development, and mature T and B cells showed normal responses to various stimuli. In contrast, targeting both GABPβ1L and GABPβ1S resulted in early embryonic lethality. Because of its incapability of forming homodimers, GABPβ1S has been suspected to have a dominant negative role in regulating GABP target genes. Our findings argue against such a possibility and rather suggest that GABPβ1S has a critical role in maintaining the transcriptional activity of the GABPα/β complex.

scholarly journals Cloning, Expression, and Functional Characterization of Relaxin Receptor (Leucine-Rich Repeat-Containing G Protein-Coupled Receptor 7) Splice Variants from Human Fetal Membranes

Endocrinology ◽  
2007 ◽  
Vol 149 (3) ◽  
pp. 1277-1294 ◽  
Author(s):  
András Kern ◽  
Daniela Hubbard ◽  
Aaron Amano ◽  
Gillian D. Bryant-Greenwood
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
G Protein ◽  
Splice Variant ◽  
Splice Variants ◽  
Dominant Negative ◽  
Fetal Membranes ◽  
Leucine Rich Repeat ◽  
G Protein Coupled ◽  
Relaxin Receptor

The relaxin receptor [leucine-rich repeat-containing G protein-coupled receptor 7 (LGR7)] belongs to the leucine-rich repeat containing G protein-coupled receptors subgroup C. Three new LGR7 splice variants have been cloned from the human fetal membranes and shown to be truncated versions of the full-length receptor, encoded by different lengths of the extracellular domain. The expression of their mRNAs has been confirmed by both qualitative and quantitative PCR and shown to be higher in the chorion and decidua before, compared with after, spontaneous labor. When HEK293 cells were transfected with each LGR7 splice variant, their proteins were retained within the endoplasmic reticulum. However, the protein for the shortest variant was also secreted into the medium. We have characterized the intracellular functions and effects of these LGR7 variants on the function of the wild-type (WT)-LGR7. In coexpression studies, each splice variant interacted directly with the WT-LGR7 and exerted a dominant-negative effect on cAMP accumulation by the WT-LGR7 after relaxin treatment. This interaction resulted in the sequestration of the WT-LGR7 inside the cells by down-regulation of its maturation and cell surface delivery. The constitutive homodimerization of WT-LGR7 has been shown here to take place in the endoplasmic reticulum, and the presence of any one of the splice variants decreased this by the formation of heterodimers with the WT-LGR7, supporting the view that homodimerization is a prerequisite for receptor trafficking to the cell surface. These data suggest that the dominant-negative effects of the LGR7 splice variants expressed in the chorion and decidua could be functionally significant in the peripartal period by inhibiting the function of WT-LGR7 and dampening the responsiveness of these tissues to endogenous relaxin.

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