A mouse model of Alagille syndrome:Notch2as a genetic modifier ofJag1haploinsufficiency

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 1075-1082 ◽  
Author(s):  
Brent McCright ◽  
Julie Lozier ◽  
Thomas Gridley
Keyword(s):  
Mouse Model ◽  
Kidney Development ◽  
Genetic Modifier ◽  
Phenotypic Expression ◽  
Notch Pathway ◽  
Alagille Syndrome ◽  
Notch Signaling Pathway ◽  
Epithelial Morphogenesis ◽  
Null Alleles ◽  
Developmental Abnormalities

Alagille syndrome is a human autosomal dominant developmental disorder characterized by liver, heart, eye, skeletal, craniofacial and kidney abnormalities. Alagille syndrome is caused by mutations in the Jagged 1 (JAG1) gene, which encodes a ligand for Notch family receptors. The majority of JAG1 mutations seen in Alagille syndrome patients are null alleles, suggesting JAG1 haploinsufficiency as a primary cause of this disorder. Mice homozygous for a Jag1 null mutation die during embryogenesis and Jag1/+ heterozygous mice exhibit eye defects but do not exhibit other phenotypes characteristic of Alagille syndrome patients (Xue, Y., Gao, X., Lindsell, C. E., Norton, C. R., Chang, B., Hicks, C., Gendron-Maguire, M., Rand, E. B., Weinmaster, G. and Gridley, T. (1999) Hum. Mol. Genet.8, 723-730). Here we report that mice doubly heterozygous for the Jag1 null allele and a Notch2 hypomorphic allele exhibit developmental abnormalities characteristic of Alagille syndrome. Double heterozygous mice exhibit jaundice, growth retardation, impaired differentiation of intrahepatic bile ducts and defects in heart, eye and kidney development. The defects in bile duct epithelial cell differentiation and morphogenesis in the double heterozygous mice are similar to defects in epithelial morphogenesis of Notch pathway mutants in Drosophila, suggesting that a role for the Notch signaling pathway in regulating epithelial morphogenesis has been conserved between insects and mammals. This work also demonstrates that the Notch2 and Jag1 mutations interact to create a more representative mouse model of Alagille syndrome and provides a possible explanation of the variable phenotypic expression observed in Alagille syndrome patients.

scholarly journals A Genetic Screen for Novel Components of the Notch Signaling Pathway During Drosophila Bristle Development

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 211-220 ◽  
Author(s):  
Masahiro J Go ◽  
Spyros Artavanis-Tsakonas
Keyword(s):  
Notch Signaling ◽  
Cell Fate ◽  
Genetic Modifier ◽  
Notch Pathway ◽  
Central Element ◽  
Notch Signaling Pathway ◽  
Notch Receptor ◽  
Loss Of Function ◽  
Gain Of Function ◽  
Signaling Mechanism

Abstract The Notch receptor is the central element in a cell signaling mechanism controlling a broad spectrum of cell fate choices. Genetic modifier screens in Drosophila and subsequent molecular studies have identified several Notch pathway components, but the biochemical nature of signaling is still elusive. Here, we report the results of a genetic modifier screen of the bristle phenotype of a gain-of-function Notch allele, Abruptex16. Abruptex mutations interfere with lateral inhibition/specification events that control the segregation of epidermal and sensory organ precursor lineages, thus inhibiting bristle formation. Mutations that reduce Notch signaling suppress this phenotype. This screen of approximately 50,000 flies led to the identification of a small number of dominant suppressors in seven complementation groups. These include known components in the pathway, Notch, mastermind, Delta, and Hairless, as well as two novel mutations. The first, A122, appears to interact with Notch only during bristle development. The other, M285, displays extensive genetic interactions with the Notch pathway elements and appears, in general, capable of suppressing Notch gain-of-function phenotypes while enhancing Notch loss-of-function phenotypes, suggesting that it plays an important role in Notch signaling.

Double resin casting micro computed tomography (CT) reveals biliary and vascular pathology in tandem in a mouse model for alagille syndrome

2020 ◽  
Vol 73 ◽  
pp. S43
Author(s):  
Simona Hankeova ◽  
Jakub Salplachta ◽  
Tomas Zikmund ◽  
Michaela Kavkova ◽  
Noémi K.M. Van Hul ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Mouse Model ◽  
Alagille Syndrome ◽  
Vascular Pathology ◽  
Micro Computed Tomography

scholarly journals The Heat Sensing Trpv1 Receptor Is Not a Viable Anticonvulsant Drug Target in the Scn1a+/− Mouse Model of Dravet Syndrome

2021 ◽  
Vol 12 ◽  
Author(s):  
Vaishali Satpute Janve ◽  
Lyndsey L. Anderson ◽  
Dilara Bahceci ◽  
Nicole A. Hawkins ◽  
Jennifer A. Kearney ◽  
...  
Keyword(s):  
Mouse Model ◽  
Drug Target ◽  
Genetic Modifier ◽  
Anticonvulsant Drug ◽  
Dravet Syndrome ◽  
Seizure Threshold ◽  
Drug Resistant ◽  
Spontaneous Seizures ◽  
Temperature Thresholds ◽  
Seizure Models

Cannabidiol has been approved for the treatment of drug-resistant childhood epilepsies including Dravet syndrome (DS). Although the mechanism of anticonvulsant action of cannabidiol is unknown, emerging data suggests involvement of the transient receptor potential cation channel subfamily V member 1 (Trpv1). Pharmacological and genetic studies in conventional seizure models suggest Trpv1 is a novel anticonvulsant target. However, whether targeting Trpv1 is anticonvulsant in animal models of drug-resistant epilepsies is not known. Thus, we examined whether Trpv1 affects the epilepsy phenotype of the F1.Scn1a+/− mouse model of DS. We found that cortical Trpv1 mRNA expression was increased in seizure susceptible F1.Scn1a+/− mice with a hybrid genetic background compared to seizure resistant 129.Scn1a+/− mice isogenic on 129S6/SvEvTac background, suggesting Trpv1 could be a genetic modifier. Previous studies show functional loss of Trpv1 is anticonvulsant. However, Trpv1 selective antagonist SB-705498 did not affect hyperthermia-induced seizure threshold, frequency of spontaneous seizures or survival of F1.Scn1a+/− mice. Surprisingly, Trpv1 deletion had both pro- and anti-seizure effects. Trpv1 deletion did not affect hyperthermia-induced seizure temperature thresholds of F1.Scn1a+/−; Trpv1+/− at P14-16 but was proconvulsant at P18 as it reduced seizure temperature thresholds. Conversely, Trpv1 deletion did not alter the frequency of spontaneous seizures but reduced their severity. These results suggest that Trpv1 is a modest genetic modifier of spontaneous seizure severity in the F1.Scn1a+/− model of DS. However, the opposing pro- and anti-seizure effects of Trpv1 deletion and the lack of effects of Trpv1 inhibition suggest that Trpv1 is unlikely a viable anticonvulsant drug target in DS.

scholarly journals Epidermoid cyst in a patient with Alagille syndrome: Coincidence or connection?

2020 ◽  
Vol 11 ◽  
pp. 432
Author(s):  
Akhil Surapaneni ◽  
John Kuo ◽  
Min Wang ◽  
Ramsey Ashour
Keyword(s):  
Notch Signaling ◽  
Signaling Pathway ◽  
Epidermoid Cyst ◽  
Alagille Syndrome ◽  
Notch Signaling Pathway ◽  
Syndrome Patient ◽  
Benign Lesions ◽  
Genetic Syndrome ◽  
Epidermoid Cysts

Background: Alagille syndrome is a rare genetic syndrome, which arises due to defects in the Notch signaling pathway, resulting in liver, cardiopulmonary, renal, skeletal, and ophthalmologic problems, among others. Epidermoid cysts are rare congenital benign lesions that develop from ectopic ectodermal cell rests formed during neurulation. Case Description: A 24-year-old Alagille syndrome patient presented with hearing loss and was found to have a sizable posterior fossa mass. He underwent craniotomy for uneventful resection of the lesion, which was found to be an epidermoid cyst. Conclusion: While our case may represent a coincidental occurrence of two pathologies presenting together, given that epidermoid cysts arise from aberrant neurulation, and in light of the crucial role of the Notch signaling pathway both in normal neurogenesis and in the pathogenesis of Alagille syndrome, we hypothesize a possible association between these entities.

scholarly journals ZFP57 dictates allelic expression switch of target imprinted genes

2021 ◽  
Vol 118 (5) ◽  
pp. e2005377118
Author(s):  
Weijun Jiang ◽  
Jiajia Shi ◽  
Jingjie Zhao ◽  
Qiu Wang ◽  
Dan Cong ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Notch Signaling ◽  
Notch Pathway ◽  
Notch Signaling Pathway ◽  
Mouse Embryos ◽  
The Other ◽  
Allelic Expression ◽  
Monoallelic Expression ◽  
Imprinted Genes ◽  
Parent Of Origin

ZFP57 is a master regulator of genomic imprinting. It has both maternal and zygotic functions that are partially redundant in maintaining DNA methylation at some imprinting control regions (ICRs). In this study, we found that DNA methylation was lost at most known ICRs in Zfp57 mutant embryos. Furthermore, loss of ZFP57 caused loss of parent-of-origin–dependent monoallelic expression of the target imprinted genes. The allelic expression switch occurred in the ZFP57 target imprinted genes upon loss of differential DNA methylation at the ICRs in Zfp57 mutant embryos. Specifically, upon loss of ZFP57, the alleles of the imprinted genes located on the same chromosome with the originally methylated ICR switched their expression to mimic their counterparts on the other chromosome with unmethylated ICR. Consistent with our previous study, ZFP57 could regulate the NOTCH signaling pathway in mouse embryos by impacting allelic expression of a few regulators in the NOTCH pathway. In addition, the imprinted Dlk1 gene that has been implicated in the NOTCH pathway was significantly down-regulated in Zfp57 mutant embryos. Our allelic expression switch models apply to the examined target imprinted genes controlled by either maternally or paternally methylated ICRs. Our results support the view that ZFP57 controls imprinted expression of its target imprinted genes primarily through maintaining differential DNA methylation at the ICRs.

scholarly journals The correlation between the granulocyte colony-stimulating factor and the Notch signaling pathway in ischemic brain injury

2021 ◽  
Author(s):  
Ning Xie ◽  
Qin Huang ◽  
Jingting Han ◽  
Wenyuan Xu
Keyword(s):  
Notch Pathway ◽  
Glucose Deprivation ◽  
Notch Signaling Pathway ◽  
Oxygen Glucose Deprivation ◽  
Control Group ◽  
Ischemic Brain Injury ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Ischemic Brain ◽  
Stimulating Factor

IntroductionThis study aims to determine the relationship between the granulocyte colony-stimulating factor (G-CSF) and the Notch signaling pathway in ischemic brain injury.Material and methodsPC-12 cells were treated with the nerve growth factor (NGF) to induce neuronal differentiation then divided into seven groups: 1) no treatment (control); 2) oxygen-glucose deprivation (OGD) model; 3) overexpressed G-CSF + OGD model; 4) transfected empty vector (negative control; NC) + OGD model; 5) overexpressed G-CSF + γ-secretase inhibitor MW167 + OGD model; 6) MW167 + OGD model; and 7) NC + MW167 + OGD model. The cells were analyzed using immunohistochemistry and apoptosis and CCK8 assays. The expression of the related molecules in the Notch pathway was detected using the Western blotting and quantitative PCR (Q-PCR).ResultsMost PC-12 cells were neuron-specific enolase (NSE)-positive after the NGF treatment. When compared with the control group, the MW167 + OGD and NC + MW167 + OGD groups had the lowest optical density (OD) values, followed by the OGD, NC + OGD and the G-CSF + MW167+ OGD groups. The G-CSF + OGD group had the highest OD value. Concerning apoptosis detection, the control group had the lowest apoptosis rate. The highest apoptosis rates were found in the MW167 + OGD, the OGD, and then the G-CSF + OGD groups.ConclusionsThe blocking of the Notch pathway can attenuate the G-CSF effects, whereas the G-CSF overexpression can activate the Notch pathway to resist the effects of oxygen-glucose deprivation.

scholarly journals Wilms' Tumor Suppressor GeneWT1

2000 ◽  
Vol 11 (suppl 2) ◽  
pp. S106-S115 ◽  
Author(s):  
CHRISTIAN MROWKA ◽  
ANDREAS SCHEDL
Keyword(s):  
Tumor Suppressor ◽  
Rna Editing ◽  
Kidney Development ◽  
Wilms Tumor ◽  
Suppressor Gene ◽  
Structural Features ◽  
Genomic Locus ◽  
Developmental Abnormalities ◽  
Complex Process

Abstract.Normal development of the kidney is a highly complex process that requires precise orchestration of proliferation, differentiation, and apoptosis. In the past few years, a number of genes that regulate these processes, and hence play pivotal roles in kidney development, have been identified. The Wilms' tumor suppressor geneWT1has been shown to be one of these essential regulators of kidney development, and mutations in this gene result in the formation of tumors and developmental abnormalities such as the Denys-Drash and Frasier syndromes. A fascinating aspect of theWT1gene is the multitude of isoforms produced from its genomic locus. In this review, our current understanding of the structural features ofWT1, how they modulate the transcriptional and post-transcriptional activities of the protein, and how mutations affecting individual isoforms can lead to diseased kidneys is summarized. In addition, results from transgenic experiments, which have yielded important findings regarding the function of WT1in vivo, are discussed. Finally, data on the unusual feature of RNA editing ofWT1transcripts are presented, and the relevance of RNA editing for the normal functioning of the WT1 protein in the kidney is discussed.

Hairy/E(spl)-related(Her) genes are central components of the segmentation oscillator and display redundancy with the Delta/Notch signaling pathway in the formation of anterior segmental boundaries in the zebrafish

Development ◽  
2002 ◽  
Vol 129 (12) ◽  
pp. 2929-2946 ◽  
Author(s):  
Andrew C. Oates ◽  
Robert K. Ho
Keyword(s):  
Notch Signaling ◽  
Signaling Pathway ◽  
Notch Pathway ◽  
Notch Signaling Pathway ◽  
Central Component ◽  
Mutant Genotype ◽  
Her Family ◽  
Somite Formation ◽  
Anterior Segments ◽  
Her Genes

We have examined the expression of a Hairy/E(spl)-related (Her) gene, her7, in the zebrafish and show that its expression in the PSM cycles similarly to her1 and deltaC. A decrease in her7 function generated by antisense oligonucleotides disrupts somite formation in the posterior trunk and tail, and disrupts the dynamic expression domains of her1 and deltaC, suggesting that her7 plays a role in coordinating the oscillations of neighboring cells in the presomitic mesoderm. This phenotype is reminiscent of zebrafish segmentation mutants with lesions in genes of the Delta/Notch signaling pathway, which also show a disruption of cyclic her7 expression. The interaction of HER genes with the Delta/Notch signaling system was investigated by introducing a loss of her7 function into mutant backgrounds. This leads to segmental defects more anterior than in either condition alone. Combining a decrease of her7 function with reduction of her1 function results in an enhanced phenotype that affects all the anterior segments, indicating that Her functions in the anterior segments are also partially redundant. In these animals, gene expression does not cycle at any time, suggesting that a complete loss of oscillator function had been achieved. Consistent with this, combining a reduction of her7 and her1 function with a Delta/Notch mutant genotype does not worsen the phenotype further. Thus, our results identify members of the Her family of transcription factors that together behave as a central component of the oscillator, and not as an output. This indicates, therefore, that the function of the segmentation oscillator is restricted to the positioning of segmental boundaries. Furthermore, our data suggest that redundancy between Her genes and genes of the Delta/Notch pathway is in part responsible for the robust formation of anterior somites in vertebrates.

The Notch signalling pathway and breast cancer: The importance of balance and cellular self-control.

2019 ◽  
Vol 14 ◽  
Author(s):  
Germán Saucedo-Correa ◽  
Alejandro Bravo-Patiño ◽  
Rosa Elvira Núñez-Anita ◽  
Javier Oviedo-Boyso ◽  
Juan José Valdez-Alarcón ◽  
...  
Keyword(s):  
Notch Signaling ◽  
Signaling Pathway ◽  
Cross Talk ◽  
Transcriptional Activation ◽  
Notch Pathway ◽  
Notch Signaling Pathway ◽  
Self Control ◽  
Design Strategies ◽  
Notch Intracellular Domain ◽  
The Cross

Notch is a cell-signaling pathway that is highly conserved in all metazoans and is responsible for cell differentiation and cross-talk communication with other signaling pathways such as WNT and Hh. In most cancers, the Notch signaling pathway is altered, causing atypical activity of vital processes such as cell cycle, differentiation and apoptosis, leading the cell to a carcinogenic state. Currently, the Notch signaling pathway has taken a special interest to design strategies in order to regulate the activity of this pathway since it is known that in the cancer molecular micro-environment the Notch pathway is over-expressed or presents an aberrant function, which, in consequence, corrupts the cross-talk communication with WNT and Hh pathways. Most of the existing strategies are focused on the systematic and whole inhibition of Notch pathway at the membrane level by the use of γ-secretases inhibitors. There are few strategies that act at the nuclear level inhibiting the activity of the transcriptional activation complex composed by the Notch intracellular domain, the transcriptional factor CSL and the Mastermind co-activator. In this review, by the fact that there are not any strategy focused to revert the over expression effect caused by the Notch pathway constitutive activity, we propose that the efforts to develop new strategies against cancer should be focused to understand the complexity of the cross-talk communication between Notch, WNT and Hh pathways to neutralize the gene aberrant activity characteristic of cancer cells which are responsible for those corrupted cross-talk communication.

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