P273 A case of agammaglobulinemia attributed to heterozygous, dominant-negative mutation in transcription factor E47

Abstract Transcription factors involved in myeloid cell differentiation are frequent targets of chromosomal translocations or point mutations in patients with acute myeloblastic leukemia (AML). Familial AML harboring a mutation of a transcription factor should provide an association with clinical features and functions of the transcription factor. Recently, two pedigrees of AML carried a germ-line mutation in the CEBPA, the gene encoding transcription factor C/EBPα. have been reported. We here present clinical and molecular features of a Japanese family in whom two members affected by AML had an identical CEBPA mutation. Father had received the diagnosis of AML M2 in 1988 at the age of 39 years. His blast cells contained Auer rods and aberrantly expressed CD7 antigen. Following a relapse, he received autologous stem cell transplantation, after which he has been in a lasting complete remission (CR). His son was diagnosed to have M2Eo in 2004 at the age of 26 years. His marrow showed blasts including Auer rods and 6.8% eosinophils. He has achieved a continuous CR. Bone marrow cells at the time of diagnosis in both patients showed a 4-base pair insertion in the CEBPA (350_351insCTAC). The corresponding protein is predicted to terminate prematurely at codon 107 (I68fsX107). Therefore, this heterozygous mutation causes truncation of the 42-kD C/EBPα protein and overproduction of a 30-kD isoform, which functions in a dominant negative fashion, causing a decrease in C/EBPα activities. Peripheral blood cells obtained during CR in both patients also had the same mutation. Interestingly, the germ-line mutation identified in the affected individuals we present is almost identical to those in the familial AMLs carrying a C/EBPα mutation, 212delC or 217insC. N-terminal C/EBPα mutations in sporadic AML patients are associated with M1/M2, presence of Auer rods, CD7 expression, normal karyotype, and favorable prognosis. Familial AMLs with a C/EBPα mutation demonstrate links of these unique features to a dominant negative C/EBPα mutation. Although the mechanism underlying the development of AML is yet unclear, carriers of the CEBPA mutation appear to have a large population of undifferentiated myeloid cells associated with an increased risk of a second genetic hit, leading to AML over a long latency.

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Mutation P291fsinsC in the transcription factor hepatocyte nuclear factor-1alpha is dominant negative

Diabetes ◽

10.2337/diabetes.47.8.1231 ◽

1998 ◽

Vol 47 (8) ◽

pp. 1231-1235 ◽

Cited By ~ 19

Author(s):

K. Yamagata ◽

Q. Yang ◽

K. Yamamoto ◽

H. Iwahashi ◽

J. Miyagawa ◽

...

Keyword(s):

Transcription Factor ◽

Dominant Negative ◽

Nuclear Factor ◽

Hepatocyte Nuclear Factor

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The Role of Alcohol, LPS Toxicity, and ALDH2 in Dental Bony Defects

Biomolecules ◽

10.3390/biom11050651 ◽

2021 ◽

Vol 11 (5) ◽

pp. 651

Author(s):

Hsiao-Cheng Tsai ◽

Che-Hong Chen ◽

Daria Mochly-Rosen ◽

Yi-Chen Ethan Li ◽

Min-Huey Chen

Keyword(s):

Bone Loss ◽

Bacterial Infection ◽

Bone Regeneration ◽

Alcohol Drinking ◽

Bacterial Species ◽

Dominant Negative ◽

Enzyme Inactivation ◽

Wild Type ◽

Micro Computed Tomography ◽

Dominant Negative Mutation

It is estimated that 560 million people carry an East Asian-specific ALDH2*2 dominant-negative mutation which leads to enzyme inactivation. This common ALDH2 polymorphism has a significant association with osteoporosis. We hypothesized that the ALDH2*2 mutation in conjunction with periodontal Porphyromonas gingivalis bacterial infection and alcohol drinking had an inhibitory effect on osteoblasts and bone regeneration. We examined the prospective association of ALDH2 activity with the proliferation and mineralization potential of human osteoblasts in vitro. The ALDH2 knockdown experiments showed that the ALDH2 knockdown osteoblasts lost their proliferation and mineralization capability. To mimic dental bacterial infection, we compared the dental bony defects in wild-type mice and ALDH2*2 knockin mice after injection with purified lipopolysaccharides (LPS), derived from P. gingivalis which is a bacterial species known to cause periodontitis. Micro-computed tomography (micro-CT) scan results indicated that bone regeneration was significantly affected in the ALDH2*2 knockin mice with about 20% more dental bony defects after LPS injection than the wild-type mice. Moreover, the ALDH2*2 knockin mutant mice had decreased osteoblast growth and more dental bone loss in the upper left jaw region after LPS injection. In conclusion, these results indicated that the ALDH2*2 mutation with alcohol drinking and chronic exposure to dental bacterial-derived toxin increased the risk of dental bone loss.

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Cellular Werner Phenotypes in Mice Expressing a Putative Dominant-Negative Human WRN Gene

Genetics ◽

10.1093/genetics/154.1.357 ◽

2000 ◽

Vol 154 (1) ◽

pp. 357-362

Author(s):

Lan Wang ◽

Charles E Ogburn ◽

Carol B Ware ◽

Warren C Ladiges ◽

Hagop Youssoufian ◽

...

Keyword(s):

Mouse Model ◽

Transgenic Mice ◽

Werner Syndrome ◽

Dominant Negative ◽

Dominant Negative Mutation ◽

Fibroblast Cultures ◽

Age Related

Abstract Mutations at the Werner helicase locus (WRN) are responsible for the Werner syndrome (WS). WS patients prematurely develop an aged appearance and various age-related disorders. We have generated transgenic mice expressing human WRN with a putative dominant-negative mutation (K577M-WRN). Primary tail fibroblast cultures from K577M-WRN mice showed three characteristics of WS cells: hypersensitivity to 4-nitroquinoline-1-oxide (4NQO), reduced replicative potential, and reduced expression of the endogenous WRN protein. These data suggest that K577M-WRN mice may provide a novel mouse model for the WS.

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The new kid on the block: A dominant‐negative mutation of phototropin1 enhances carotenoid content in tomato fruits

The Plant Journal ◽

10.1111/tpj.15206 ◽

2021 ◽

Author(s):

Himabindu Vasuki Kilambi ◽

Alekhya Dindu ◽

Kapil Sharma ◽

Narasimha Rao Nizampatnam ◽

Neha Gupta ◽

...

Keyword(s):

Dominant Negative ◽

Carotenoid Content ◽

Tomato Fruits ◽

Dominant Negative Mutation

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Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

Molecular and Cellular Biology ◽

10.1128/mcb.16.4.1842 ◽

1996 ◽

Vol 16 (4) ◽

pp. 1842-1850 ◽

Cited By ~ 193

Author(s):

G Baier-Bitterlich ◽

F Uberall ◽

B Bauer ◽

F Fresser ◽

H Wachter ◽

...

Keyword(s):

Transcription Factor ◽

Transcriptional Activation ◽

Dominant Negative ◽

Dominant Negative Mutant ◽

Kinase C ◽

Pkc Isoforms ◽

Pkc Alpha ◽

Transcriptional Complex ◽

Induced Signal ◽

Transcription Factor Complex

T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-O K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-enRasS17N completely inhibited in the PKC-O A148E-induced signal, identifying PKC-theta as a specific constituent upstream of or parallel to Ras in the signaling cascade leading to AP transcriptional activation.

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Hyper-IgM syndrome with putative dominant negative mutation in activation-induced cytidine deaminase

Journal of Allergy and Clinical Immunology ◽

10.1016/s0091-6749(03)01860-8 ◽

2003 ◽

Vol 112 (4) ◽

pp. 755-760 ◽

Cited By ~ 21

Author(s):

Y Kasahara

Keyword(s):

Cytidine Deaminase ◽

Dominant Negative ◽

Dominant Negative Mutation ◽

Hyper Igm Syndrome ◽

Activation Induced Cytidine Deaminase ◽

Hyper Igm

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CHOP Enhancement of Gene Transcription by Interactions with Jun/Fos AP-1 Complex Proteins

Molecular and Cellular Biology ◽

10.1128/mcb.19.11.7589 ◽

1999 ◽

Vol 19 (11) ◽

pp. 7589-7599 ◽

Cited By ~ 95

Author(s):

Mariano Ubeda ◽

Mario Vallejo ◽

Joel F. Habener

Keyword(s):

Transcription Factor ◽

Gene Transcription ◽

Stress Responses ◽

Leucine Zipper ◽

Target Genes ◽

Cellular Stress ◽

Dominant Negative ◽

Dimerization Domain ◽

Mobility Shift

ABSTRACT The transcription factor CHOP (C/EBP homologous protein 10) is a bZIP protein induced by a variety of stimuli that evoke cellular stress responses and has been shown to arrest cell growth and to promote programmed cell death. CHOP cannot form homodimers but forms stable heterodimers with the C/EBP family of activating transcription factors. Although initially characterized as a dominant negative inhibitor of C/EBPs in the activation of gene transcription, CHOP-C/EBP can activate certain target genes. Here we show that CHOP interacts with members of the immediate-early response, growth-promoting AP-1 transcription factor family, JunD, c-Jun, and c-Fos, to activate promoter elements in the somatostatin, JunD, and collagenase genes. The leucine zipper dimerization domain is required for interactions with AP-1 proteins and transactivation of transcription. Analyses by electrophoretic mobility shift assays and by an in vivo mammalian two-hybrid system for protein-protein interactions indicate that CHOP interacts with AP-1 proteins inside cells and suggest that it is recruited to the AP-1 complex by a tethering mechanism rather than by direct binding of DNA. Thus, CHOP not only is a negative or a positive regulator of C/EBP target genes but also, when tethered to AP-1 factors, can activate AP-1 target genes. These findings establish the existence of a new mechanism by which CHOP regulates gene expression when cells are exposed to cellular stress.

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Suppressor Mutations Bypass the Requirement of fluG for Asexual Sporulation and Sterigmatocystin Production in Aspergillus nidulans

Genetics ◽

10.1093/genetics/165.3.1083 ◽

2003 ◽

Vol 165 (3) ◽

pp. 1083-1093

Author(s):

Jeong-Ah Seo ◽

Yajun Guan ◽

Jae-Hyuk Yu

Keyword(s):

Aspergillus Nidulans ◽

Molecular Mechanisms ◽

Dominant Negative ◽

Wild Type ◽

Dominant Mutation ◽

Site Mutation ◽

Asexual Sporulation ◽

Dominant Negative Mutation ◽

Suppressor Mutations ◽

Early Developmental

Abstract Asexual sporulation (conidiation) in the filamentous fungus Aspergillus nidulans requires the early developmental activator fluG. Loss of fluG results in the blockage of both conidiation and production of the mycotoxin sterigmatocystin (ST). To investigate molecular mechanisms of fluG-dependent developmental activation, 40 suppressors of fluG (SFGs) that conidiate without fluG have been isolated and characterized. Genetic analyses showed that an individual suppression is caused by a single second-site mutation, and that all sfg mutations but one are recessive. Pairwise meiotic crosses grouped mutations to four loci, 31 of them to sfgA, 6 of them to sfgB, and 1 each to sfgC and sfgD, respectively. The only dominant mutation, sfgA38, also mapped to the sfgA locus, suggesting a dominant negative mutation. Thirteen sfgA and 1 sfgC mutants elaborated conidiophores in liquid submerged culture, indicating that loss of either of these gene functions not only bypasses fluG function but also results in hyperactive conidiation. While sfg mutants show varying levels of restored conidiation, all recovered the ability to produce ST at near wild-type levels. The fact that at least four loci are defined by recessive sfg mutations indicates that multiple genes negatively regulate conidiation downstream of fluG and that the activity of fluG is required to remove such repressive effects.

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Cdk5 mediates changes in morphology and promotes apoptosis of astrocytoma cells in response to heat shock

Journal of Cell Science ◽

10.1242/jcs.114.6.1145 ◽

2001 ◽

Vol 114 (6) ◽

pp. 1145-1153 ◽

Cited By ~ 1

Author(s):

C. Gao ◽

S. Negash ◽

H.S. Wang ◽

D. Ledee ◽

H. Guo ◽

...

Keyword(s):

Heat Shock ◽

Cell Line ◽

Fluorescent Protein ◽

Morphological Changes ◽

Normal Growth ◽

Dominant Negative ◽

Specific Expression ◽

Cell Matrix ◽

Dominant Negative Mutation ◽

U373 Cells

The cyclin-dependent kinase member, Cdk5, is expressed in a variety of cell types, but neuron-specific expression of its activator, p35, is thought to limit its activity to neurons. Here we demonstrate that both Cdk5 and p35 are expressed in the human astrocytoma cell line, U373. Cdk5 and p35 are present in the detergent-insoluble cytoskeletal fraction of this cell line and Cdk5 localizes to filopodia and vinculin-rich regions of cell-matrix contact in lamellopodia. When exposed to a 46(o)C heat shock, U373 cells change shape, lose cell-matrix contacts and show increased levels of apoptosis. To test whether Cdk5 activation might play a role in these events, U373 cells were stably transfected with histidine-tagged or green fluorescent protein-tagged constructs of Cdk5 or a dominant negative mutation, Cdk5T33. Under normal growth conditions, growth characteristics of the stably transfected lines were indistinguishable from untransfected U373 cells and Cdk5 localization was not changed. However, when subjected to heat shock, cells stably transfected with Cdk5-T33 remained flattened, showed little loss of cell-matrix adhesion, and exhibited significantly lower levels of apoptosis. In contrast, cells that overexpressed wild-type Cdk5 showed morphological changes similar to those seen in untransfected U373 cells in response to heat shock and had significantly higher levels of apoptosis. Heat-shocked cells showed changes in p35 mobility and stability of the Cdk5/p35 complex consistent with endogenous Cdk5 activity. Together these findings suggest that endogenous Cdk5 activity may play a key role in regulating morphology, attachment, and apoptosis in U373 cells, and raise the possibility that Cdk5 may be a general regulator of cytoskeletal organization and cell adhesion in both neuronal and non-neuronal cells.

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