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1.
Brief Bioinform ; 24(3)2023 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-37020334

RESUMO

RNA alternative splicing, a post-transcriptional stage in eukaryotes, is crucial in cellular homeostasis and disease processes. Due to the rapid development of the next-generation sequencing (NGS) technology and the flood of NGS data, the detection of differential splicing from RNA-seq data has become mainstream. A range of bioinformatic tools has been developed. However, until now, an independent and comprehensive comparison of available algorithms/tools at the event level is still lacking. Here, 21 different tools are subjected to systematic evaluation, based on simulated RNA-seq data where exact differential splicing events are introduced. We observe immense discrepancies among these tools. SUPPA, DARTS, rMATS and LeafCutter outperforme other event-based tools. We also examine the abilities of the tools to identify novel splicing events, which shows that most event-based tools are unsuitable for discovering novel splice sites. To improve the overall performance, we present two methodological approaches i.e. low-expression transcript filtering and tool-pair combination. Finally, a new protocol of selecting tools to perform differential splicing analysis for different analytical tasks (e.g. precision and recall rate) is proposed. Under this protocol, we analyze the distinct splicing landscape in the DUX4/IGH subgroup of B-cell acute lymphoblastic leukemia and uncover the differential splicing of TCF12. All codes needed to reproduce the results are available at https://github.com/mhjiang97/Benchmarking_DS.


Assuntos
Benchmarking , Software , RNA-Seq , Análise de Sequência de RNA/métodos , Splicing de RNA , Processamento Alternativo
2.
Blood ; 140(12): 1390-1407, 2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-35544603

RESUMO

Recurrent MEF2D fusions with poor prognosis have been identified in B-cell precursor ALL (BCP-ALL). The molecular mechanisms underlying the pathogenic function of MEF2D fusions are poorly understood. Here, we show that MEF2D-HNRNPUL1 (MH) knock-in mice developed a progressive disease from impaired B-cell development at the pre-pro-B stage to pre-leukemia over 10 to 12 months. When cooperating with NRASG12D, MH drove an outbreak of BCP-ALL, with a more aggressive phenotype than the NRASG12D-induced leukemia. RNA-sequencing identified key networks involved in disease mechanisms. In chromatin immunoprecipitation-sequencing experiments, MH acquired increased chromatin-binding ability, mostly through MEF2D-responsive element (MRE) motifs in target genes, compared with wild-type MEF2D. Using X-ray crystallography, the MEF2D-MRE complex was characterized in atomic resolution, whereas disrupting the MH-DNA interaction alleviated the aberrant target gene expression and the B-cell differentiation arrest. The C-terminal moiety (HNRNPUL1 part) of MH was proven to contribute to the fusion protein's trans-regulatory activity, cofactor recruitment, and homodimerization. Furthermore, targeting MH-driven transactivation of the HDAC family by using the histone deacetylase inhibitor panobinostat in combination with chemotherapy improved the overall survival of MH/NRASG12D BCP-ALL mice. Altogether, these results not only highlight MH as an important driver in leukemogenesis but also provoke targeted intervention against BCP-ALL with MEF2D fusions.


Assuntos
Proteínas de Fusão Oncogênica , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animais , Cromatina , DNA/metabolismo , Inibidores de Histona Desacetilases , Fatores de Transcrição MEF2/genética , Fatores de Transcrição MEF2/metabolismo , Camundongos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Panobinostat , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , RNA
3.
FASEB J ; 37(6): e22986, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37219517

RESUMO

PML nuclear body (NB) malfunction often leads to acute leukemia outbreaks and other severe diseases. PML NB rescue is the molecular basis of arsenic success in acute promyelocytic leukemia (APL) treatment. However, it is unclear how PML NBs are assembled. Here, we observed the presence of liquid-liquid phase separation (LLPS) in NB formation by fluorescence recovery after photobleaching (FRAP) experiment. Compared with the wild-type (WT) NBs, PML A216V derived from arsenic-resistant leukemia patients markedly crippled LLPS, but not altered the overall structure and PML RBCC oligomerization. In parallel, we also reported several Leu to Pro mutations that were critical to PML coiled-coil domain. FRAP characterization and comparison between L268P and A216V revealed markedly different LLPS activities in these mutant NBs. Transmission electron microscopy (TEM) inspections of LLPS-crippled and uncrippled NBs showed aggregation- and ring-like PML packing in A216V and WT/L268P NBs, respectively. More importantly, the correct LLPS-driven NB formation was the prerequisite for partner recruitment, post-translational modifications (PTMs), and PML-driven cellular regulations, such as ROS stress control, mitochondria production, and PML-p53-mediated senescence and apoptosis. Altogether, our results helped to define a critical LLPS step in PML NB biogenesis.


Assuntos
Arsênio , Leucemia , Humanos , Apoptose , Corpos Nucleares da Leucemia Promielocítica
4.
Protein Expr Purif ; 179: 105788, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33221504

RESUMO

MEF2D-fusions have recently been identified as one of the major oncogenic drivers in precursor B-cell acute lymphoblastic leukemia (B-ALL). More importantly, they are often associated with patients with poor prognosis in B-ALL. To have a better understanding of the pathogenic mechanism underpinning MEF2D-fusions-driven leukemogenesis, it's essential to uncover the related structure information. In this study, we expressed and purified the MEF2D N-terminal DNA binding domain. The recombinant protein was engineered by cloning the encoding gene into the expression vector pET-32 m. A series of chromatographic steps involving affinity, ion-exchange and gel-filtration chromatography were used to achieve a final purity of >95%. For the crystallization of the MEF2D-DNA complex, a double-stranded DNA encoding 5'-AACTATTTATAAGA-3' and 5'-TTCTTATAAATAGT-3' was used (Wu et al., 2010) [1]. The MEF2D-DNA crystal with the size of about 20 µm × 20 µm × 20 µm was obtained at a final concentration of 12 mg/ml at the reservoir condition containing 30% PEG1500. The X-ray examination showed that the MEF2D-DNA crystal diffracted to 4.5 Å resolution, and belonged to space group P1, with unit-cell parameters of a = 77.2 Å, b = 77.2 Å, c = 231.4 Å.


Assuntos
DNA , Proteínas Recombinantes , Sítios de Ligação/genética , Cromatografia Líquida , DNA/química , DNA/metabolismo , Humanos , Fatores de Transcrição MEF2/química , Fatores de Transcrição MEF2/genética , Fatores de Transcrição MEF2/isolamento & purificação , Fatores de Transcrição MEF2/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Difração de Raios X
5.
FASEB J ; 33(12): 14690-14702, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31702961

RESUMO

Almost all the outer membrane proteins (OMPs) fold into an invariant ß-barrel fold via the polypeptide-transport-associated (POTRA) motif and ß-barrel assembly machinery (BAM). However, whether and how poly-POTRAs interact with OMPs remain largely unknown. Here, we have characterized the structures of Haemophilus influenzae poly-POTRAs via X-ray crystallography, small angle X-ray scattering, and molecular dynamics simulation. Unexpectedly, crystal packing reveals a putative OMP travel pathway spiraled by the conserved α2-ß2 edges in poly-POTRAs. Supportively, the structure-based mutations targeting the OMP binding sites significantly disrupt OMP biogenesis, resulting in severe cell growth defects. Another notable feature in H. influenzae POTRA structures is flexibility. As characterized by ELISA assays, poly-POTRAs could recruit OMP substrates in a step-wise manner. More importantly, the restriction of POTRA-POTRA linkage and flexibility significantly impairs the BamA function and causes cell growth defect. Altogether, these results suggest that the ß-strand augmentations and intrinsic flexibility are important factors for BamA-OMP recruitment.-Ma, X., Wang, Q., Li, Y., Tan, P., Wu, H., Wang, P., Dong, X., Hong, L., Meng, G. How BamA recruits OMP substrates via poly-POTRAs domain.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Simulação de Dinâmica Molecular , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Sequência Conservada , Haemophilus influenzae , Mutação , Domínios Proteicos , Multimerização Proteica
6.
Kidney Int ; 88(3): 593-604, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26039629

RESUMO

Here, we report a genetic study of an extended family of Chinese ancestry with focal segmental glomerulosclerosis (FSGS), with one of the affected members also concurrently diagnosed with IgA nephropathy (IgAN). By genome-wide linkage analysis and subsequent sequencing, we identified an S85W mutation in the inverted formin 2 (INF2) gene that perfectly cosegregated with the kidney disease phenotype. The entire INF2 coding region was sequenced in 200 healthy controls, 55 families with FSGS, and 34 families with IgAN. This analysis identified a novel insertion, S129_Q130insVRQLS, in another FSGS pedigree. In vitro studies found that α-actinin 4 expression was decreased and INF2 showed perinuclear localization in S85W-transfected podocytes. Phosphorylation of serum response factor, and that its nuclear translation was decreased in S85W podocytes, indicated decreased activation in mutants. Abnormal actin organization was also found in S85W podocytes, while no change of microtubule structure was observed. Co-immunoprecipitation and immunofluorescence found decreased interaction between INF2 and Cdc42 in S85W podocytes. However, all these changes were not found in S129_Q130insVRQLS podocytes. The overall frequency of INF2 mutations was ~3.6% among Chinese familial FSGS, which was considerably lower than that from studies of European FSGS families. Thus, S85W but not the S129_Q130insVRQLS variant leads to podocyte cytoskeletal abnormalities, probably by impaired serum response factor phosphorylation.


Assuntos
Povo Asiático/genética , Glomerulosclerose Segmentar e Focal/genética , Proteínas dos Microfilamentos/genética , Mutação , Adulto , Animais , Estudos de Casos e Controles , Forma Celular , Células Cultivadas , China/epidemiologia , Citoesqueleto/metabolismo , Análise Mutacional de DNA , Feminino , Forminas , Frequência do Gene , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Glomerulosclerose Segmentar e Focal/diagnóstico , Glomerulosclerose Segmentar e Focal/etnologia , Glomerulosclerose Segmentar e Focal/metabolismo , Haplótipos , Hereditariedade , Humanos , Masculino , Camundongos , Proteínas dos Microfilamentos/metabolismo , Pessoa de Meia-Idade , Linhagem , Fenótipo , Fosforilação , Podócitos/metabolismo , Fatores de Risco , Fator de Resposta Sérica/metabolismo , Transfecção , Adulto Jovem , Proteína cdc42 de Ligação ao GTP/metabolismo
7.
EMBO J ; 30(18): 3864-74, 2011 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-21841773

RESUMO

Bacterial biofilms are complex microbial communities that are common in nature and are being recognized increasingly as an important determinant of bacterial virulence. However, the structural determinants of bacterial aggregation and eventual biofilm formation have been poorly defined. In Gram-negative bacteria, a major subgroup of extracellular proteins called self-associating autotransporters (SAATs) can mediate cell-cell adhesion and facilitate biofilm formation. In this study, we used the Haemophilus influenzae Hap autotransporter as a prototype SAAT to understand how bacteria associate with each other. The crystal structure of the H. influenzae Hap(S) passenger domain (harbouring the SAAT domain) was determined to 2.2 Å by X-ray crystallography, revealing an unprecedented intercellular oligomerization mechanism for cell-cell interaction. The C-terminal SAAT domain folds into a triangular-prism-like structure that can mediate Hap-Hap dimerization and higher degrees of multimerization through its F1-F2 edge and F2 face. The intercellular multimerization can give rise to massive buried surfaces that are required for overcoming the repulsive force between cells, leading to bacterial cell-cell interaction and formation of complex microcolonies.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Haemophilus influenzae/química , Multimerização Proteica , Serina Endopeptidases/química , Aderência Bacteriana , Proteínas da Membrana Bacteriana Externa/metabolismo , Cristalografia por Raios X , Modelos Biológicos , Modelos Moleculares , Ligação Proteica , Estrutura Quaternária de Proteína , Serina Endopeptidases/metabolismo
8.
Blood ; 121(4): 700-6, 2013 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-23169783

RESUMO

The integrin ß3-mediated c-Src priming and activation, via the SH3 domain, is consistently associated with diseases, such as the formation of thrombosis and the migration of tumor cells. Conventionally, activation of c-Src is often induced by the binding of proline-rich sequences to its SH3 domain. Instead, integrin ß3 uses R(760)GT(762) for priming and activation. Because of the lack of structural information, it is not clear where RGT will bind to SH3, and under what mechanism this interaction can prime/activate c-Src. In this study, we present a 2.0-Å x-ray crystal structure in which SH3 is complexed with the RGT peptide. The binding site lies in the "N"-Src loop of the SH3 domain. Structure-based site-directed mutagenesis showed that perturbation on the "N"-Src loop disrupts the interaction between the SH3 domain and the RGT peptide. Furthermore, the simulated c-Src:ß3 complex based on the crystal structure of SH3:RGT suggests that the binding of the RGT peptide might disrupt the intramolecular interaction between the SH3 and linker domains, leading to the disengagement of Trp260:"C"-helix and further activation of c-Src.


Assuntos
Integrina beta3/química , Integrina beta3/metabolismo , Proteínas Proto-Oncogênicas pp60(c-src)/química , Proteínas Proto-Oncogênicas pp60(c-src)/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Ativação Enzimática , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Proteínas Proto-Oncogênicas pp60(c-src)/genética , Alinhamento de Sequência , Domínios de Homologia de src
9.
Microbiology (Reading) ; 160(Pt 6): 1182-1190, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24687948

RESUMO

Haemophilus influenzae is a Gram-negative cocco-bacillus that initiates infection by colonizing the upper respiratory tract. Hap is an H. influenzae serine protease autotransporter protein that mediates adherence, invasion and microcolony formation in assays with human epithelial cells and is presumed to facilitate the process of colonization. Additionally, Hap mediates adherence to fibronectin, laminin and collagen IV, extracellular matrix (ECM) proteins that are present in the respiratory tract and are probably important targets for H. influenzae colonization. The region of Hap responsible for adherence to ECM proteins has been localized to the C-terminal 511 aa of the Hap passenger domain (HapS). In this study, we characterized the structural determinants of the interaction between HapS and fibronectin. Using defined fibronectin fragments, we established that Hap interacts with the fibronectin repeat fragment called FNIII(1-2). Using site-directed mutagenesis, we found a series of motifs in the C-terminal region of HapS that contribute to the interaction with fibronectin. Most of these motifs are located on the F1 and F3 faces of the HapS structure, suggesting that the F1 and F3 faces may be responsible for the HapS-fibronectin interaction.


Assuntos
Aderência Bacteriana , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Haemophilus influenzae/fisiologia , Domínios e Motivos de Interação entre Proteínas , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Humanos , Mutagênese Sítio-Dirigida , Ligação Proteica , Mapeamento de Interação de Proteínas
10.
Nat Commun ; 15(1): 1423, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38365836

RESUMO

Acute promyelocytic leukemia (APL) represents a paradigm for targeted differentiation therapy, with a minority of patients experiencing treatment failure and even early death. We here report a comprehensive single-cell analysis of 16 APL patients, uncovering cellular compositions and their impact on all-trans retinoic acid (ATRA) response in vivo and early death. We unveil a cellular differentiation hierarchy within APL blasts, rooted in leukemic stem-like cells. The oncogenic PML/RARα fusion protein exerts branch-specific regulation in the APL trajectory, including stem-like cells. APL cohort analysis establishes an association of leukemic stemness with elevated white blood cell counts and FLT3-ITD mutations. Furthermore, we construct an APL-specific stemness score, which proves effective in assessing early death risk. Finally, we show that ATRA induces differentiation of primitive blasts and patients with early death exhibit distinct stemness-associated transcriptional programs. Our work provides a thorough survey of APL cellular hierarchies, offering insights into cellular dynamics during targeted therapy.


Assuntos
Leucemia Promielocítica Aguda , Humanos , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Tretinoína/farmacologia , Diferenciação Celular , Linhagem Celular Tumoral , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo
11.
Trends Cancer ; 9(10): 855-870, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37407363

RESUMO

The biological regulation of transcription factors (TFs) and repressor proteins is an important mechanism for maintaining cell homeostasis. In B cell acute lymphoblastic leukemia (B-ALL) TF abnormalities occur at high frequency and are often recognized as the major driving factor in carcinogenesis. We provide an in-depth review of molecular mechanisms of six major TF rearrangements in B-ALL, including DUX4-rearranged (DUX4-R), MEF2D-R, ZNF384-R, ETV6-RUNX1 and TCF3-PBX1 fusions, and KMT2A-R. In addition, the therapeutic options and prognoses for patients who harbor these TF abnormalities are discussed. This review aims to provide an up-to-date panoramic view of how TF-based oncogenic fusions might drive carcinogenesis and impact on potential therapeutic exploration of B-ALL treatments.


Assuntos
Proteínas de Fusão Oncogênica , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Humanos , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Fatores de Transcrição/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Prognóstico , Carcinogênese/genética
12.
Clin Transl Med ; 13(12): e1514, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-38115701

RESUMO

BACKGROUND: IGH::DUX4 is frequently observed in 4% B-cell acute lymphoblastic leukaemia patients. Regarding the IGH::DUX4-driven transactivation and alternative splicing, which are the main reasons behind this acute leukaemia outbreak, it remains unclear how transcriptional cofactors contribute to this oncogenic process. Further investigation is required to elucidate their specific role in leukaemogenesis. METHODS: In order to investigate the cofactors of IGH::DUX4, integrated mining of Chromatin immunoprecipitation (ChIP)-sequencing and RNA-sequencing of leukaemia cells and patient samples were conducted. Furthermore, to elucidate the synergistic interaction between transcription factor 12 (TCF12) and IGH::DUX4, knockdown and knockout experiment, mammalian two-hybridisation assay, co-immunoprecipitation and in situ proximity ligation assays were carried out. Additionally, to further investigate the direct interaction between TCF12 and IGH::DUX4, AI-based structural simulations were utilised. Finally, to validate the synergistic role of TCF12 in promoting IGH::DUX4 leukaemia, cell proliferation, apoptosis and drug sensitivity experiments were performed. RESULTS: In this study, we observed that the IGH::DUX4 target gene TCF12 might be an important cofactor/helper for this oncogenic driver. The co-expression of IGH::DUX4 and TCF12 resulted in enhanced DUX4-driven transactivation. Supportively, knockdown and knockout of TCF12 significantly reduced expression of IGH::DUX4-driven target genes in leukaemia REH (a precursor B-cell leukaemia cell line) and NALM-6 cells (a precursor B-cell leukaemia cell line). Consistently, in TCF12 knockout cells, the expression of structure-based TCF12 mutant, but not wild-type TCF12, failed to restore the TCF12-IGH::DUX4 crosstalk and the synergistic transactivation. More importantly, the breakdown in TCF12-IGH::DUX4 cooperation impaired IGH::DUX4-driven leukaemia cell survival, caused sensitivity to the chemotherapy. CONCLUSIONS: Altogether, these results helped to define a previously unrecognised TCF12-mediated positive self-feedback regulatory mechanism in IGH::DUX4 leukaemia, which holds the potential to function as a pivotal drug target for the management of this particular form of leukaemia. HIGHLIGHTS: Transcription factor 12 (TCF12) is a new novel cofactor in IGH::DUX4 transcriptional complexes/machinery. TCF12 mediates a positive self-feedback regulatory mechanism in IGH::DUX4-driven oncogenic transaction. IGH::DUX4-TCF12 structure/cooperation might represent a potent target/direction in future drug design against B-cell acute lymphoblastic leukaemia.


Assuntos
Leucemia de Células B , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Animais , Humanos , Retroalimentação , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Linhagem Celular , Carcinogênese/genética , Mamíferos
13.
Front Med ; 17(4): 758-767, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37000349

RESUMO

With the recent ongoing autumn/winter 2022 COVID-19 wave and the adjustment of public health control measures, there have been widespread SARS-CoV-2 infections in Chinese mainland. Here we have analyzed 369 viral genomes from recently diagnosed COVID-19 patients in Shanghai, identifying a large number of sublineages of the SARS-CoV-2 Omicron family. Phylogenetic analysis, coupled with contact history tracing, revealed simultaneous community transmission of two Omicron sublineages dominating the infections in some areas of China (BA.5.2 mainly in Guangzhou and Shanghai, and BF.7 mainly in Beijing) and two highly infectious sublineages recently imported from abroad (XBB and BQ.1). Publicly available data from August 31 to November 29, 2022 indicated an overall severe/critical case rate of 0.035% nationwide, while analysis of 5706 symptomatic patients treated at the Shanghai Public Health Center between September 1 and December 26, 2022 showed that 20 cases (0.35%) without comorbidities progressed into severe/critical conditions and 153 cases (2.68%) with COVID-19-exacerbated comorbidities progressed into severe/critical conditions. These observations shall alert healthcare providers to place more resources for the treatment of severe/critical cases. Furthermore, mathematical modeling predicts this autumn/winter wave might pass through major cities in China by the end of the year, whereas some middle and western provinces and rural areas would be hit by the upcoming infection wave in mid-to-late January 2023, and the duration and magnitude of upcoming outbreak could be dramatically enhanced by the extensive travels during the Spring Festival (January 21, 2023). Altogether, these preliminary data highlight the needs to allocate resources to early diagnosis and effective treatment of severe cases and the protection of vulnerable population, especially in the rural areas, to ensure the country's smooth exit from the ongoing pandemic and accelerate socio-economic recovery.

14.
Blood Sci ; 4(3): 161-163, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36518591

RESUMO

B-cell acute lymphoblastic leukemia (B-ALL) is a malignant tumor originating from B-lineage lymphoid precursor cells. The incidence of B-ALL is about 80% in childhood acute leukemia and 20% in adults. In recent years, with standardized treatment guided by risk stratification, the long-term disease-free survival rate of children is about 80%, while that of adults is less than 40%. However, the specific pathogenesis of the newly identified B-ALL and the targeted therapy strategies have not been vigorously investigated. In this review, we highlight the recent breakthroughs in mechanistic studies and novel therapeutic options in DUX4- and MEF2D-subtype B-ALLs.

15.
Front Med (Lausanne) ; 9: 1021560, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36425099

RESUMO

The SARS-CoV-2 Omicron outbreak is ongoing in Shanghai, home to 25 million population. Here, we presented a novel mathematical model to evaluate the Omicron spread and Zero-COVID strategy. Our model provided important parameters, the average quarantine ratio, the detection interval from being infected to being tested positive, and the spreading coefficient to understand the epidemic progression better. Moreover, we found that the key to a relatively accurate long-term forecast was to take the variation/relaxation of the parameters into consideration based on the flexible execution of the quarantine policy. This allowed us to propose the criteria for estimating the parameters and outcome for the ending stage that is likely to take place in late May. Altogether, this model helped to give a correct mathematical appraisal of the SARS-CoV-2 Omicron outbreak under the strict Zero-COVID policy in China.

16.
Acta Crystallogr F Struct Biol Commun ; 77(Pt 4): 105-112, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33830075

RESUMO

AGAP1 is often considered to regulate membrane trafficking, protein transport and actin cytoskeleton dynamics. Recent studies have shown that aberrant expression of AGAP1 is associated with many diseases, including neurodevelopmental disorders and acute lymphoblastic leukemia. It has been proposed that the GTP-binding protein-like domain (GLD) is involved in the binding of cofactors and thus regulates the catalytic activity of AGAP1. To obtain a better understanding of the pathogenic mechanism underpinning AGAP1-related diseases, it is essential to obtain structural information. Here, the GLD (residues 70-235) of AGAP1 was overexpressed in Escherichia coli BL21 (DE3) cells. Affinity and gel-filtration chromatography were used to obtain AGAP1GLD with high purity for crystallization. Using the hanging-drop vapor-diffusion method with the protein at a final concentration of 20 mg ml-1, AGAP1GLD protein crystals of suitable size were obtained. The crystals were found to diffract to 3.0 Šresolution and belonged to space group I4, with unit-cell parameters a = 100.39, b = 100.39, c = 48.08 Å. The structure of AGAP1GLD exhibits the highly conserved functional G1-G5 loops and is generally similar to other characterized ADP-ribosylation factor (Arf) GTPase-activating proteins (GAPs), implying an analogous function to Arf GAPs. Additionally, this study indicates that AGAP1 could be classified as a type of NTPase, the activity of which might be regulated by protein partners or by its other domains. Taken together, these results provide insight into the regulatory mechanisms of AGAP1 in cell signaling.


Assuntos
Cristalografia por Raios X/métodos , Proteínas de Ligação ao GTP/química , Proteínas de Ligação ao GTP/genética , Proteínas Ativadoras de GTPase/química , Proteínas Ativadoras de GTPase/genética , Sequência de Aminoácidos , Humanos , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
17.
Cancer Commun (Lond) ; 41(11): 1116-1136, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34699692

RESUMO

BACKGROUND: Abnormal alternative splicing is frequently associated with carcinogenesis. In B-cell acute lymphoblastic leukemia (B-ALL), double homeobox 4 fused with immunoglobulin heavy chain (DUX4/IGH) can lead to the aberrant production of E-26 transformation-specific family related gene abnormal transcript (ERGalt ) and other splicing variants. However, the molecular mechanism underpinning this process remains elusive. Here, we aimed to know how DUX4/IGH triggers abnormal splicing in leukemia. METHODS: The differential intron retention analysis was conducted to identify novel DUX4/IGH-driven splicing in B-ALL patients. X-ray crystallography, small angle X-ray scattering (SAXS), and analytical ultracentrifugation were used to investigate how DUX4/IGH recognize double DUX4 responsive element (DRE)-DRE sites. The ERGalt biogenesis and B-cell differentiation assays were performed to characterize the DUX4/IGH crosslinking activity. To check whether recombination-activating gene 1/2 (RAG1/2) was required for DUX4/IGH-driven splicing, the proximity ligation assay, co-immunoprecipitation, mammalian two hybrid characterizations, in vitro RAG1/2 cleavage, and shRNA knock-down assays were performed. RESULTS: We reported previously unrecognized intron retention events in C-type lectin domain family 12, member A abnormal transcript (CLEC12Aalt ) and chromosome 6 open reading frame 89 abnormal transcript (C6orf89alt ), where also harbored repetitive DRE-DRE sites. Supportively, X-ray crystallography and SAXS characterization revealed that DUX4 homeobox domain (HD)1-HD2 might dimerize into a dumbbell-shape trans configuration to crosslink two adjacent DRE sites. Impaired DUX4/IGH-mediated crosslinking abolishes ERGalt , CLEC12Aalt , and C6orf89alt biogenesis, resulting in marked alleviation of its inhibitory effect on B-cell differentiation. Furthermore, we also observed a rare RAG1/2-mediated recombination signal sequence-like DNA edition in DUX4/IGH target genes. Supportively, shRNA knock-down of RAG1/2 in leukemic Reh cells consistently impaired the biogenesis of ERGalt , CLEC12Aalt , and C6orf89alt . CONCLUSIONS: All these results suggest that DUX4/IGH-driven DNA crosslinking is required for RAG1/2 recruitment onto the double tandem DRE-DRE sites, catalyzing V(D)J-like recombination and oncogenic splicing in acute lymphoblastic leukemia.


Assuntos
Proteínas de Homeodomínio , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animais , Carcinogênese , DNA , Proteínas de Homeodomínio/genética , Humanos , Lectinas Tipo C , Receptores Mitogênicos , Recombinação Genética , Espalhamento a Baixo Ângulo , Difração de Raios X
18.
Mol Membr Biol ; 26(3): 136-45, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19225986

RESUMO

The formation of homo-oligomeric assemblies is a well-established characteristic of many soluble proteins and enzymes. Oligomerization has been shown to increase protein stability, allow allosteric cooperativity, shape reaction compartments and provide multivalent interaction sites in soluble proteins. In comparison, our understanding of the prevalence and reasons behind protein oligomerization in membrane proteins is relatively sparse. Recent progress in structural biology of bacterial outer membrane proteins has suggested that oligomerization may be as common and versatile as in soluble proteins. Here we review the current understanding of oligomerization in the bacterial outer membrane from a structural and functional point of view.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Multimerização Proteica , Proteínas da Membrana Bacteriana Externa/fisiologia , Conformação Proteica
19.
Blood Sci ; 2(1): 7-10, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35399865

RESUMO

PML nuclear bodies (NBs), which are increasingly recognized as the central hub of many cellular signaling events, are superassembled spherical complexes with diameters of 0.1-2 µm. Recent studies reveal that RING tetramerization and B1-box polymerization are key factors to the overall PML NBs assembly. The productive RBCC oligomerization allows subsequent PML biogenesis steps, including the PML auto-sumoylation and partners recruitment via SUMO-SIM interactions. In promyelocytic leukemia, the oncoprotein PML/RARα (P/R) inhibits PML NBs assembly and leads to a full-fledged leukemogenesis. In this review, we review the recent progress in PML and acute promyelocytic leukemia fields, highlighting the protein oligomerization as an important direction of future targeted therapy.

20.
Trends Cancer ; 6(10): 889-906, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32527650

RESUMO

Targeted therapy has become increasingly important in cancer therapy. For example, targeting the promyelocytic leukemia PML protein in leukemia has proved to be an effective treatment. PML is the core component of super-assembled structures called PML nuclear bodies (NBs). Although this nuclear megaDalton complex was first observed in the 1960s, the mechanism of its assembly remains poorly understood. We review recent breakthroughs in the PML field ranging from a revised assembly mechanism to PML-driven genome organization and carcinogenesis. In addition, we highlight that oncogenic oligomerization might also represent a promising target in the treatment of leukemias and solid tumors.


Assuntos
Neoplasias/metabolismo , Proteína da Leucemia Promielocítica/metabolismo , Animais , Carcinogênese , Humanos , Neoplasias/patologia , Neoplasias/terapia
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