scholarly journals Mouse strains with point mutations in TAP1 and TAP2

2009 ◽  
Vol 88 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Angelo Theodoratos ◽  
Belinda Whittle ◽  
Anselm Enders ◽  
David C Tscharke ◽  
Carla M Roots ◽  
...  
Keyword(s):  
Point Mutations ◽  
Mouse Strains

scholarly journals Indirect and direct evidence for DNA double–strand breaks in hypermutating immunoglobulin genes

2001 ◽  
Vol 356 (1405) ◽  
pp. 119-125 ◽  
Author(s):  
Heinz Jacobs ◽  
Klaus Rajewsky ◽  
Yosho Fukita ◽  
Linda Bross
Keyword(s):  
Somatic Hypermutation ◽  
Gene Segment ◽  
Point Mutations ◽  
Antigen Receptor ◽  
Double Strand Breaks ◽  
Mouse Strains ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Receptor Repertoire ◽  
Igh Locus

The generation of a diverse antigen receptor repertoire is fundamental for the functionality of the adaptive immune system. While the V(D)J recombination process that generates the primary antigen receptor repertoire is understood in great detail, it is still unclear by which mechanism immunoglobulin (Ig) genes are further diversified by somatic hypermutation. Using mouse strains that carry a non–functional, predefined V H D H J H gene segment in their IgH locus we demonstrate DNA double–strand breaks (DSBs) in and around V H D H J H in B cells undergoing somatic hypermutation. The generation of these DSBs depends on transcriptional activity, and their distribution along the V H D H J H segment parallels that of point mutations in the hypermutation domain. Furthermore, similar to hot spots of somatic hypermutation, 50–60% of all DSBs occur preferentially at RGYW motifs. DSBs may transiently dissociate the Ig promoter from the intronic enhancer to block further transcription and to initiate an error–prone nonhomologous DSB repair pathway. In accord with this model large deletions are frequently produced, along with point mutations, in a V H D H J H segment inserted together with its promoter into the IgH locus in inverted orientation. Our data suggest that DSBs are reaction intermediates of the mechanism underlying somatic hypermutation.

scholarly journals UNC-18 Modulates Ethanol Sensitivity in Caenorhabditis elegans

2009 ◽  
Vol 20 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Margaret E. Graham ◽  
Mark R. Edwards ◽  
Lindy Holden-Dye ◽  
Alan Morgan ◽  
Robert D. Burgoyne ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Point Mutations ◽  
Ethanol Exposure ◽  
Snare Complex ◽  
Motor Dysfunction ◽  
Mouse Strains ◽  
Ethanol Sensitivity ◽  
Ethanol Preference ◽  
Protein Receptor ◽  
Acute Ethanol

Acute ethanol exposure affects the nervous system as a stimulant at low concentrations and as a depressant at higher concentrations, eventually resulting in motor dysfunction and uncoordination. A recent genetic study of two mouse strains with varying ethanol preference indicated a correlation with a polymorphism (D216N) in the synaptic protein Munc18-1. Munc18-1 functions in exocytosis via a number of discrete interactions with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein syntaxin-1. We report that the mutation affects binding to syntaxin but not through either a closed conformation mode of interaction or through binding to the syntaxin N terminus. The D216N mutant instead has a specific impairment in binding the assembled SNARE complex. Furthermore, the mutation broadens the duration of single exocytotic events. Expression of the orthologous mutation (D214N) in the Caenorhabditis elegans UNC-18 null background generated transgenic rescues with phenotypically similar locomotion to worms rescued with the wild-type protein. Strikingly, D214N worms were strongly resistant to both stimulatory and sedative effects of acute ethanol. Analysis of an alternative Munc18-1 mutation (I133V) supported the link between reduced SNARE complex binding and ethanol resistance. We conclude that ethanol acts, at least partially, at the level of vesicle fusion and that its acute effects are ameliorated by point mutations in UNC-18.

scholarly journals HLA class II regulation and structure. Analysis with HLA-DR3 and HLA-DP point mutants.

1985 ◽  
Vol 162 (4) ◽  
pp. 1193-1207 ◽  
Author(s):  
D Pious ◽  
L Dixon ◽  
F Levine ◽  
T Cotner ◽  
R Johnson
Keyword(s):  
Cell Line ◽  
Point Mutations ◽  
Class Ii ◽  
Hla Class Ii ◽  
Mouse Strains ◽  
Parent Cell ◽  
Soluble Antigen ◽  
Mrna Levels ◽  
Site Mutation ◽  
Hla Dr3

Point mutations that affect HLA-DR structure or expression have not previously been described. In the present study, we isolated such mutants by immunoselection of an ethyl methanesulfonate-mutagenized HLA-DR3 cell line with an anti-HLA-DR3 monoclonal antibody, 16.23. To facilitate analysis, we used a parent cell line with a preexisting deletion of one haplotype encompassing DR and DQ alpha and beta. The selection yielded two sets of mutants, one with defects in DR3 structure, the other with defects in different steps leading to DR expression. Of the expression-defective mutants, one had undergone a second deletion removing the remaining DR alpha gene but no other class II genes. It had a normal abundance of DR beta mRNA but had lost binding of DR monomorphic antibodies, indicating that DR beta chains do not form noncognate dimers. A second mutant had an abnormally large DR alpha mRNA, probably resulting from a splice site mutation. Several mutants had marked reductions in DR beta mRNA levels; in two of these, the lesion appeared to be transcriptional because the reduction in DR beta mRNA was paralleled by an altered methylation pattern of one of the DR beta genes. Other expression-defective mutants had different posttranscriptional defects. Some of the mutations were similar to those that have been found in mouse strains defective in I-E expression, whereas others have no known natural counterpart. The matrix of reactivities of anti-HLA class II monomorphic antibodies with these and similar mutants allowed us to define the gene products recognized by these antibodies. A set of seven mutants were "epitope defective," that is, they expressed normal or near normal levels of HLA-DR3 but no longer bound 16.23. Unexpectedly, each of the epitope mutants had decreased DR dimer stability. These mutants should be useful in localizing the DR3 alloepitope and in elucidating its contribution as a restriction element in the presentation of soluble antigen to immune T cells.

scholarly journals FGF signaling in development beyond canonical pathways

2020 ◽  
Author(s):  
Ayan T. Ray ◽  
Pierre Mazot ◽  
J. Richard Brewer ◽  
Catarina Catela ◽  
Colin J. Dinsmore ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Adhesion ◽  
Tyrosine Kinases ◽  
Intracellular Signaling ◽  
Point Mutations ◽  
Mouse Strains ◽  
Null Mutant ◽  
Allelic Series ◽  
Adhesion Properties ◽  
Mutant Phenotypes

FGFs are key developmental regulators which engage a signal transduction cascade through receptor tyrosine kinases, typically involving ERK1/2, PI3K/AKT, and other effectors. However, it remains unknown if all FGF activities depend on kinase activity or these canonical signal transduction cascades. To address these questions, we generated allelic series of knock-in Fgfr1 and Fgfr2 mouse strains, carrying point mutations that disrupt binding of signaling effectors to the receptors, alone or in combination. We also produced a kinase dead allele of Fgfr2 which broadly phenocopies the null mutant. When interrogated in cranial neural crest cells, point mutations in either receptor revealed discrete functions for signaling pathways in specific craniofacial contexts, but failed to recapitulate the single or double null mutant phenotypes even in their most extensive combination. Furthermore, we found that together these signaling mutations abrogated the established FGF-induced signal transduction pathways, yet certain FGF functions such as cell-matrix and cell-cell adhesion remained unaffected. Our studies establish combinatorial roles of both Fgfr1 and Fgfr2 in development and identify novel kinase-dependent cell adhesion properties of FGF receptors, independent of well-established roles in intracellular signaling.

Tobacco chemical-induced mouse lung adenocarcinoma cell lines pin the prolactin orthologue proliferin as a lung tumour promoter

2019 ◽  
Vol 40 (11) ◽  
pp. 1352-1362 ◽  
Author(s):  
Nikolaos I Kanellakis ◽  
Anastasios D Giannou ◽  
Mario A A Pepe ◽  
Theodora Agalioti ◽  
Dimitra E Zazara ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Mouse Models ◽  
Cell Lines ◽  
Point Mutations ◽  
Mouse Lung ◽  
Mouse Strains ◽  
Lung Tumour ◽  
Tobacco Carcinogens

Abstract Lung adenocarcinoma (LADC) is the leading cause of cancer death worldwide. Nevertheless, syngeneic mouse models of the disease are sparse, and cell lines suitable for transplantable and immunocompetent mouse models of LADC remain unmet needs. We established multiple mouse LADC cell lines by repeatedly exposing two mouse strains (FVB, Balb/c) to the tobacco carcinogens urethane or diethylnitrosamine and by culturing out the resulting lung tumours for prolonged periods of time. Characterization of the resulting cell lines (n = 7) showed that they were immortal and phenotypically stable in vitro, and oncogenic, metastatic and lethal in vivo. The primary tumours that gave rise to the cell lines, as well as secondary tumours generated by transplantation of the cell lines, displayed typical LADC features, such as glandular architecture and mucin and thyroid transcription factor 1 expression. Moreover, these cells exhibited marked molecular similarity with human smokers’ LADC, including carcinogen-specific Kras point mutations (KrasQ61R in urethane- and KrasQ61H in diethylnitrosamine-triggered cell lines) and Trp53 deletions and displayed stemness features. Interestingly, all cell lines overexpressed proliferin, a murine prolactin orthologue, which functioned as a lung tumour promoter. Furthermore, prolactin was overexpressed and portended poor prognosis in human LADC. In conclusion, we report the first LADC cell lines derived from mice exposed to tobacco carcinogens. These cells closely resemble human LADC and provide a valuable tool for the functional investigation of the pathobiology of the disease.

Alterations in the number of motoneurons containing immunoreactive calcitonin gene-related peptide(CGRP)& choline acetyltransferase(ChAT) in the cervical spinal cord of the wobbler mouse during the development of the motoneuron disease

1995 ◽  
Vol 53 ◽  
pp. 970-971
Author(s):  
L. Vacca-Galloway ◽  
Y.Q. Zhang ◽  
P. Bose ◽  
S.H. Zhang
Keyword(s):  
Spinal Cord ◽  
Early Stage ◽  
Cervical Spinal Cord ◽  
Wild Type Mouse ◽  
Reflex Response ◽  
Mouse Strains ◽  
Behavioral Tests ◽  
Wobbler Mouse ◽  
Stage 4 ◽  
Stage 1

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.

A Novel Mutation Glyl672→Arg in Type 2A and a Homozygous Mutation in Type 2B von Willebrand Disease

1996 ◽  
Vol 76 (02) ◽  
pp. 253-257 ◽  
Author(s):  
Takeshi Hagiwara ◽  
Hiroshi Inaba ◽  
Shinichi Yoshida ◽  
Keiko Nagaizumi ◽  
Morio Arai ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Novel Mutation ◽  
Point Mutations ◽  
Japanese Patients ◽  
Von Willebrand Disease ◽  
Homozygous Mutation ◽  
Missense Mutations ◽  
Reaction Products ◽  
Type 3 ◽  
Von Willebrand

SummaryGenetic materials from 16 unrelated Japanese patients with von Willebrand disease (vWD) were analyzed for mutations. Exon 28 of the von Willebrand factor (vWF) gene, where point mutations have been found most frequent, was screened by various restriction-enzyme analyses. Six patients were observed to have abnormal restriction patterns. By sequence analyses of the polymerase chain-reaction products, we identified a homozygous R1308C missense mutation in a patient with type 2B vWD; R1597W, R1597Q, G1609R and G1672R missense mutations in five patients with type 2A; and a G1659ter nonsense mutation in a patient with type 3 vWD. The G1672R was a novel missense mutation of the carboxyl-terminal end of the A2 domain. In addition, we detected an A/C polymorphism at nucleotide 4915 with HaeIII. There was no particular linkage disequilibrium of the A/C polymorphism, either with the G/A polymorphism at nucleotide 4391 detected with Hphl or with the C/T at 4891 detected with BstEll.

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