scholarly journals Dominant gain-of-function STAT1 mutations in FOXP3 wild-type immune dysregulation–polyendocrinopathy–enteropathy–X-linked–like syndrome

2013 ◽  
Vol 131 (6) ◽  
pp. 1611-1623.e3 ◽  
Author(s):  
Gulbu Uzel ◽  
Elizabeth P. Sampaio ◽  
Monica G. Lawrence ◽  
Amy P. Hsu ◽  
Mary Hackett ◽  
...  
Keyword(s):  
Immune Dysregulation ◽  
Wild Type ◽  
Gain Of Function

The Drosophila gene Bearded encodes a novel small protein and shares 3′ UTR sequence motifs with multiple Enhancer of split complex genes

Development ◽  
1997 ◽  
Vol 124 (20) ◽  
pp. 4039-4051 ◽  
Author(s):  
M.W. Leviten ◽  
E.C. Lai ◽  
J.W. Posakony
Keyword(s):  
Sequence Similarity ◽  
Notch Pathway ◽  
Alpha Helix ◽  
Sequence Motifs ◽  
Wild Type ◽  
Gain Of Function ◽  
Small Protein ◽  
Drosophila Gene ◽  
Amphipathic Alpha Helix ◽  
Enhancer Of Split

Gain-of-function alleles of the Drosophila gene Bearded (Brd) cause sensory organ multiplication and loss phenotypes indistinguishable at the cellular level from those caused by loss-of-function mutations in the genes of the Notch pathway (Leviten, M. W. and Posakony, J. W. (1996). Dev. Biol. 176, 264–283). We have carried out a molecular analysis of the structure and expression of both wild-type and mutant Brd transcription units. We find that the Brd transcript is truncated and accumulates to substantially higher levels in the gain-of-function mutants, due to the insertion of a transposable element of the blood family in the Brd 3′ untranslated region (UTR). The wild-type Brd 3′ UTR includes three copies of a 9-nucleotide sequence (CAGCTTTAA) that we refer to as the ‘Brd box’. Moreover, the 3′ UTRs of Brd and of the m4 transcription unit of the Enhancer of split gene complex [E(spl)-C] exhibit an unusually high degree of sequence identity that includes not only Brd box sequences but also a second motif we refer to as the ‘GY box’ (GTCTTCC). We find that both the Brd box and the GY box are also present in the 3′ UTRs of several basic helix-loop-helix repressor-encoding genes of the E(spl)-C, often in multiple copies, suggesting that a novel mode of post-transcriptional regulation applies to Brd and many E(spl)-C genes. The fact that the more abundant Brd mutant mRNA lacks the GY box and two of the Brd boxes present in wild-type Brd mRNA suggests that either or both of these elements may confer instability on transcripts that contain them. Finally, we find that Brd encodes a novel small protein of only 81 amino acids that is predicted to include a basic amphipathic alpha-helix. The deduced Brd protein shows sequence similarity to the E(spl)m4 protein, which is likewise expected to include a basic amphipathic alpha-helix, suggesting that the two proteins have related biochemical functions.

Cardiac expression of a gain-of-function α5-integrin results in perinatal lethality

2001 ◽  
Vol 280 (1) ◽  
pp. H361-H367 ◽  
Author(s):  
Maria L. Valencik ◽  
John A. McDonald
Keyword(s):  
Cardiac Development ◽  
Wild Type ◽  
Integrin Receptors ◽  
Gain Of Function ◽  
Transgenic Expression ◽  
Physiological Regulation ◽  
Myocyte Differentiation ◽  
Perinatal Lethality ◽  
And Function

Communication between the extracellular matrix and the intracellular signal transduction and cytoskeletal system is mediated by integrin receptors. α5β1-Integrin and its cognate ligand fibronectin are essential in development of mesodermal structures, myocyte differentiation, and normal cardiac development. To begin to explore the potential roles of α5β1-integrin specifically in cardiomyocytes, we used a transgenic expression strategy. We overexpressed two forms of the human α5-integrin in cardiomyocytes: the full-length wild-type α5-integrin and a putative gain-of-function mutation created by truncating the cytoplasmic domain, designated α5-1-integrin. Overexpression of the wild-type α5-integrin has no detectable adverse effects in the mouse, whereas expression of α5-1-integrin caused electrocardiographic abnormalities, fibrotic changes in the ventricle, and perinatal lethality. Thus physiological regulation of integrin function appears essential for maintenance of normal cardiomyocyte structure and function. This strengthens the role of inside-out signaling in regulation of integrins in vivo and suggests that integrins and associated signaling molecules are important in cardiomyocyte function.

scholarly journals Mutant p53 Sequestration of the MDM2 Acidic Domain Inhibits E3 Ligase Activity

2018 ◽  
Vol 39 (4) ◽  
Author(s):  
Leixiang Yang ◽  
Tanjing Song ◽  
Qian Cheng ◽  
Lihong Chen ◽  
Jiandong Chen
Keyword(s):  
Tumor Cells ◽  
Recent Work ◽  
Intramolecular Interaction ◽  
E3 Ligase ◽  
Mutant P53 ◽  
Wild Type ◽  
Gain Of Function ◽  
Core Domain ◽  
Acidic Domain ◽  
Wild Type P53

ABSTRACT Missense p53 mutants often accumulate in tumors and drive progression through gain of function. MDM2 efficiently degrades wild-type p53 but fails to degrade mutant p53 in tumor cells. Previous studies revealed that mutant p53 inhibits MDM2 autoubiquitination, suggesting that the interaction inhibits MDM2 E3 activity. Recent work showed that MDM2 E3 activity is stimulated by intramolecular interaction between the RING and acidic domains. Here, we show that in the mutant p53-MDM2 complex, the mutant p53 core domain binds to the MDM2 acidic domain with significantly higher avidity than wild-type p53. The mutant p53-MDM2 complex is deficient in catalyzing ubiquitin release from the activated E2 conjugating enzyme. An MDM2 construct with extra copies of the acidic domain is resistant to inhibition by mutant p53 and efficiently promotes mutant p53 ubiquitination and degradation. The results suggest that mutant p53 interferes with the intramolecular autoactivation mechanism of MDM2, contributing to reduced ubiquitination and increased accumulation in tumor cells.

scholarly journals Mutant p53 Disrupts MCF-10A Cell Polarity in Three-dimensional Culture via Epithelial-to-mesenchymal Transitions

2011 ◽  
Vol 286 (18) ◽  
pp. 16218-16228 ◽  
Author(s):  
Yanhong Zhang ◽  
Wensheng Yan ◽  
Xinbin Chen
Keyword(s):  
Cell Polarity ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Three Dimensional ◽  
Mutant P53 ◽  
Wild Type ◽  
Gain Of Function ◽  
Three Dimensional Culture ◽  
Wild Type P53 ◽  
E Cadherin

Mutant p53 is not only deficient in tumor suppression but also acquires additional activity, called gain of function. Mutant p53 gain of function is recapitulated in knock-in mice that carry one null allele and one mutant allele of the p53 gene. These knock-in mice develop aggressive tumors compared with p53-null mice. Recently, we and others showed that tumor cells carrying a mutant p53 are addicted to the mutant for cell survival and resistance to DNA damage. To further define mutant p53 gain of function, we used the MCF-10A three-dimensional model of mammary morphogenesis. MCF-10A cells in three-dimensional culture undergo a series of morphological changes and form polarized and growth-arrested spheroids with hollow lumen, which resembles normal glandular architectures in vivo. Here, we found that endogenous wild-type p53 in MCF-10A cells was not required for acinus formation, but knockdown of endogenous wild-type p53 (p53-KD) led to partial clearance of cells in the lumen due to decreased apoptosis. Consistent with this, p53-KD altered expression patterns of the cell adhesion molecule E-cadherin, the cytoskeletal marker β-catenin, and the extracellular matrix protein laminin V. We also found that ectopic expression of the mutant G245S led to a phenotype similar to p53-KD, whereas a combination of ectopic expression of siRNA-resistant G245S with p53-KD led to a less cleared lumen. In contrast, ectopic expression of mutant R248W, R175H, and R273H disrupted normal acinus architectures with filled lumen and led to formation of irregular and multiacinus structures regardless of p53-KD. In addition, these mutants altered normal expression patterns and/or levels of E-cadherin, β-catenin, laminin V, and tight junction marker ZO-1. Furthermore, epithelial-to-mesenchymal transitions (EMT) markers, Snail, Slug, and Twist, were highly induced by mutant p53 and/or p53-KD. Together, we postulate that EMT represents a mutant p53 gain of function and mutant p53 alters cell polarity via EMT.

scholarly journals Germline gain-of-function mutation of STAT1 rescued by somatic mosaicism in immune dysregulation-polyendocrinopathy-enteropathy-X-linked-like disorder

2020 ◽  
Vol 145 (3) ◽  
pp. 1017-1021 ◽  
Author(s):  
Jeong Seok Lee ◽  
Yohan An ◽  
Christopher J. Yoon ◽  
Jeong Yeon Kim ◽  
Kyung Hwan Kim ◽  
...  
Keyword(s):  
Somatic Mosaicism ◽  
Immune Dysregulation ◽  
Gain Of Function

scholarly journals Application of a Biologically Contained Reporter System To Study Gain-of-Function H5N1 Influenza A Viruses with Pandemic Potential

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Eva E. Spieler ◽  
Eva Moritz ◽  
Silke Stertz ◽  
Benjamin G. Hale
Keyword(s):  
Viral Genome ◽  
Influenza A ◽  
Risk Mitigation ◽  
Genetically Modified ◽  
Influenza Viruses ◽  
Mitigation Strategies ◽  
Wild Type ◽  
Gain Of Function ◽  
Ha Gene ◽  
Risk Mitigation Strategies

ABSTRACT Natural adaptation of an antigenically novel avian influenza A virus (IAV) to be transmitted efficiently in humans has the potential to trigger a devastating pandemic. Understanding viral genetic determinants underlying adaptation is therefore critical for pandemic preparedness, as the knowledge gained enhances surveillance and eradication efforts, prepandemic vaccine design, and efficacy assessment of antivirals. However, this work has risks, as making gain-of-function substitutions in fully infectious IAVs may create a pathogen with pandemic potential. Thus, such experiments must be tightly controlled through physical and biological risk mitigation strategies. Here, we applied a previously described biological containment system for IAVs to a 2009 pandemic H1N1 strain and a highly pathogenic H5N1 strain. The system relies on deletion of the essential viral hemagglutinin (HA) gene, which is instead provided in trans, thereby restricting multicycle virus replication to genetically modified HA-complementing cells. In place of HA, a Renilla luciferase gene is inserted within the viral genome, and a live-cell luciferase substrate allows real-time quantitative monitoring of viral replication kinetics with a high dynamic range. We demonstrate that biologically contained IAV-like particles exhibit wild-type sensitivities to approved antivirals, including oseltamivir, zanamivir, and baloxavir. Furthermore, the inability of these IAV-like particles to genetically acquire the host-encoded HA allowed us to introduce gain-of-function substitutions in the H5 HA gene that promote mammalian transmissibility. Biologically contained “transmissible” H5N1 IAV-like particles exhibited wild-type sensitivities to approved antivirals, to the fusion inhibitor S20, and to neutralization by existing H5 monoclonal and polyclonal sera. This work represents a proof of principle that biologically contained IAV systems can be used to safely conduct selected gain-of-function experiments. IMPORTANCE Understanding how animal influenza viruses can adapt to spread in humans is critical to prepare for, and prevent, new pandemics. However, working safely with pathogens that have pandemic potential requires tight regulation and the use of high-level physical and biological risk mitigation strategies to stop accidental loss of containment. Here, we used a biological containment system for influenza viruses to study strains with pandemic potential. The system relies on deletion of the essential HA gene from the viral genome and its provision by a genetically modified cell line, to which virus propagation is therefore restricted. We show that this method permits safe handling of these pathogens, including gain-of-function variants, without the risk of generating fully infectious viruses. Furthermore, we demonstrate that this system can be used to assess virus sensitivity to both approved and experimental drugs, as well as the antigenic profile of viruses, important considerations for evaluating prepandemic vaccine and antiviral strategies.

scholarly journals Re-evaluation of the nor mutation and the role of the NAC-NOR transcription factor in tomato fruit ripening

2020 ◽  
Vol 71 (12) ◽  
pp. 3560-3574 ◽  
Author(s):  
Ying Gao ◽  
Wei Wei ◽  
Zhongqi Fan ◽  
Xiaodan Zhao ◽  
Yiping Zhang ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Tomato Fruit ◽  
Pectate Lyase ◽  
Ethylene Biosynthesis ◽  
Fruit Softening ◽  
Wild Type ◽  
Gain Of Function ◽  
Carotenoid Accumulation ◽  
Acid Protein ◽  
Tomato Fruit Ripening

Abstract The tomato non-ripening (nor) mutant generates a truncated 186-amino-acid protein (NOR186) and has been demonstrated previously to be a gain-of-function mutant. Here, we provide more evidence to support this view and answer the open question of whether the NAC-NOR gene is important in fruit ripening. Overexpression of NAC-NOR in the nor mutant did not restore the full ripening phenotype. Further analysis showed that the truncated NOR186 protein is located in the nucleus and binds to but does not activate the promoters of 1-aminocyclopropane-1-carboxylic acid synthase2 (SlACS2), geranylgeranyl diphosphate synthase2 (SlGgpps2), and pectate lyase (SlPL), which are involved in ethylene biosynthesis, carotenoid accumulation, and fruit softening, respectively. The activation of the promoters by the wild-type NOR protein can be inhibited by the mutant NOR186 protein. On the other hand, ethylene synthesis, carotenoid accumulation, and fruit softening were significantly inhibited in CR-NOR (CRISPR/Cas9-edited NAC-NOR) fruit compared with the wild-type, but much less severely affected than in the nor mutant, while they were accelerated in OE-NOR (overexpressed NAC-NOR) fruit. These data further indicated that nor is a gain-of-function mutation and NAC-NOR plays a significant role in ripening of wild-type fruit.

scholarly journals A Gain-of-Function Mutation in Gating of Corynebacterium glutamicum NCgl1221 Causes Constitutive Glutamate Secretion

2012 ◽  
Vol 78 (15) ◽  
pp. 5432-5434 ◽  
Author(s):  
Yoshitaka Nakayama ◽  
Kenjiro Yoshimura ◽  
Hidetoshi Iida
Keyword(s):  
Patch Clamp ◽  
Corynebacterium Glutamicum ◽  
Mechanosensitive Channel ◽  
Wild Type ◽  
Gain Of Function ◽  
Content Type ◽  
Wild Type Counterpart

ABSTRACTThe A-to-V mutation at position 111 (A111V) in the mechanosensitive channel NCgl1221 (MscCG) causes constitutive glutamate secretion inCorynebacterium glutamicum. Patch clamp experiments revealed that NCgl1221 (A111V) had a significantly smaller gating threshold than the wild-type counterpart and displayed strong hysteresis, suggesting that the gain-of-function mutation in the gating of NCgl1221 leads to the oversecretion of glutamate.

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