scholarly journals Dependence on Myb expression is attenuated in myeloid leukaemia with N-terminal CEBPA mutations

2019 ◽  
Vol 2 (2) ◽  
pp. e201800207 ◽  
Author(s):  
Giacomo Volpe ◽  
Pierre Cauchy ◽  
David S Walton ◽  
Carl Ward ◽  
Daniel Blakemore ◽  
...  
Keyword(s):  
Myeloid Leukaemia ◽  
Normal Karyotype ◽  
Sequencing Data ◽  
Mutational Status ◽  
C Terminus ◽  
Chromatin Immunoprecipitation Sequencing ◽  
Cebpa Mutations ◽  
First Time ◽  
Do So

Mutations at the N- or C-terminus of C/EBPα are frequent in acute myeloid leukaemia (AML) with normal karyotype. Here, we investigate the role of the transcription factor Myb in AMLs driven by different combinations of CEBPA mutations. Using knockdown of Myb in murine cell lines modelling the spectrum of CEBPA mutations, we show that the effect of reduced Myb depends on the mutational status of the two Cebpa alleles. Importantly, Myb knockdown fails to override the block in myeloid differentiation in cells with biallelic N-terminal C/EBPα mutations, demonstrating for the first time that the dependency on Myb is much lower in AML with this mutational profile. By comparing gene expression following Myb knockdown and chromatin immunoprecipitation sequencing data for the binding of C/EBPα isoforms, we provide evidence for a functional cooperation between C/EBPα and Myb in the maintenance of AML. This co-dependency breaks down when both alleles of CEBPA harbour N-terminal mutations, as a subset of C/EBPα-regulated genes only bind the short p30 C/EBPα isoform and, unlike other C/EBPα-regulated genes, do so without a requirement for Myb.

Role of CEBPA-Mutations in AML with Prognostically Intermediate Cytogenetics: Data of the AMLCG Study Group and Gene Expression Analyses.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 571-571 ◽  
Author(s):  
Susanne Schnittger ◽  
Viola Conrad ◽  
Alexander Kohlmann ◽  
Martin Dugas ◽  
Sylvia Merk ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Prognostic Significance ◽  
Normal Karyotype ◽  
Prognostic Impact ◽  
Reciprocal Translocations ◽  
Specific Expression ◽  
Cebpa Mutations ◽  
Cluster 2

Abstract Approximately 50% of acute myeloid leukemia (AML) have no karyotype changes or those with yet unknown prognostic significance. They are usually pooled together into the prognostically intermediate group. Here we approached the role of CEBPA mutations within this AML subgroup. In total, 255 AML, 237 with normal and 18 with “other” intermediate risk group karyotypes were screened for CEBPA mutations by sequencing. The total incidence of CEBPA mutations was 51/255 (20%) (48/237 (20.3%) in the normal and 3/18 (16.7%) in the “other” karyotypes). Most of the patients showed an M1 (n=16), or M2 (n=25) morphology, but there were also some with FAB M0 (n=1), M4 (n=4), M5 (n=3), and M6 (n=2). CEBPA+ cases were younger as compared to the CEBPA- cases (54.7 vs. 60.0, p=0.023). Leukocyte und platelet counts were similar. Clinical follow up data were available for 191 (37 mutated, 154 unmutated) patients. OS and EFS were significantly better in the patients with compared to those without CEBPA mutations (median 1092 vs. 259 days, p=0.0072; 375 vs. 218 days, p=0.0102, respectively). In addition, 18/42 (42.9%) of CEBPA+ cases had an FLT3-LM, 4/40 (10%) an FLT3-TKD, 4/41 (9.8%) an MLL-PTD, 3/34 (8.8%) an NRAS, 2/40 (5%) a KITD816 mutation. In four cases 2 additional mutations were detected: 1 x FLT3-LM+KITD816, 1 x FLT3-LM+FLT3-TKD, and 2 x MLL-PTD+FLT3-LM. The favorable prognostic impact of CEBPA mutations was not affected by additional mutations. Furthermore, 22 of the CEBPA+ case were analyzed by microarray analysis using the U133A+B array set (Affymetrix) and compared to the expression profile of 131 CEBPA- normal karyotype AML, as well as to 204 AML characterized by the reciprocal translocations t(15;17) (n=43), t(8;21) (n=36), inv(16) (n=48), t(11q23) (n=50), inv(3) (n=27). The discrimination of CEBPA+ cases and reciprocal translocations revealed a classification accuracy of 94.7% with 75% sensitivity and 98.5% specificity. However, the CEPBA+ cases did not show a specific expression pattern within the total group with normal karyotype and could not be discriminated from CEBPA- cases. By use of PCA and hierachical cluster analysis it was obvious that the CEBPA+ cases separated into two domains. One subcluster (cluster 1) was distributed among the cases with CEBPA- normal karyotype AML. A second cluster (cluster 2) was very close to the t(8;21) cases. Accordingly, cases of cluster 2 similar to t(8;21) and in contrast to cluster 1 highly expressed MPO and had low expression of HOXA3, HOXA7, HOXA9, HOXB4, HOXB6, and PBX3. Using the top 100 differentially expressed genes and applying 100 runs of SVM with 2/3 of samples being randomly selected as training set and 1/3 as test set samples, groups A and B could be classified with an overall accuracy of 100% (sensitivity 100% and specificity 100%). A detailed analysis of the two subclusters showed that all 8 cases of cluster 1 revealed mutations in the TAD2 domain of CEBPA and 6 of these had an FLT3-LM in addition. In contrast, 12/14 cases of cluster 2 had mutations that lead to an N-terminal stop and only 2 had an FLT3-LM. Thus these two subclusters have biological differences that may explain the different gene expression patterns. Despite the different functional consequences of the mutations in the two CEBPA-clusters no differences with respect to FAB type and prognosis were found between cluster 1 and 2.

Prognostic relevance of FLT3-TKD mutations in AML: the combination matters—an analysis of 3082 patients

Blood ◽  
2008 ◽  
Vol 111 (5) ◽  
pp. 2527-2537 ◽  
Author(s):  
Ulrike Bacher ◽  
Claudia Haferlach ◽  
Wolfgang Kern ◽  
Torsten Haferlach ◽  
Susanne Schnittger
Keyword(s):  
Normal Karyotype ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Survival Prognosis ◽  
Total Cohort ◽  
Mutational Status ◽  
High Incidence ◽  
Cebpa Mutations ◽  
Peripheral Leukocytes

We characterized the mutational status of the FLT3 tyrosine kinase domain (FLT3-TLD) in 3082 patients with newly diagnosed AML. FLT3-TKD mutations were detected in 147 of 3082 (4.8%) patients. Similar to the FLT3 juxtamembrane domain mutations (FLT3-LM), there was a high correlation of FLT3-TKD mutations with normal karyotype (88 of 1472; 6.0%). FLT3-TKD mutations were most frequent in the AML FAB subtypes M5b (15 of 114; 13.2%), M3v (6 of 51; 11.8%), and M4 (39 of 484; 8.1%). Similar to FLT3-LM, the FLT3-TKD mutations show elevated peripheral leukocytes compared with FLT3wt AML. FLT3-TKD had a high incidence in cases with NPM1 mutations (23 of 262; 8.8%), CEBPA mutations (6 of 76; 7.9%), and NRAS mutations (6 of 78; 7.7%). FLT3-TKD in combination with FLT3-LM (17 of 594 patients; 2.9%) and KITD816 (1 of 44; 2.3%) was rare. Unlike the FLT3-LM, which are associated with inferior survival, prognosis was not influenced by FLT3-TKD in the total cohort of 1720 cases, where follow-up data were available (97 FLT3-TKD; 1623 FLT3-WT). In t(15;17)/PML-RARA with FLT3-TKD mutations, in FLT3-LM/TKD double-mutated, and in MLL-PTD/TKD double-mutated cases prognosis was unfavorably influenced by FLT3-TKD mutations. In contrast, we found an additional favorable impact of FLT3-TKD on EFS in prognostically favorable AML with NPM1- or CEBPA mutations.

Waiting for the Right One: The Role of Social Proximity and Location in the Decision to Use Cannabis for the First Time

2018 ◽  
Vol 48 (4) ◽  
pp. 625-644 ◽  
Author(s):  
Martin Bouchard ◽  
Krysta L. Dawson ◽  
Morena Anamali
Keyword(s):  
Substance Use ◽  
Social Context ◽  
Social Contact ◽  
Factors Associated ◽  
The Social ◽  
Canadian City ◽  
The Right ◽  
First Time ◽  
Do So

The study examines the social context of a cannabis offer, an outcome rarely examined in research on substance use. Drawing from a survey conducted among 15-year-old students in a mid-sized Canadian city, we examine (a) the differences between three types of users (immediate, late, and nonusers) and (b) the factors associated with accepting a cannabis offer more quickly. The findings show that 40% of the sample received an offer, that 25% of those who accept an offer do so on the first occasion, and that among the others, it takes up to seven offers before accepting. The social context of the offer distinguishes between the types of users, and offers are accepted more quickly when adolescents are first offered by a close social contact, and when the offer occurs in familiar settings. The study also identifies a type of nonuser, those who are exposed to drugs but decide not to participate.

scholarly journals SUMOylome Modulates Intraflagellar Transport Machinery and Eukaryotic Cilia Motility

2021 ◽  
Author(s):  
Komal Sharma ◽  
Irina Sizova ◽  
Girdhar Pandey ◽  
Peter Hegemann ◽  
Suneel Kateriya
Keyword(s):  
Functional Role ◽  
Intraflagellar Transport ◽  
Small Gtpase ◽  
The Other ◽  
Signaling Proteins ◽  
Sumoylation Site ◽  
C Terminus ◽  
First Time ◽  
Insight Into

Abstract Translocation of channelrhodopsins (ChRs) is mediated by intraflagellar transport (IFT) machinery. However, the functional role of the network containing photoreceptors, IFT and other proteins in controlling cilia motility of the alga is still not fully delineated. In the current study, we identified two important motifs at the C-terminus of ChR1. One of them is similar to a known ciliary targeting sequence that specifically interacts with a small GTPase, and the other is a SUMOylation site. For the first time, experimental data provide an insight into the role of SUMOylation in the modulation of IFT & ChR1. Blocking of SUMOylation affected the phototaxis of C. reinhardtii cells. This implies SUMOylation based regulation of protein network controlling photomotility. The conservation of SUMOylation site pattern as analyzed for the relevant photoreceptors, IFT and its associated signaling proteins in other ciliated green algae suggested SUMOylation based photobehavioural response across the microbes. This report establishes a link between evolutionary conserved SUMOylation and ciliary machinery for the maintenance and functioning of cilia across the eukaryotes. Our enriched SUMOylome of C. reinhardtii comprehends the proteins related to ciliary development and, photo-signaling, along with homologue(s) associated to human ciliopathies as SUMO targets.

Genes Located within the del(9q) Commonly Deleted Region Are Down-Regualted in Acute Myeloid Leukaemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2040-2040
Author(s):  
Zheng Zhao ◽  
Sarah Daly ◽  
John Liu Yin ◽  
David Sweetser ◽  
Jacqueline Boultwood ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Normal Karyotype ◽  
Complex Karyotype ◽  
Down Regulation ◽  
Expression Levels ◽  
Normal Individuals ◽  
Low Expression ◽  
Acute Myeloid

Abstract Deletions of 9q are recurring cytogenetic abnormalities in acute myeloid leukaemia (AML). In approximately one-third of cases del(9q) occurs in association with t(8;21). We have previously identified a 2.4Mb region located on 9q21.32–21.33 which is deleted in cases of del(9q) AML - the del(9q) commonly deleted region (CDR). This region encodes 11 genes which we have also previously shown not to be mutated in del(9q) AML. In order to further investigate the role of these genes in AML and in particular to elucidate the pathogenesis of del(9q) AML we have examined the expression of these genes in AML. RNA was extracted from the bone marrow or peripheral blood of patients with AML at the time of diagnosis. Patient samples from the following cytogenetic subgroups were included in this study: (1) del(9q) AML (n=8) - this includes 3 patients with associated t(8;21); (2) t(8;21) but no del(9q) (n=15); (3) Normal karyotype (n=6); (4) Complex Karyotype (n=6). Taqman assays were designed for 9 of the 11 genes located within the del(9q) CDR: FRMD3; ENSG00000148057; UBQLN1; GKAP42; Q9UF54; Q8N2B1; Q9H9A7; SLC28A3; NTRK2. For the other 2 genes within the region Taqman assays could not be performed because of uniformly low expression levels (Q8IZ41) and lack of specificity of primer-design (HNRPK). CD34-purified progenitors from normal individuals were used as controls. It was found that 6 of the 9 genes were significantly down-regulated in del(9q) AML (p<0.05): ENSG00000148057; UBQLN1; Q9UF54; Q8N2B1; Q9H9A7; NTRK2. Since del(9q) is commonly associated with t(8;21), cases of t(8;21) in which del(9q) was not present were also analysed for the expression levels of the del(9q) CDR genes. It was found that 5 of the 9 genes were significantly down regulated in t(8;21) AML (ENSG00000148057; Q9UF54; Q8N2B1; Q9H9A7; SLC28A3) (p<0.05). Only two of these genes were found to be down-regulated in AML of normal karyotype (Q9H9A7 and UBQLN1) (p<0.05) and no significant down-regulation was detected in any of these genes in AML of complex karyotype. Our findings indicate that several genes from within the del(9q) AML CDR are down-regulated in del(9q) AML. A similar pattern of down-regulation is found in cases of t(8;21) even in the absence of del(9q) AML. This suggests that down-regulation of one or more of these genes may be important in the pathogenesis of AML. It may therefore be hypothesized that this pattern of gene down-regulation provides a mechanism common to the development of AML with both del(9q) and t(8;21).

scholarly journals Agrobacterium-Mediated T-DNA Transfer and Integration by Minimal VirD2 Consisting of the Relaxase Domain and a Type IV Secretion System Translocation Signal

2009 ◽  
Vol 22 (11) ◽  
pp. 1356-1365 ◽  
Author(s):  
Maartje van Kregten ◽  
Beatrice I. Lindhout ◽  
Paul J. J. Hooykaas ◽  
Bert J. van der Zaal
Keyword(s):  
Secretion System ◽  
Type Iv Secretion ◽  
Type Iv Secretion System ◽  
Terminal Part ◽  
Type Iv ◽  
C Terminus ◽  
Localization Signal ◽  
Translocation Domain ◽  
First Time

The VirD2 protein of Agrobacterium tumefaciens is essential for processing and transport of the T-DNA. It has at least three functional domains: a relaxase domain at the N terminus, a bipartite nuclear localization signal (NLS), and a sequence called ω at the C terminus. We confirm here that deletions of the C-terminal part of VirD2 led to lack of transfer of T-DNA but, for the first time, we report that virulence is restored when these truncations are supplemented at the C terminus by a short translocation signal from the VirF protein. The lack of virulence of C-terminal deletions suggests that the C-terminal part contains all or part of the translocation signal of VirD2. Using a novel series of mutant VirD2 proteins, the C-terminal half of VirD2 was further investigated. We demonstrate that the C-terminal 40 amino acids of VirD2, which include the NLS and ω, contain all or part of the translocation domain necessary for transport of VirD2 into plant cells, while another element is present in the middle of the protein. The finding that a type IV secretion system transport signal at the C terminus of VirD2 is necessary for virulence provides evidence for the role of VirD2 as a pilot protein driving translocation of the T-strand.

scholarly journals CD8 T cells and antibodies drive SARS-CoV-2 evolution in chronic infection

2021 ◽  
Author(s):  
Elham Khatamzas ◽  
Maximilian Muenchhoff ◽  
Alexandra Rehn ◽  
Alexander Graf ◽  
Johannes Hellmuth ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Human Leukocyte ◽  
Sequencing Data ◽  
Plasma Therapy ◽  
Leukocyte Antigen ◽  
T Cell Recognition ◽  
First Time

Abstract ​​Since its recent zoonotic spill-over severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is constantly adapting to the human host as illustrated by the emergence of variants of concern with increased transmissibility and immune evasion. Prolonged replication in immunosuppressed individuals and evasion from spike-specific antibodies is known to drive intra-host SARS-CoV-2 evolution. Here we show for the first time the major role of CD8 T cells in SARS-CoV-2 evolution. In a patient with chronic, ultimately fatal infection, we observed three spike mutations that prevented neutralisation by convalescent plasma therapy. Moreover, at least four mutations in non-spike proteins emerged that hampered CD8 T-cell recognition of mutant epitopes, two of these occurred before spike mutations. A comparison with worldwide sequencing data showed that several of these T-cell escape mutations had emerged independently as homoplasies in multiple circulating lineages. We propose that human leukocyte antigen class I contributes to shaping the evolutionary landscape of SARS-CoV-2.

The role of MDR-related proteins in the prognosis of adult acute myeloid leukaemia (AML) with normal karyotype

2007 ◽  
Vol 25 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Daniela Damiani ◽  
Mario Tiribelli ◽  
Donatella Raspadori ◽  
Angela Michelutti ◽  
Alessandro Gozzetti ◽  
...  
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Normal Karyotype ◽  
Related Proteins ◽  
Acute Myeloid

scholarly journals Sterol 14α-demethylase activity in Streptomyces coelicolor A3(2) is associated with an unusual member of the CYP51 gene family

2002 ◽  
Vol 364 (2) ◽  
pp. 555-562 ◽  
Author(s):  
David C. LAMB ◽  
Kay FOWLER ◽  
Tobias KIESER ◽  
Nigel MANNING ◽  
Larissa M. PODUST ◽  
...  
Keyword(s):  
Streptomyces Coelicolor ◽  
Open Reading Frame ◽  
Reading Frame ◽  
E Coli ◽  
Transposon Insertion ◽  
Cell Extracts ◽  
C Terminus ◽  
Demethylase Activity ◽  
First Time

The annotation of the genome sequence of Streptomyces coelicolor A3(2) revealed a cytochrome P450 (CYP) resembling various sterol 14α-demethylases (CYP51). The putative CYP open reading frame (SC7E4.20) was cloned with a tetrahistidine tag appended to the C-terminus and expressed in Escherichia coli. Protein purified to electrophoretic homogeneity was observed to bind the 14-methylated sterols lanosterol and 24-methylene-24,25-dihydrolanosterol (24-MDL). Reconstitution experiments with E. coli reductase partners confirmed activity in 14α-demethylation for 24-MDL, but not lanosterol. An S. coelicolor A3(2) mutant containing a transposon insertion in the CYP51 gene, which will abolish synthesis of the functional haemoprotein, was isolated as a viable strain, the first time a CYP51 has been identified as non-essential. The role of this CYP in bacteria is intriguing. No sterol product was detected in non-saponifiable cell extracts of the parent S. coelicolor A3(2) strain or of the mutant. S. coelicolor A3(2) CYP51 contains very few of the conserved CYP51 residues and, even though it can catalyse 14α-demethylation, it probably has another function in Streptomyces. We propose that it is a member of a new CYP51 subfamily.

Sign in / Sign up

Export Citation Format

Share Document