scholarly journals P01.29 Mutant (R132H) IDH1-driven cellular transformation makes cells dependent on continued wild type IDH1 expression in a model of in vitro gliomagenesis

2017 ◽  
Vol 19 (suppl_3) ◽  
pp. iii29-iii30
Author(s):  
T. Johannessen ◽  
J. Mukherjee ◽  
M. Wood ◽  
P. Viswanath ◽  
S. Ohba ◽  
...  
Keyword(s):  
Cellular Transformation ◽  
Wild Type

scholarly journals Transformation by the Bmi-1 oncoprotein correlates with its subnuclear localization but not its transcriptional suppression activity.

1996 ◽  
Vol 16 (10) ◽  
pp. 5527-5535 ◽  
Author(s):  
K J Cohen ◽  
J S Hanna ◽  
J E Prescott ◽  
C V Dang
Keyword(s):  
Ring Finger ◽  
Cellular Transformation ◽  
Protein Product ◽  
Polycomb Group ◽  
Wild Type ◽  
Nuclear Entry ◽  
Ring Finger Domain ◽  
Subnuclear Localization ◽  
Transcriptional Suppression

The bmi-1 oncogene cooperates with c-myc in transgenic mice, resulting in accelerated lymphoma development. Altering the expression of Bmi-1 affects normal embryogenesis. The protein product of bmi-1 is homologous to certain Drosophila Polycomb group proteins that regulate homeotic gene expression through alteration of chromatin structure. Chimeric LexA-Bmi-1 protein has previously been shown to repress transcription. How Bmi-1 functions in embryogenesis and whether this relates to the ability of Bmi-1 to mediate cellular transformation is unknown. We demonstrate here that Bmi-1 is able to transform rodent fibroblasts in vitro, providing a system that has allowed us to correlate its molecular properties with its ability to transform cells. We map functional domains of Bmi-1 involved in transcriptional suppression by using the GAL4 chimeric transcriptional regulator system. Deletion analysis shows that the centrally located helix-turn-helix-turn-helix-turn (HTHTHT) motif is necessary for transcriptional suppression whereas the N-terminal RING finger domain is not required. We demonstrate that nuclear localization requires KRMK (residues 230 to 233) and that the absence of nuclear entry ablates transformation. In addition, we find that the subnuclear localization of wild-type Bmi-1 to the rim of the nucleus requires the RING finger domain and correlates with its ability to transform. Our studies with Bmi-1 deletion mutants suggest that the ability of Bmi-1 to mediate cellular transformation correlates with its unique subnuclear localization but not its transcriptional suppression activity.

scholarly journals Molecular mechanisms regulating protein kinase Czeta turnover and cellular transformation

2004 ◽  
Vol 378 (1) ◽  
pp. 83-92 ◽  
Author(s):  
J. Ann LE GOOD ◽  
David N. BRINDLEY
Keyword(s):  
Protein Kinase ◽  
Molecular Mechanisms ◽  
Cell Transformation ◽  
Specific Activity ◽  
Cellular Transformation ◽  
Wild Type ◽  
Focus Formation ◽  
Vitro Assay ◽  
Proteosomal Degradation

The regulation of protein kinase C (PKC)ζ in relation to its turnover, cell growth and transformation was investigated in Rat2 fibroblasts by over-expressing wild-type or mutant forms of PKCζ. Deletion of the pseudosubstrate site (PSS) produced the most active mutant (PKCζ Δ PSS), but mutants designed to mimic phosphorylated PKCζ had lower specific activities in an in vitro assay. The mutant lacking phosphorylation at the Thr-560 site (T560A) had similar specific activity to wild-type PKCζ. The T560A mutant also protected PKCζ against proteolysis, whereas phosphorylation at Thr-410 targeted it towards proteosomal degradation. Blocking proteosomal degradation with lactacystin caused the accumulation of full-length PKCζ Δ PSS, T410E, PKCζ Δ PSS T410/560E, PKCζ and T560A. Expressed PKCζ activity was paralleled by extracellular-regulated protein kinase activation, increased cell division, serum-independent growth and focus formation. These foci were seen for cells expressing higher PKCζ activity (PKCζ Δ PSS, PKCζ Δ PSS T410/560E and T560A mutants), but these fibroblasts did not show significant anchorage-independent growth. This work provides novel information concerning the role of the PSS and phosphorylation sites in regulating the activity and turnover of an atypical PKC and shows how this activity can induce cell transformation with respect to focus formation.

Expression of BCR-ABL Does Not Inhibit Apoptosis In Vitro, on a B Lymphoblastoid Cell Line.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4242-4242
Author(s):  
Fabiola A. Castro ◽  
Gabriela Brumatti ◽  
Gustavo P. Amarante-Mendes
Keyword(s):  
Cell Lines ◽  
Mrna Level ◽  
Philadelphia Chromosome ◽  
Ectopic Expression ◽  
Cellular Transformation ◽  
Lymphocytic Leukemia ◽  
Myelogenous Leukemia ◽  
Wild Type ◽  
Protein Levels

Abstract The bcr-abl oncogene is generated by the Philadelphia chromosome (Ph) translocation, fusing the BCR gene to the ABL gene and occurs mainly in two different forms. In chronic myelogenous leukemia (CML) a 210kDa Bcr-Abl protein is associated with proliferation and accumulation of myeloid cells and their precursors, whereas a 185kDa form is responsible for the pathogenesis of acute lymphocytic leukemia (ALL). Bcr-Abl not only induces cellular transformation but also regulates cell proliferation and confers resistance to a variety of apoptosis-inducing agents. Much attention has been focused on the development of novel therapies based on mechanistic understanding of Bcr-abl signaling in CML cells. However, we still do not fully understand how this molecule interferes with apoptotic machinery. The aim of this study was to investigate which step of the apoptotic machinery was most influenced by ectopic expression of Bcr-Abl myeloblastic (HL-60) and B lymphoblastic (SKW6.4) cell lines. Ectopic expression of Bcr-Abl conferred resistance to apoptosis induced by staurosporine and anti-Fas in HL-60 cells, but not in SKW6.4 cells, although increased phosphotyrosine containing proteins could be easily observed in SKW6.4.Bcr-Abl cells. The protein levels of Bcl-xL, Mcl-1 and Flip detected by western-blot were greater in HL-60.Bcr.Abl, when compared to wild type HL-60 cells. In contrast, the proapoptotic protein Bid was considerably reduced in HL-60. Bcr-abl cells. Two independent lines of SKW6.4.Bcr-Abl cells had a small reduction of in Bid levels, but no difference was observed in the expression of the anti-apoptotic proteins Bcl-xL, Mcl-1 and Flip. At the mRNA level SKW6.4 and SKW.Bcr-Abl presented similar expression of Bcl-xL, Mcl-1 and Flip. In addition a greater expression of anti-apoptotitc proteins A1 (IDV A1/actin=0.6) and Bcl-w (IDV Bcl-w/actin=1.6) was found in SKW6.4.Bcr-Abl compare to SKW (0.2 and 0.01, respectively) wild type. Interestingly, the upregulated levels of these anti-apoptotic genes were not sufficient to prevent apoptosis in these cells. Taken together these results suggest that Bcr-abl is not capable of protecting SKW6.4 cells from apoptosis induced by staurosporine and anti-Fas, perhaps because it interacts differently with the apoptotic machinery in B lymphoblasts compared to myeloblast cell lines. Further stydies are underway in our laboratory in order to better understand the Bcr-abl-mediated anti-apoptotic signaling in B lymphoblast cells.

The URNA Genes of Herpesvirus Saimiri (Strain C488) Are Dispensable for Transformation of Human T Cells In Vitro

1999 ◽  
Vol 73 (12) ◽  
pp. 10551-10555 ◽  
Author(s):  
Armin Ensser ◽  
André Pfinder ◽  
Ingrid Müller-Fleckenstein ◽  
Bernhard Fleckenstein
Keyword(s):  
Cell Culture ◽  
Herpesvirus Saimiri ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Human T Cell ◽  
Human T Cells ◽  
Small Nuclear Rnas ◽  
T Cell Lines

ABSTRACT The herpesvirus saimiri strain C488 genome contains five genes for small nuclear RNAs, termed herpesvirus saimiri URNAs (or HSURs). Using a cosmid-based approach, all HSURs were precisely deleted from the genome. The mutant virus replicated at levels that were similar to those of wild-type viruses in OMK cells. Although the HSURs are expressed in wild-type virus-transformed human T-cell lines, the deletion does not affect viral transformation in cell culture.

scholarly journals Mutations in fbiD (Rv2983) as a Novel Determinant of Resistance to Pretomanid and Delamanid in Mycobacterium tuberculosis

2020 ◽  
Vol 65 (1) ◽  
pp. e01948-20
Author(s):  
Dalin Rifat ◽  
Si-Yang Li ◽  
Thomas Ioerger ◽  
Keshav Shah ◽  
Jean-Philippe Lanoix ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Evidence ◽  
Clinical Samples ◽  
Loss Of Function ◽  
Wild Type ◽  
Content Type ◽  
Solid Media ◽  
High Level ◽  
Level Resistance

ABSTRACTThe nitroimidazole prodrugs delamanid and pretomanid comprise one of only two new antimicrobial classes approved to treat tuberculosis (TB) in 50 years. Prior in vitro studies suggest a relatively low barrier to nitroimidazole resistance in Mycobacterium tuberculosis, but clinical evidence is limited to date. We selected pretomanid-resistant M. tuberculosis mutants in two mouse models of TB using a range of pretomanid doses. The frequency of spontaneous resistance was approximately 10−5 CFU. Whole-genome sequencing of 161 resistant isolates from 47 mice revealed 99 unique mutations, of which 91% occurred in 1 of 5 genes previously associated with nitroimidazole activation and resistance, namely, fbiC (56%), fbiA (15%), ddn (12%), fgd (4%), and fbiB (4%). Nearly all mutations were unique to a single mouse and not previously identified. The remaining 9% of resistant mutants harbored mutations in Rv2983 (fbiD), a gene not previously associated with nitroimidazole resistance but recently shown to be a guanylyltransferase necessary for cofactor F420 synthesis. Most mutants exhibited high-level resistance to pretomanid and delamanid, although Rv2983 and fbiB mutants exhibited high-level pretomanid resistance but relatively small changes in delamanid susceptibility. Complementing an Rv2983 mutant with wild-type Rv2983 restored susceptibility to pretomanid and delamanid. By quantifying intracellular F420 and its precursor Fo in overexpressing and loss-of-function mutants, we provide further evidence that Rv2983 is necessary for F420 biosynthesis. Finally, Rv2983 mutants and other F420H2-deficient mutants displayed hypersusceptibility to some antibiotics and to concentrations of malachite green found in solid media used to isolate and propagate mycobacteria from clinical samples.

scholarly journals InsP7is a small-molecule regulator of NUDT3-mediated mRNA decapping and processing-body dynamics

2020 ◽  
Vol 117 (32) ◽  
pp. 19245-19253 ◽  
Author(s):  
Soumyadip Sahu ◽  
Zhenzhen Wang ◽  
Xinfu Jiao ◽  
Chunfang Gu ◽  
Nikolaus Jork ◽  
...  
Keyword(s):  
Stress Responses ◽  
Messenger Rna ◽  
Control Process ◽  
Stem Cell Differentiation ◽  
Wild Type ◽  
Inositol Pyrophosphate ◽  
Body Dynamics ◽  
Processing Body ◽  
The Stability

Regulation of enzymatic 5′ decapping of messenger RNA (mRNA), which normally commits transcripts to their destruction, has the capacity to dynamically reshape the transcriptome. For example, protection from 5′ decapping promotes accumulation of mRNAs into processing (P) bodies—membraneless, biomolecular condensates. Such compartmentalization of mRNAs temporarily removes them from the translatable pool; these repressed transcripts are stabilized and stored until P-body dissolution permits transcript reentry into the cytosol. Here, we describe regulation of mRNA stability and P-body dynamics by the inositol pyrophosphate signaling molecule 5-InsP7(5-diphosphoinositol pentakisphosphate). First, we demonstrate 5-InsP7inhibits decapping by recombinant NUDT3 (Nudix [nucleoside diphosphate linked moiety X]-type hydrolase 3) in vitro. Next, in intact HEK293 and HCT116 cells, we monitored the stability of a cadre of NUDT3 mRNA substrates following CRISPR-Cas9 knockout ofPPIP5Ks(diphosphoinositol pentakisphosphate 5-kinases type 1 and 2, i.e.,PPIP5KKO), which elevates cellular 5-InsP7levels by two- to threefold (i.e., within the physiological rheostatic range). ThePPIP5KKO cells exhibited elevated levels of NUDT3 mRNA substrates and increased P-body abundance. Pharmacological and genetic attenuation of 5-InsP7synthesis in the KO background reverted both NUDT3 mRNA substrate levels and P-body counts to those of wild-type cells. Furthermore, liposomal delivery of a metabolically resistant 5-InsP7analog into wild-type cells elevated levels of NUDT3 mRNA substrates and raised P-body abundance. In the context that cellular 5-InsP7levels normally fluctuate in response to changes in the bioenergetic environment, regulation of mRNA structure by this inositol pyrophosphate represents an epitranscriptomic control process. The associated impact on P-body dynamics has relevance to regulation of stem cell differentiation, stress responses, and, potentially, amelioration of neurodegenerative diseases and aging.

scholarly journals Allelic Exchange and Mutant Selection Demonstrate that Common Clinical embCAB Gene Mutations Only Modestly Increase Resistance to Ethambutol in Mycobacterium tuberculosis

2009 ◽  
Vol 54 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Hassan Safi ◽  
Robert D. Fleischmann ◽  
Scott N. Peterson ◽  
Marcus B. Jones ◽  
Behnam Jarrahi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
In Vitro Selection ◽  
Gene Mutations ◽  
Wild Type ◽  
Mutant Selection ◽  
Preferential Growth ◽  
Allelic Exchange ◽  
High Level ◽  
Isogenic Mutants

ABSTRACT Mutations within codon 306 of the Mycobacterium tuberculosis embB gene modestly increase ethambutol (EMB) MICs. To identify other causes of EMB resistance and to identify causes of high-level resistance, we generated EMB-resistant M. tuberculosis isolates in vitro and performed allelic exchange studies of embB codon 406 (embB406) and embB497 mutations. In vitro selection produced mutations already identified clinically in embB306, embB397, embB497, embB1024, and embC13, which result in EMB MICs of 8 or 14 μg/ml, 5 μg/ml, 12 μg/ml, 3 μg/ml, and 4 μg/ml, respectively, and mutations at embB320, embB324, and embB445, which have not been identified in clinical M. tuberculosis isolates and which result in EMB MICs of 8 μg/ml, 8 μg/ml, and 2 to 8 μg/ml, respectively. To definitively identify the effect of the common clinical embB497 and embB406 mutations on EMB susceptibility, we created a series of isogenic mutants, exchanging the wild-type embB497 CAG codon in EMB-susceptible M. tuberculosis strain 210 for the embB497 CGG codon and the wild-type embB406 GGC codon for either the embB406 GCC, embB406 TGC, embB406 TCC, or embB406 GAC codon. These new mutants showed 6-fold and 3- to 3.5-fold increases in the EMB MICs, respectively. In contrast to the embB306 mutants, the isogenic embB497 and embB406 mutants did not have preferential growth in the presence of isoniazid or rifampin (rifampicin) at their MICs. These results demonstrate that individual embCAB mutations confer low to moderate increases in EMB MICs. Discrepancies between the EMB MICs of laboratory mutants and clinical M. tuberculosis strains with identical mutations suggest that clinical EMB resistance is multigenic and that high-level EMB resistance requires mutations in currently unknown loci.

scholarly journals Wild type GAL4 binds cooperatively to the GAL1-10 UASG in vitro

1993 ◽  
Vol 268 (13) ◽  
pp. 9629-9635
Author(s):  
T. Kang ◽  
T. Martins ◽  
I. Sadowski
Keyword(s):  
Wild Type
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