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1.
Cell ; 173(2): 430-442.e17, 2018 04 05.
Article in English | MEDLINE | ID: mdl-29606353

ABSTRACT

Fetal hemoglobin (HbF, α2γ2) level is genetically controlled and modifies severity of adult hemoglobin (HbA, α2ß2) disorders, sickle cell disease, and ß-thalassemia. Common genetic variation affects expression of BCL11A, a regulator of HbF silencing. To uncover how BCL11A supports the developmental switch from γ- to ß- globin, we use a functional assay and protein binding microarray to establish a requirement for a zinc-finger cluster in BCL11A in repression and identify a preferred DNA recognition sequence. This motif appears in embryonic and fetal-expressed globin promoters and is duplicated in γ-globin promoters. The more distal of the duplicated motifs is mutated in individuals with hereditary persistence of HbF. Using the CUT&RUN approach to map protein binding sites in erythroid cells, we demonstrate BCL11A occupancy preferentially at the distal motif, which can be disrupted by editing the promoter. Our findings reveal that direct γ-globin gene promoter repression by BCL11A underlies hemoglobin switching.


Subject(s)
Carrier Proteins/metabolism , Fetal Hemoglobin/genetics , Nuclear Proteins/metabolism , Base Sequence , Binding Sites , Carrier Proteins/genetics , Cell Line , Chromatin/metabolism , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Erythroid Cells/cytology , Erythroid Cells/metabolism , Gene Editing , Humans , Nuclear Proteins/genetics , Promoter Regions, Genetic , Protein Isoforms/genetics , Protein Isoforms/metabolism , Repressor Proteins , Zinc Fingers/genetics , beta-Globins/genetics , beta-Thalassemia/genetics , beta-Thalassemia/pathology , gamma-Globins/genetics
2.
Mol Cell ; 83(13): 2206-2221.e11, 2023 Jul 06.
Article in English | MEDLINE | ID: mdl-37311463

ABSTRACT

Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of histone lysine acylation has been limited to gene transcriptional activation. Here, we report that histone H3 lysine 27 crotonylation (H3K27cr) directs gene transcriptional repression rather than activation. Specifically, H3K27cr in chromatin is selectively recognized by the YEATS domain of GAS41 in complex with SIN3A-HDAC1 co-repressors. Proto-oncogenic transcription factor MYC recruits GAS41/SIN3A-HDAC1 complex to repress genes in chromatin, including cell-cycle inhibitor p21. GAS41 knockout or H3K27cr-binding depletion results in p21 de-repression, cell-cycle arrest, and tumor growth inhibition in mice, explaining a causal relationship between GAS41 and MYC gene amplification and p21 downregulation in colorectal cancer. Our study suggests that H3K27 crotonylation signifies a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for transcriptional silencing and H3K27 acetylation for transcriptional activation.


Subject(s)
Chromatin , Histones , Mice , Animals , Chromatin/genetics , Histones/metabolism , Lysine/metabolism , Transcription Factors/metabolism , Gene Expression Regulation , Acetylation
3.
Nature ; 607(7918): 399-406, 2022 07.
Article in English | MEDLINE | ID: mdl-35768513

ABSTRACT

Small interfering RNAs (siRNAs) are the key components for RNA interference (RNAi), a conserved RNA-silencing mechanism in many eukaryotes1,2. In Drosophila, an RNase III enzyme Dicer-2 (Dcr-2), aided by its cofactor Loquacious-PD (Loqs-PD), has an important role in generating 21 bp siRNA duplexes from long double-stranded RNAs (dsRNAs)3,4. ATP hydrolysis by the helicase domain of Dcr-2 is critical to the successful processing of a long dsRNA into consecutive siRNA duplexes5,6. Here we report the cryo-electron microscopy structures of Dcr-2-Loqs-PD in the apo state and in multiple states in which it is processing a 50 bp dsRNA substrate. The structures elucidated interactions between Dcr-2 and Loqs-PD, and substantial conformational changes of Dcr-2 during a dsRNA-processing cycle. The N-terminal helicase and domain of unknown function 283 (DUF283) domains undergo conformational changes after initial dsRNA binding, forming an ATP-binding pocket and a 5'-phosphate-binding pocket. The overall conformation of Dcr-2-Loqs-PD is relatively rigid during translocating along the dsRNA in the presence of ATP, whereas the interactions between the DUF283 and RIIIDb domains prevent non-specific cleavage during translocation by blocking the access of dsRNA to the RNase active centre. Additional ATP-dependent conformational changes are required to form an active dicing state and precisely cleave the dsRNA into a 21 bp siRNA duplex as confirmed by the structure in the post-dicing state. Collectively, this study revealed the molecular mechanism for the full cycle of ATP-dependent dsRNA processing by Dcr-2-Loqs-PD.


Subject(s)
Cryoelectron Microscopy , Drosophila Proteins , Drosophila melanogaster , RNA Helicases , RNA, Double-Stranded , RNA, Small Interfering , RNA-Binding Proteins , Ribonuclease III , Adenosine Triphosphate , Animals , Binding Sites , Drosophila Proteins/chemistry , Drosophila Proteins/metabolism , Drosophila Proteins/ultrastructure , Phosphates/metabolism , Protein Conformation , RNA Helicases/chemistry , RNA Helicases/metabolism , RNA Helicases/ultrastructure , RNA, Double-Stranded/chemistry , RNA, Double-Stranded/metabolism , RNA, Double-Stranded/ultrastructure , RNA, Small Interfering/chemistry , RNA, Small Interfering/metabolism , RNA, Small Interfering/ultrastructure , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/ultrastructure , Ribonuclease III/chemistry , Ribonuclease III/metabolism , Ribonuclease III/ultrastructure
4.
Proc Natl Acad Sci U S A ; 121(5): e2309384121, 2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38252835

ABSTRACT

High-quality specimen preparation plays a crucial role in cryo-electron microscopy (cryo-EM) structural analysis. In this study, we have developed a reliable and convenient technique called the graphene sandwich method for preparing cryo-EM specimens. This method involves using two layers of graphene films that enclose macromolecules on both sides, allowing for an appropriate ice thickness for cryo-EM analysis. The graphene sandwich helps to mitigate beam-induced charging effect and reduce particle motion compared to specimens prepared using the traditional method with graphene support on only one side, therefore improving the cryo-EM data quality. These advancements may open new opportunities to expand the use of graphene in the field of biological electron microscopy.


Subject(s)
Graphite , Cryoelectron Microscopy , Data Accuracy , Motion
5.
Nat Methods ; 20(1): 123-130, 2023 01.
Article in English | MEDLINE | ID: mdl-36522503

ABSTRACT

Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness. We show that the uniform thin ice on UFG improves the image quality of vitrified specimens. Using such a method we successfully determined the three-dimensional structures of hemoglobin (64 kDa), α-fetoprotein (67 kDa) with no symmetry, and streptavidin (52 kDa) at a resolution of 3.5 Å, 2.6 Å and 2.2 Å, respectively. Furthermore, our results demonstrate the potential of UFG for the fields of cryo-electron tomography and structure-based drug discovery.


Subject(s)
Graphite , Cryoelectron Microscopy/methods , Graphite/chemistry , Macromolecular Substances , Electron Microscope Tomography
6.
Nature ; 568(7752): 344-350, 2019 04.
Article in English | MEDLINE | ID: mdl-30944469

ABSTRACT

Stem cells underlie tissue homeostasis, but their dynamics during ageing-and the relevance of these dynamics to organ ageing-remain unknown. Here we report that the expression of the hemidesmosome component collagen XVII (COL17A1) by epidermal stem cells fluctuates physiologically through genomic/oxidative stress-induced proteolysis, and that the resulting differential expression of COL17A1 in individual stem cells generates a driving force for cell competition. In vivo clonal analysis in mice and in vitro 3D modelling show that clones that express high levels of COL17A1, which divide symmetrically, outcompete and eliminate adjacent stressed clones that express low levels of COL17A1, which divide asymmetrically. Stem cells with higher potential or quality are thus selected for homeostasis, but their eventual loss of COL17A1 limits their competition, thereby causing ageing. The resultant hemidesmosome fragility and stem cell delamination deplete adjacent melanocytes and fibroblasts to promote skin ageing. Conversely, the forced maintenance of COL17A1 rescues skin organ ageing, thereby indicating potential angles for anti-ageing therapeutic intervention.


Subject(s)
Homeostasis , Skin Aging/pathology , Skin Aging/physiology , Skin/cytology , Skin/pathology , Stem Cells/cytology , Stem Cells/pathology , Animals , Atrophy , Autoantigens/chemistry , Autoantigens/metabolism , Cell Division , Cell Proliferation , Clone Cells/cytology , Epidermal Cells/cytology , Epidermal Cells/pathology , Female , Genome , Hemidesmosomes/pathology , Male , Mice , Mice, Inbred C57BL , Models, Animal , Non-Fibrillar Collagens/chemistry , Non-Fibrillar Collagens/metabolism , Oxidative Stress , Proteolysis , Collagen Type XVII
7.
Mol Cell ; 67(6): 974-989.e6, 2017 Sep 21.
Article in English | MEDLINE | ID: mdl-28890335

ABSTRACT

During autophagosome formation in mammalian cells, isolation membranes (IMs; autophagosome precursors) dynamically contact the ER. Here, we demonstrated that the ER-localized metazoan-specific autophagy protein EPG-3/VMP1 controls ER-IM contacts. Loss of VMP1 causes stable association of IMs with the ER, thus blocking autophagosome formation. Interaction of WIPI2 with the ULK1/FIP200 complex and PI(3)P contributes to the formation of ER-IM contacts, and these interactions are enhanced by VMP1 depletion. VMP1 controls contact formation by promoting SERCA (sarco[endo]plasmic reticulum calcium ATPase) activity. VMP1 interacts with SERCA and prevents formation of the SERCA/PLN/SLN inhibitory complex. VMP1 also modulates ER contacts with lipid droplets, mitochondria, and endosomes. These ER contacts are greatly elevated by the SERCA inhibitor thapsigargin. Calmodulin acts as a sensor/effector to modulate the ER contacts mediated by VMP1/SERCA. Our study provides mechanistic insights into the establishment and disassociation of ER-IM contacts and reveals that VMP1 modulates SERCA activity to control ER contacts.


Subject(s)
Autophagosomes/enzymology , Endoplasmic Reticulum/enzymology , Intracellular Membranes/enzymology , Membrane Proteins/metabolism , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , Animals , Animals, Genetically Modified , Autophagy-Related Protein-1 Homolog/genetics , Autophagy-Related Protein-1 Homolog/metabolism , Autophagy-Related Proteins , COS Cells , CRISPR-Cas Systems , Caenorhabditis elegans/enzymology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Calcium-Binding Proteins/metabolism , Chlorocebus aethiops , Genotype , HEK293 Cells , HeLa Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lipid Droplets/metabolism , Membrane Proteins/genetics , Muscle Proteins/metabolism , Phenotype , Phosphatidylinositol Phosphates/metabolism , Proteolipids/metabolism , RNA Interference , Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics , Transfection
8.
Cell Mol Life Sci ; 81(1): 371, 2024 Aug 28.
Article in English | MEDLINE | ID: mdl-39196413

ABSTRACT

Current medical therapies for treating acute myeloid leukemia (AML) remain unmet, and AML patients may benefit from targeted immunotherapy approaches that focus on specific tumor antigens. GRP78, which is upregulated in various malignant tumors such as AML, is partially expressed as cell surface GRP78 (csGRP78) on the cell membrane, making it an ideal target for redirecting T cells, including T-cell engagers. However, considering the conventional approach of using two scFv segments to construct a bispecific T-cell engager (BiTE), we have undertaken the development of a novel BiTE that utilizes a cyclic peptide ligand to specifically target csGRP78, which we refer to as GRP78-CD3/BiTE. We studied the effects of GRP78-CD3/BiTE on treatments for AML in vitro and in vivo and assessed the pharmacokinetics of this engager. Our findings demonstrated that GRP78-CD3/BiTE could not only effectively mediate the cytotoxicity of T cells against csGRP78-expressing AML cells but also specifically eliminate primary AML tumor cells in vitro. Furthermore, GRP78-CD3/BiTE exhibited a longer half-life despite having a lower molecular weight than CD19-CD3/BiTE. In a xenograft mouse model of AML, treatment with GRP78-CD3/BiTE prolonged the survival time of the mice. Our findings demonstrate that GRP78-CD3/BiTE is effective and selective for eliminating csGRP78-expressing AML cells and suggest that this approach to targeted immunotherapy could lead to effective new treatments for AML.


Subject(s)
Antibodies, Bispecific , Endoplasmic Reticulum Chaperone BiP , Leukemia, Myeloid, Acute , T-Lymphocytes , Humans , Animals , Leukemia, Myeloid, Acute/immunology , Leukemia, Myeloid, Acute/therapy , Leukemia, Myeloid, Acute/pathology , Leukemia, Myeloid, Acute/drug therapy , Mice , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Antibodies, Bispecific/immunology , Antibodies, Bispecific/pharmacology , CD3 Complex/immunology , Heat-Shock Proteins/immunology , Heat-Shock Proteins/metabolism , Xenograft Model Antitumor Assays , Cell Line, Tumor , Ligands , Female , Mice, SCID , Immunotherapy/methods , Mice, Inbred NOD
9.
Nucleic Acids Res ; 51(17): 8987-9000, 2023 09 22.
Article in English | MEDLINE | ID: mdl-37534534

ABSTRACT

The generation of highly diverse antigen receptors in T and B lymphocytes relies on V(D)J recombination. The enhancer Eα has been implicated in regulating the accessibility of Vα and Jα genes through long-range interactions during rearrangements of the T-cell antigen receptor gene Tcra. However, direct evidence for Eα physically mediating the interaction of Vα and Jα genes is still lacking. In this study, we utilized the 3C-HTGTS assay, a chromatin interaction technique based on 3C, to analyze the higher order chromatin structure of the Tcra locus. Our analysis revealed the presence of sufficient information in the 3C-HTGTS data to detect multiway contacts. Three-way contact analysis of the Tcra locus demonstrated the co-occurrence of the proximal Jα genes, Vα genes and Eα in CD4+CD8+ double-positive thymocytes. Notably, the INT2-TEAp loop emerged as a prominent structure likely to be responsible for bringing the proximal Jα genes and the Vα genes into proximity. Moreover, the enhancer Eα utilizes this loop to establish physical proximity with the proximal Vα gene region. This study provides insights into the higher order chromatin structure of the Tcra locus, shedding light on the spatial organization of chromatin and its impact on V(D)J recombination.


Subject(s)
Receptors, Antigen, T-Cell, alpha-beta , Thymocytes , Chromatin/genetics , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell, alpha-beta/genetics , V(D)J Recombination/genetics , Animals , Mice
10.
Nucleic Acids Res ; 51(2): e12, 2023 01 25.
Article in English | MEDLINE | ID: mdl-36477375

ABSTRACT

The hub metabolite, nicotinamide adenine dinucleotide (NAD), can be used as an initiating nucleotide in RNA synthesis to result in NAD-capped RNAs (NAD-RNA). Since NAD has been heightened as one of the most essential modulators in aging and various age-related diseases, its attachment to RNA might indicate a yet-to-be discovered mechanism that impacts adult life-course. However, the unknown identity of NAD-linked RNAs in adult and aging tissues has hindered functional studies. Here, we introduce ONE-seq method to identify the RNA transcripts that contain NAD cap. ONE-seq has been optimized to use only one-step chemo-enzymatic biotinylation, followed by streptavidin capture and the nudix phosphohydrolase NudC-catalyzed elution, to specifically recover NAD-capped RNAs for epitranscriptome and gene-specific analyses. Using ONE-seq, we discover more than a thousand of previously unknown NAD-RNAs in the mouse liver and reveal epitranscriptome-wide dynamics of NAD-RNAs with age. ONE-seq empowers the identification of NAD-capped RNAs that are responsive to distinct physiological states, facilitating functional investigation into this modification.


Subject(s)
NAD , RNA Caps , Animals , Mice , NAD/genetics , NAD/metabolism , Nucleotides , Phosphoric Monoester Hydrolases , RNA Caps/genetics , Transcriptome , Epigenesis, Genetic
11.
BMC Bioinformatics ; 25(1): 35, 2024 Jan 23.
Article in English | MEDLINE | ID: mdl-38254030

ABSTRACT

BACKGROUND: Natural proteins occupy a small portion of the protein sequence space, whereas artificial proteins can explore a wider range of possibilities within the sequence space. However, specific requirements may not be met when generating sequences blindly. Research indicates that small proteins have notable advantages, including high stability, accurate resolution prediction, and facile specificity modification. RESULTS: This study involves the construction of a neural network model named TopoProGenerator(TPGen) using a transformer decoder. The model is trained with sequences consisting of a maximum of 65 amino acids. The training process of TopoProGenerator incorporates reinforcement learning and adversarial learning, for fine-tuning. Additionally, it encompasses a stability predictive model trained with a dataset comprising over 200,000 sequences. The results demonstrate that TopoProGenerator is capable of designing stable small protein sequences with specified topology structures. CONCLUSION: TPGen has the ability to generate protein sequences that fold into the specified topology, and the pretraining and fine-tuning methods proposed in this study can serve as a framework for designing various types of proteins.


Subject(s)
Amino Acids , Electric Power Supplies , Amino Acid Sequence , Language , Learning
12.
BMC Genomics ; 25(1): 133, 2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38302866

ABSTRACT

BACKGROUND: WD40 proteins, which are highly prevalent in eukaryotes, play important roles in plant development and stress responses. However, systematic identification and exploration of WD40 proteins in tobacco have not yet been conducted. RESULTS: In this study, a total of 399 WD40 regulatory genes were identified in common tobacco (Nicotiana tabacum). Gene structure and motif analysis revealed structural and functional diversity among different clades of tobacco WD40 regulatory genes. The expansion of tobacco WD40 regulatory genes was mainly driven by segmental duplication and purifying selection. A potential regulatory network of NtWD40s suggested that NtWD40s might be regulated by miRNAs and transcription factors in various biological processes. Expression pattern analysis via transcriptome analysis and qRT-PCR revealed that many NtWD40s exhibited tissue-specific expression patterns and might be involved in various biotic and abiotic stresses. Furthermore, we have validated the critical role of NtTTG1, which was located in the nuclei of trichome cells, in enhancing the drought tolerance of tobacco plants. CONCLUSIONS: Our study provides comprehensive information to better understand the evolution of WD40 regulatory genes and their roles in different stress responses in tobacco.


Subject(s)
Drought Resistance , Nicotiana , Nicotiana/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Transcription Factors/metabolism , Gene Expression Profiling , Stress, Physiological/genetics , Gene Expression Regulation, Plant , Phylogeny
13.
Biochem Biophys Res Commun ; 734: 150661, 2024 Nov 19.
Article in English | MEDLINE | ID: mdl-39243675

ABSTRACT

Hematopoietic stem progenitor cells (HSPCs) give rise to the hematopoietic system, maintain hematopoiesis throughout the lifespan, and undergo molecular and functional changes during their development and aging. The importance of hematopoietic stem cell (HSC) biology has led to their extensive characterization at genomic and transcriptomic levels. However, the proteomics of HSPCs throughout the murine lifetime still needs to be fully completed. Here, using mass spectrometry (MS)-based quantitative proteomics, we report on the dynamic changes in the proteome of HSPCs from four developmental stages in the fetal liver (FL) and the bone marrow (BM), including E14.5, young (2 months), middle-aged (8 months), and aging (18 months) stages. Proteomics unveils highly dynamic protein kinetics during the development and aging of HSPCs. Our data identify stage-specific developmental features of HSPCs, which can be linked to their functional maturation and senescence. Our proteomic data demonstrated that FL HSPCs depend on aerobic respiration to meet their proliferation and oxygen supply demand, while adult HSPCs prefer glycolysis to preserve the HSC pool. By functional assays, we validated the decreased mitochondrial metabolism, glucose uptake, reactive oxygen species (ROS) production, protein synthesis rate, and increased glutathione S-transferase (GST) activity during HSPC development from fetal to adult. Distinct metabolism pathways and immune-related pathways enriched in different HSPC developmental stages were revealed at the protein level. Our study will have broader implications for understanding the mechanism of stem cell maintenance and fate determination and reversing the HSC aging process.


Subject(s)
Hematopoietic Stem Cells , Mice, Inbred C57BL , Proteomics , Animals , Hematopoietic Stem Cells/metabolism , Hematopoietic Stem Cells/cytology , Proteomics/methods , Mice , Metabolic Networks and Pathways , Proteome/metabolism , Reactive Oxygen Species/metabolism , Fetus/metabolism , Fetus/cytology , Cellular Senescence , Mitochondria/metabolism , Liver/metabolism , Liver/embryology , Liver/cytology
14.
BMC Plant Biol ; 24(1): 134, 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38403644

ABSTRACT

BACKGROUND: N6-methyladenosine (m6A) is one of the common internal RNA modifications found in eukaryotes. The m6A modification can regulate various biological processes in organisms through the modulation of alternative splicing, alternative polyadenylation, folding, translation, localization, transport, and decay of multiple types of RNA, without altering the nucleotide sequence. The three components involved in m6A modification, namely writer, eraser, and reader, mediate the abundance of RNA m6A modification through complex collaborative actions. Currently, research on m6A regulatory genes in plants is still in its infancy. RESULTS: In this study, we identified 52 candidate m6A regulatory genes in common tobacco (Nicotiana tabacum L.). Gene structure, conserved domains, and motif analysis showed structural and functional diversity among different subgroups of tobacco m6A regulatory genes. The amplification of m6A regulatory genes were mainly driven by polyploidization and dispersed duplication, and duplicated genes evolved through purified selection. Based on the potential regulatory network and expression pattern analysis of m6A regulatory genes, a significant number of m6A regulatory genes might play important roles in growth, development, and stress response processes. Furthermore, we have confirmed the critical role of NtFIP37B, an m6A writer gene in tobacco, in enhancing drought resistance. CONCLUSIONS: This study provides useful information for better understanding the evolution of m6A regulatory genes and the role of m6A modification in tobacco stress response, and lays the foundation for further elucidating the function of m6A regulatory genes in tobacco.


Subject(s)
Adenosine/analogs & derivatives , Drought Resistance , Nicotiana , Nicotiana/genetics , Genes, Regulator , RNA , Gene Expression Regulation, Plant , Stress, Physiological/genetics , Phylogeny
15.
BMC Plant Biol ; 24(1): 854, 2024 Sep 12.
Article in English | MEDLINE | ID: mdl-39266948

ABSTRACT

Casuarina equisetifolia trees are used as windbreaks in subtropical and tropical coastal zones, while C. equisetifolia windbreak forests can be degraded by seawater atomization (SA) and seawater encroachment (SE). To investigate the mechanisms underlying the response of C. equisetifolia to SA and SE stress, the transcriptome and metabolome of C. equisetifolia seedlings treated with control, SA, and SE treatments were analyzed. We identified 737, 3232, 3138, and 3899 differentially expressed genes (SA and SE for 2 and 24 h), and 46, 66, 62, and 65 differentially accumulated metabolites (SA and SE for 12 and 24 h). The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that SA and SE stress significantly altered the expression of genes related to plant hormone signal transduction, plant-pathogen interaction, and starch and sucrose metabolism pathways. The accumulation of metabolites associated with the biosynthetic pathways of phenylpropanoid and amino acids, as well as starch and sucrose metabolism, and glycolysis/gluconeogenesis were significantly altered in C. equisetifolia subjected to SA and SE stress. In conclusion, C. equisetifolia responds to SA and SE stress by regulating plant hormone signal transduction, plant-pathogen interaction, biosynthesis of phenylpropanoid and amino acids, starch and sucrose metabolism, and glycolysis/gluconeogenesis pathways. Compared with SA stress, C. equisetifolia had a stronger perception and response to SE stress, which required more genes and metabolites to be regulated. This study enhances our understandings of how C. equisetifolia responds to two types of seawater stresses at transcriptional and metabolic levels. It also offers a theoretical framework for effective coastal vegetation management in tropical and subtropical regions.


Subject(s)
Seawater , Stress, Physiological , Stress, Physiological/genetics , Seawater/chemistry , Transcriptome , Gene Expression Regulation, Plant , Metabolome , Seedlings/genetics , Seedlings/physiology , Metabolomics , Multiomics
16.
Plant Physiol ; 193(2): 1281-1296, 2023 09 22.
Article in English | MEDLINE | ID: mdl-37394939

ABSTRACT

Introns are noncoding sequences spliced out of pre-mRNAs by the spliceosome to produce mature mRNAs. The 5' ends of introns mostly begin with GU and have a conserved sequence motif of AG/GUAAGU that could base-pair with the core sequence of U1 snRNA of the spliceosome. Intriguingly, ∼ 1% of introns in various eukaryotic species begin with GC. This occurrence could cause misannotation of genes; however, the underlying splicing mechanism is unclear. We analyzed the sequences around the intron 5' splice site (ss) in Arabidopsis (Arabidopsis thaliana) and found sequences at the GC intron ss are much more stringent than those of GT introns. Mutational analysis at various positions of the intron 5' ss revealed that although mutations impair base pairing, different mutations at the same site can have different effects, suggesting that steric hindrance also affects splicing. Moreover, mutations of 5' ss often activate a hidden ss nearby. Our data suggest that the 5' ss is selected via a competition between the major ss and the nearby minor ss. This work not only provides insights into the splicing mechanism of intron 5' ss but also improves the accuracy of gene annotation and the study of the evolution of intron 5' ss.


Subject(s)
RNA Splice Sites , RNA Splicing , Introns/genetics , RNA Splice Sites/genetics , Base Sequence , RNA Splicing/genetics , RNA Precursors/genetics
17.
Blood ; 139(16): 2534-2546, 2022 04 21.
Article in English | MEDLINE | ID: mdl-35030251

ABSTRACT

Master regulators, such as the hematopoietic transcription factor (TF) GATA1, play an essential role in orchestrating lineage commitment and differentiation. However, the precise mechanisms by which such TFs regulate transcription through interactions with specific cis-regulatory elements remain incompletely understood. Here, we describe a form of congenital hemolytic anemia caused by missense mutations in an intrinsically disordered region of GATA1, with a poorly understood role in transcriptional regulation. Through integrative functional approaches, we demonstrate that these mutations perturb GATA1 transcriptional activity by partially impairing nuclear localization and selectively altering precise chromatin occupancy by GATA1. These alterations in chromatin occupancy and concordant chromatin accessibility changes alter faithful gene expression, with failure to both effectively silence and activate select genes necessary for effective terminal red cell production. We demonstrate how disease-causing mutations can reveal regulatory mechanisms that enable the faithful genomic targeting of master TFs during cellular differentiation.


Subject(s)
Anemia , GATA1 Transcription Factor , Cell Differentiation/genetics , Chromatin/genetics , Chromatin Immunoprecipitation , Erythropoiesis/genetics , GATA1 Transcription Factor/genetics , GATA1 Transcription Factor/metabolism , Humans
18.
J Biol Inorg Chem ; 29(3): 315-330, 2024 04.
Article in English | MEDLINE | ID: mdl-38722397

ABSTRACT

Eighteen novel Ti(IV) complexes stabilized by different chelating amino-bis(phenolato) (ONNO, ONON, ONOO) ligands and 2,6-dipicolinic acid as a second chelator were synthesized with isolated yields ranging from 79 to 93%. Complexes were characterized by 1H and 13C-NMR spectroscopy, as well as by HRMS and X-Ray diffraction analysis. The good to excellent aqueous stability of these Ti(IV) complexes can be modulated by the substitutions on the 2-position of the phenolato ligands. Most of the synthesized Ti(IV) complexes demonstrated potent inhibitory activity against Hela S3 and Hep G2 tumor cells. Among them, the naphthalenyl based Salan type 2j, 2-picolylamine based [ONON] type 2n and N-(2-hydroxyethyl) based [ONOO] type 2p demonstrated up to 40 folds enhanced cytotoxicity compared to cisplatin together with a significantly reduced activity against healthy AML12 cells. The three Ti(IV) complexes exhibited fast cellular uptake by Hela S3 cells and induced almost exclusively apoptosis. 2j could trigger higher level of ROS generation than 2p and 2n.


Subject(s)
Antineoplastic Agents , Coordination Complexes , Drug Screening Assays, Antitumor , Picolinic Acids , Titanium , Humans , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/chemical synthesis , Picolinic Acids/chemistry , Picolinic Acids/pharmacology , Picolinic Acids/chemical synthesis , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Coordination Complexes/chemical synthesis , Structure-Activity Relationship , Titanium/chemistry , Titanium/pharmacology , HeLa Cells , Apoptosis/drug effects , Molecular Structure , Cell Proliferation/drug effects
19.
Diabetes Metab Res Rev ; 40(2): e3733, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37823338

ABSTRACT

The pathogenesis of diabetes is accompanied by increased levels of inflammatory factors, also known as "metabolic inflammation", which runs through the whole process of the occurrence and development of the disease. Mitochondria, as the key site of glucose and lipid metabolism, is often accompanied by mitochondrial function damage in type 2 diabetes mellitus (T2DM). Damaged mitochondria release pro-inflammatory factors through damage-related molecular patterns that activate inflammation pathways and reactions to oxidative stress, further aggravate metabolic disorders, and form a vicious circle. Currently, the pathogenesis of diabetes is still unclear, and clinical treatment focuses primarily on symptomatic intervention of the internal environment of disorders of glucose and lipid metabolism with limited clinical efficacy. The proinflammatory effect of mitochondrial damage-associated molecular pattern (mtDAMP) in T2DM provides a new research direction for exploring the pathogenesis and intervention targets of T2DM. Therefore, this review covers the most recent findings on the molecular mechanism and related signalling cascades of inflammation caused by mtDAMP in T2DM and discusses its pathogenic role of it in the pathological process of T2DM to search potential intervention targets.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Humans , Diabetes Mellitus, Type 2/drug therapy , Mitochondria/metabolism , Mitochondria/pathology , Inflammation/metabolism , Glucose/metabolism , Signal Transduction
20.
Eur J Nucl Med Mol Imaging ; 51(6): 1685-1697, 2024 May.
Article in English | MEDLINE | ID: mdl-38246909

ABSTRACT

Due to the heterogeneity of tumors, strategies to improve the effectiveness of dual-targeting tracers in tumor diagnostics have been intensively practiced. In this study, the radiolabeled [18F]AlF-NOTA-FAPI-RGD (denoted as [18F]AlF-LNC1007), a dual-targeting heterodimer tracer targeting both fibroblast activation protein (FAP) and integrin αvß3 to enhance specific tumor uptake and retention, was synthesized and evaluated. The tracer was compared with [68Ga]Ga-LNC1007 in preclinical and clinical settings. METHODS: The preparation of [18F]AlF- and 68Ga-labeled FAPI-RGD was carried out with an optimized protocol. The stability was tested in PBS and fetal bovine serum (FBS). Cellular uptake and in vivo distribution of the two products were compared and carried out on the U87MG cell line and its xenograft model. The safety and dosimetry of [18F]AlF-LNC1007 PET/CT scan were evaluated in six patients with malignant tumors. RESULTS: Two radiolabeling protocols of [18F]AlF-/[68Ga]Ga-LNC1007 were developed and optimized to give a high yield of tracers with good stability. In vivo microPET images showed that the two tracers exhibited comparable pharmacokinetic characteristics, with high tumor uptake and prolonged tumor retention. In vivo distribution data showed that the target-to-non-target ratios of [18F]AlF-LNC1007 were similar to[68Ga]Ga-LNC1007. A total of six patients underwent [18F]AlF-LNC1007 PET/CT evaluation while two had head-to-head [18F]FDG PET/CT scans. The total body effective dose was 9.94E-03 mSv/MBq. The biodistribution curve showed optimal normal organ uptake with high tumor uptake and long retention of up to 3h p.i., and notably, the tumor-to-background ratio increased over time. CONCLUSION: We successfully prepared an [18F]AlF-LNC1007 dual-targeting PET probe with comparable performances as [68Ga]Ga-LNC1007. With prolonged tumor retention and tumor specificity, it produced good imaging quality in preclinical and clinical translational studies, indicating that [18F]AlF-LNC1007 is a promising non-invasive tracer for detecting tumors expressing FAP and/or integrin avß3, with the prospect of clinical implementation.


Subject(s)
Aluminum Compounds , Endopeptidases , Fluorides , Fluorine Radioisotopes , Membrane Proteins , Oligopeptides , Positron Emission Tomography Computed Tomography , Positron Emission Tomography Computed Tomography/methods , Humans , Animals , Mice , Fluorine Radioisotopes/chemistry , Cell Line, Tumor , Oligopeptides/chemistry , Oligopeptides/pharmacokinetics , Female , Tissue Distribution , Gallium Radioisotopes , Pilot Projects , Male , Isotope Labeling , Neoplasms/diagnostic imaging , Middle Aged , Radiopharmaceuticals/pharmacokinetics , Radiopharmaceuticals/chemistry
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