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1.
Cell ; 186(17): 3577-3592.e18, 2023 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-37499659

RESUMEN

Hybrid sterility restricts the utilization of superior heterosis of indica-japonica inter-subspecific hybrids. In this study, we report the identification of RHS12, a major locus controlling male gamete sterility in indica-japonica hybrid rice. We show that RHS12 consists of two genes (iORF3/DUYAO and iORF4/JIEYAO) that confer preferential transmission of the RHS12-i type male gamete into the progeny, thereby forming a natural gene drive. DUYAO encodes a mitochondrion-targeted protein that interacts with OsCOX11 to trigger cytotoxicity and cell death, whereas JIEYAO encodes a protein that reroutes DUYAO to the autophagosome for degradation via direct physical interaction, thereby detoxifying DUYAO. Evolutionary trajectory analysis reveals that this system likely formed de novo in the AA genome Oryza clade and contributed to reproductive isolation (RI) between different lineages of rice. Our combined results provide mechanistic insights into the genetic basis of RI as well as insights for strategic designs of hybrid rice breeding.


Asunto(s)
Tecnología de Genética Dirigida , Oryza , Hibridación Genética , Oryza/genética , Fitomejoramiento/métodos , Aislamiento Reproductivo , Infertilidad Vegetal
2.
Cell ; 184(5): 1377-1391.e14, 2021 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-33545088

RESUMEN

Rich fossil evidence suggests that many traits and functions related to terrestrial evolution were present long before the ancestor of lobe- and ray-finned fishes. Here, we present genome sequences of the bichir, paddlefish, bowfin, and alligator gar, covering all major early divergent lineages of ray-finned fishes. Our analyses show that these species exhibit many mosaic genomic features of lobe- and ray-finned fishes. In particular, many regulatory elements for limb development are present in these fishes, supporting the hypothesis that the relevant ancestral regulation networks emerged before the origin of tetrapods. Transcriptome analyses confirm the homology between the lung and swim bladder and reveal the presence of functional lung-related genes in early ray-finned fishes. Furthermore, we functionally validate the essential role of a jawed vertebrate highly conserved element for cardiovascular development. Our results imply the ancestors of jawed vertebrates already had the potential gene networks for cardio-respiratory systems supporting air breathing.


Asunto(s)
Evolución Biológica , Peces/genética , Aletas de Animales/fisiología , Animales , Fenómenos Fisiológicos Cardiovasculares , Sistema Cardiovascular/anatomía & histología , Extremidades/fisiología , Peces/clasificación , Genoma , Pulmón/anatomía & histología , Pulmón/fisiología , Filogenia , Receptores Odorantes/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcriptoma , Vertebrados/clasificación , Vertebrados/genética
3.
Cell ; 182(5): 1328-1340.e13, 2020 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-32814014

RESUMEN

Among arthropod vectors, ticks transmit the most diverse human and animal pathogens, leading to an increasing number of new challenges worldwide. Here we sequenced and assembled high-quality genomes of six ixodid tick species and further resequenced 678 tick specimens to understand three key aspects of ticks: genetic diversity, population structure, and pathogen distribution. We explored the genetic basis common to ticks, including heme and hemoglobin digestion, iron metabolism, and reactive oxygen species, and unveiled for the first time that genetic structure and pathogen composition in different tick species are mainly shaped by ecological and geographic factors. We further identified species-specific determinants associated with different host ranges, life cycles, and distributions. The findings of this study are an invaluable resource for research and control of ticks and tick-borne diseases.


Asunto(s)
Variación Genética/genética , Enfermedades por Picaduras de Garrapatas/microbiología , Garrapatas/genética , Animales , Línea Celular , Vectores de Enfermedades , Especificidad del Huésped/genética
4.
Nature ; 604(7907): 723-731, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35418686

RESUMEN

Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell-cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.


Asunto(s)
Macaca fascicularis , Transcriptoma , Animales , Comunicación Celular , Macaca fascicularis/genética , Receptores Virales/genética , Transcriptoma/genética , Vía de Señalización Wnt
5.
Plant J ; 117(1): 92-106, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37738394

RESUMEN

Root hairs are crucial in the uptake of essential nutrients and water in plants. This study showed that a zinc finger protein, GIS3 is involved in root hair growth in Arabidopsis. The loss-of-function gis3 and GIS3 RNAi transgenic line exhibited a significant reduction in root hairs compared to the wild type. The application of 1-aminocyclopropane-1-carboxylic acid (ACC), an exogenous ethylene precursor, and 6-benzyl amino purine (BA), a synthetic cytokinin, significantly restored the percentage of hair cells in the epidermis in gis3 and induced GIS3 expression in the wild type. More importantly, molecular and genetic studies revealed that GIS3 acts upstream of ROOT HAIR DEFECTIVE 2 (RHD2) and RHD4 by binding to their promoters. Furthermore, exogenous ACC and BA application significantly induced the expression of RHD2 and RHD4, while root hair phenotype of rhd2-1, rhd4-1, and rhd4-3 was insensitive to ACC and BA treatment. We can therefore conclude that GIS3 modulates root hair development by directly regulating RHD2 and RHD4 expression through ethylene and cytokinin signals in Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Inflorescencia/metabolismo , Etilenos/metabolismo , Citocininas/metabolismo , Raíces de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Mutación
6.
Trends Genet ; 38(5): 416-418, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35181164

RESUMEN

Centromeres have an essential and conserved role in eukaryotes, and represent a paradoxical feature of rapid evolution. A recent study by Naish et al. applied long-read sequencing to survey a genome assembly of all five Arabidopsis (Arabidopsisthaliana) centromeres. Analyses of these centromeres showed characteristic genetic and epigenetic features, providing new insights into centromere evolution.


Asunto(s)
Arabidopsis , Arabidopsis/genética , Centrómero/genética , Histonas/genética
7.
Gastroenterology ; 166(4): 605-619, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38176660

RESUMEN

BACKGROUND & AIMS: We aimed to assess the secular trend of the global prevalence of Helicobacter pylori (H pylori) infection in adults and children/adolescents and to show its relation to that of gastric cancer incidence. METHODS: We performed a systematic review and meta-analysis to calculate overall prevalence, adjusted by multivariate meta-regression analysis. The incidence rates of gastric cancer were derived from the Global Burden of Disease Study and Cancer Incidence in Five Continents. RESULTS: Of the 16,976 articles screened, 1748 articles from 111 countries were eligible for analysis. The crude global prevalence of H pylori has reduced from 52.6% (95% confidence interval [CI], 49.6%-55.6%) before 1990 to 43.9% (95% CI, 42.3%-45.5%) in adults during 2015 through 2022, but was as still as high as 35.1% (95% CI, 30.5%-40.1%) in children and adolescents during 2015 through 2022. Secular trend and multivariate regression analyses showed that the global prevalence of H pylori has declined by 15.9% (95% CI, -20.5% to -11.3%) over the last 3 decades in adults, but not in children and adolescents. Significant reduction of H pylori prevalence was observed in adults in the Western Pacific, Southeast Asian, and African regions. However, H pylori prevalence was not significantly reduced in children and adolescents in any World Health Organization regions. The incidence of gastric cancer has decreased globally and in various countries where the prevalence of H pylori infection has declined. CONCLUSIONS: The global prevalence of H pylori infection has declined during the last 3 decades in adults, but not in children and adolescents. The results raised the hypothesis that the public health drive to reduce the prevalence of H pylori as a strategy to reduce the incidence of gastric cancer in the population should be confirmed in large-scale clinical trials.


Asunto(s)
Infecciones por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Adulto , Niño , Adolescente , Humanos , Incidencia , Neoplasias Gástricas/epidemiología , Neoplasias Gástricas/etiología , Infecciones por Helicobacter/tratamiento farmacológico , Prevalencia
8.
Plant Cell ; 34(7): 2730-2746, 2022 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-35435232

RESUMEN

Glycogen synthase kinase 3 (GSK3) family members serve as signaling hubs for plant development and stress responses, yet the underlying mechanism of their transcriptional regulation remains a long-standing mystery. Here we show that the transcription of SHAGGY-like kinase 11/12 (SK11/12), two members of the GSK3 gene family, is promoted by the splicing factor SmD1b, which is essential for distributing carbon sources into storage and protective components in Arabidopsis seeds. The chromatin recruitment of SmD1b at the SK11/12 loci promotes their transcription associated with co-transcriptional splicing of the first introns in the 5'-untranslated region of SK11/12. The loss of SmD1b function generates transcripts with unspliced introns that create disruptive R-loops to hamper the transcriptional elongation of SK11/12, in addition to compromising the recruitment of RNA polymerase II to the SK11/12 genomic regions. These effects imposed by SmD1b determine the transcription of SK11/12 to confer a key switch of carbon flow among metabolic pathways in zygotic and maternal tissues in seeds.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Carbono/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Semillas/genética , Semillas/metabolismo
9.
Plant Cell ; 34(10): 3632-3646, 2022 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-35762970

RESUMEN

Rice (Oryza sativa) is one of the most important crops worldwide. Heading date is a vital agronomic trait that influences rice yield and adaption to local conditions. Hd3a, a proposed florigen that primarily functions under short-day (SD) conditions, is a mobile flowering signal that promotes the floral transition in rice. Nonetheless, how Hd3a is transported from leaves to the shoot apical meristem (SAM) under SDs remains elusive. Here, we report that FT-INTERACTING PROTEIN9 (OsFTIP9) specifically regulates rice flowering time under SDs by facilitating Hd3a transport from companion cells (CCs) to sieve elements (SEs). Furthermore, we show that the tetratricopeptide repeat (TPR) protein OsTPR075 interacts with both OsFTIP9 and OsFTIP1 and strengthens their respective interactions with Hd3a and the florigen RICE FLOWERING LOCUS T1 (RFT1). This in turn affects the trafficking of Hd3a and RFT1 to the SAM, thus regulating flowering time under SDs and long-day conditions, respectively. Our findings suggest that florigen transport in rice is mediated by different OsFTIPs under different photoperiods and those interactions between OsTPR075 and OsFTIPs are essential for mediating florigen movement from leaves to the SAM.


Asunto(s)
Florigena , Oryza , Florigena/metabolismo , Flores/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Oryza/metabolismo , Fotoperiodo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Repeticiones de Tetratricopéptidos
10.
Mol Psychiatry ; 2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38336841

RESUMEN

Antipsychotic-induced weight gain (AIWG) is a common side effect of antipsychotic medication and may contribute to diabetes and coronary heart disease. To expand the unclear genetic mechanism underlying AIWG, we conducted a two-stage genome-wide association study in Han Chinese patients with schizophrenia. The study included a discovery cohort of 1936 patients and a validation cohort of 534 patients, with an additional 630 multi-ancestry patients from the CATIE study for external validation. We applied Mendelian randomization (MR) analysis to investigate the relationship between AIWG and antipsychotic-induced lipid changes. Our results identified two novel genome-wide significant loci associated with AIWG: rs10422861 in PEPD (P = 1.373 × 10-9) and rs3824417 in PTPRD (P = 3.348 × 10-9) in Chinese Han samples. The association of rs10422861 was validated in the European samples. Fine-mapping and functional annotation revealed that PEPD and PTPRD are potentially causal genes for AIWG, with their proteins being prospective therapeutic targets. Colocalization analysis suggested that AIWG and type 2 diabetes (T2D) shared a causal variant in PEPD. Polygenic risk scores (PRSs) for AIWG and T2D significantly predicted AIWG in multi-ancestry samples. Furthermore, MR revealed a risky causal effect of genetically predicted changes in low-density lipoprotein cholesterol (P = 7.58 × 10-4) and triglycerides (P = 2.06 × 10-3) caused by acute-phase of antipsychotic treatment on AIWG, which had not been previously reported. Our model, incorporating antipsychotic-induced lipid changes, PRSs, and clinical predictors, significantly predicted BMI percentage change after 6-month antipsychotic treatment (AUC = 0.79, R2 = 0.332). Our results highlight that the mechanism of AIWG involves lipid pathway dysfunction and may share a genetic basis with T2D through PEPD. Overall, this study provides new insights into the pathogenesis of AIWG and contributes to personalized treatment of schizophrenia.

11.
Methods ; 222: 51-56, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38184219

RESUMEN

The interaction between human microbes and drugs can significantly impact human physiological functions. It is crucial to identify potential microbe-drug associations (MDAs) before drug administration. However, conventional biological experiments to predict MDAs are plagued by drawbacks such as time-consuming, high costs, and potential risks. On the contrary, computational approaches can speed up the screening of MDAs at a low cost. Most computational models usually use a drug similarity matrix as the initial feature representation of drugs and stack the graph neural network layers to extract the features of network nodes. However, different calculation methods result in distinct similarity matrices, and message passing in graph neural networks (GNNs) induces phenomena of over-smoothing and over-squashing, thereby impacting the performance of the model. To address these issues, we proposed a novel graph representation learning model, dual-modal graph learning for microbe-drug association prediction (DMGL-MDA). It comprises a dual-modal embedding module, a bipartite graph network embedding module, and a predictor module. To assess the performance of DMGL-MDA, we compared it against state-of-the-art methods using two benchmark datasets. Through cross-validation, we illustrated the superiority of DMGL-MDA. Furthermore, we conducted ablation experiments and case studies to validate the effective performance of the model.


Asunto(s)
Benchmarking , Redes Neurales de la Computación , Humanos , Proyectos de Investigación
12.
Brain ; 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38701344

RESUMEN

The implication of 5-hydroxytryptamine 2C receptor (5-HT2CR) in depression is a topic of debate, and the underlying mechanisms remain largely unclear. We now elucidate hippocampal excitation-inhibition (E/I) balance underlies the regulatory effects of 5-HT2CR in depression. Molecular biological analyses showed that chronic mild stress (CMS) reduced the expression of 5-HT2CR in hippocampus. We revealed that inhibition of 5-HT2CR induced depressive-like behaviors, reduced GABA release and shifted the E/I balance towards excitation in CA3 pyramidal neurons by using behavioral analyses, microdialysis coupled with mass spectrum, and electrophysiological recording. Moreover, 5-HT2CR modulated neuronal nitric oxide synthase (nNOS)-carboxy-terminal PDZ ligand of nNOS (CAPON) interaction through influencing intracellular Ca2+ release, as determined by fiber photometry and coimmunoprecipitation. Notably, disruption of nNOS-CAPON by specific small molecule compound ZLc-002 or AAV-CMV-CAPON-125C-GFP, abolished 5-HT2CR inhibition-induced depressive-like behaviors, as well as the impairment in soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly-mediated GABA vesicle release and a consequent E/I imbalance. Importantly, optogenetic inhibition of CA3 GABAergic neurons prevented the effects of AAV-CMV-CAPON-125C-GFP on depressive behaviors in the presence of 5-HT2CR antagonist. Conclusively, our findings disclose the regulatory role of 5-HT2CR in depressive-like behaviors and highlight the hippocampal nNOS-CAPON coupling-triggered E/I imbalance as a pivotal cellular event underpinning the behavioral consequences of 5-HT2CR inhibition.

13.
Nucleic Acids Res ; 51(14): 7666-7674, 2023 08 11.
Artículo en Inglés | MEDLINE | ID: mdl-37351632

RESUMEN

The 26-mer DNA aptamer (AF26) that specifically binds aflatoxin B1 (AFB1) with nM-level high affinity is rare among hundreds of aptamers for small molecules. Despite its predicted stem-loop structure, the molecular basis of its high-affinity recognition of AFB1 remains unknown. Here, we present the first high-resolution nuclear magnetic resonance structure of AFB1-AF26 aptamer complex in solution. AFB1 binds to the 16-residue loop region of the aptamer, inducing it to fold into a compact structure through the assembly of two bulges and one hairpin structure. AFB1 is tightly enclosed within a cavity formed by the bulges and hairpin, held in a place between the G·C base pair, G·G·C triple and multiple T bases, mainly through strong π-π stacking, hydrophobic and donor atom-π interactions, respectively. We further revealed the mechanism of the aptamer in recognizing AFB1 and its analogue AFG1 with only one-atom difference and introduced a single base mutation at the binding site of the aptamer to increase the discrimination between AFB1 and AFG1 based on the structural insights. This research provides an important structural basis for understanding high-affinity recognition of the aptamer, and for further aptamer engineering, modification and applications.


Asunto(s)
Aflatoxina B1 , Aptámeros de Nucleótidos , Aflatoxina B1/química , Aflatoxina B1/metabolismo , Aptámeros de Nucleótidos/química , Aptámeros de Nucleótidos/metabolismo , Técnicas Biosensibles , Límite de Detección
14.
Drug Resist Updat ; 73: 101052, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38262246

RESUMEN

AIMS: This investigation aims to elucidate the mechanism underlying sorafenib-induced ferroptosis in hepatocellular carcinoma (HCC). METHODS: The role of dual specificity phosphatase 4 (DUSP4) in sorafenib-treated HCC was investigated using comprehensive assessments both in vitro and in vivo, including Western blotting, qRT-PCR, cell viability assay, lipid reactive oxygen species (ROS) assay, immunohistochemistry, and xenograft tumor mouse model. Additionally, label-free quantitative proteomics was employed to identify potential proteins associated with DUSP4. RESULTS: Our study revealed that suppression of DUSP4 expression heightens the susceptibility of HCC cells to ferroptosis inducers, specifically sorafenib and erastin, in both in vitro and in vivo settings. Furthermore, we identified DUSP4-mediated regulation of key ferroptosis-related markers, such as ferritin light chain (FTL) and ferritin heavy chain 1 (FTH1). Notably, label-free quantitative proteomics unveiled the phosphorylation of threonine residue T148 on YTH Domain Containing 1 (YTHDC1) by DUSP4. Further investigations unraveled that YTHDC1, functioning as an mRNA nuclear export regulator, is a direct target of DUSP4, orchestrating the subcellular localization of FTL and FTH1 mRNAs. Significantly, our study highlights a strong correlation between elevated DUSP4 expression and sorafenib resistance in HCC. CONCLUSIONS: Our findings introduce DUSP4 as a negative regulator of sorafenib-induced ferroptosis. This discovery opens new avenues for the development of ferroptosis-based therapeutic strategies tailored for HCC treatment.


Asunto(s)
Carcinoma Hepatocelular , Ferroptosis , Neoplasias Hepáticas , Humanos , Animales , Ratones , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/genética , Sorafenib/farmacología , Sorafenib/uso terapéutico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Monoéster Fosfórico Hidrolasas/uso terapéutico , Ferroptosis/genética , Línea Celular Tumoral
15.
Nano Lett ; 24(9): 2689-2697, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38285690

RESUMEN

Simulating the behavior of metal nanoparticles on supports is crucial for boosting their catalytic performance and various nanotechnology applications; however, such simulations are limited by the conflicts between accuracy and efficiency. Herein, we introduce a multiscale modeling strategy to unveil the morphology of Ru supported on pristine and N-doped graphene. Our multiscale modeling started with the electronic structures of a supported Ru single atom, revealing the strong metal-support interaction around pyridinic nitrogen sites. To determine the stable configurations of Ru2-13 clusters on three different graphene supports, global energy minimum searches were performed. The sintering of the global minimum Ru13 clusters on supports was further simulated by ab initio molecular dynamics (AIMD). The AIMD data set was then collected for deep potential molecular dynamics to study the melting of Ru nanoparticles. This study presents comprehensive descriptions of carbon-supported Ru and develops modeling approaches that bridge different scales and can be applied to various supported nanoparticle systems.

16.
Nano Lett ; 24(2): 649-656, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38165119

RESUMEN

Recent theoretical and experimental studies of the interlayer Dzyaloshinskii-Moriya interaction (DMI) have sparked great interest in its implementation into practical magnetic random-access memory (MRAM) devices, due to its capability to mediate long-range chiral spin textures. So far, experimental reports focused on the observation of interlayer DMI, leaving the development of strategies to control interlayer DMI's magnitude unaddressed. Here, we introduce an azimuthal symmetry engineering protocol capable of additive/subtractive tuning of interlayer DMI through the control of wedge deposition of separate layers and demonstrate its capability to mediate field-free spin-orbit torque (SOT) magnetization switching in both orthogonally magnetized and synthetic antiferromagnetically coupled systems. Furthermore, we showcase that the spatial inhomogeneity brought about by wedge deposition can be suppressed by specific azimuthal engineering design, ideal for practical implementation. Our findings provide guidelines for effective manipulations of interlayer DMI strength, beneficial for the future design of SOT-MRAM or other spintronic devices utilizing interlayer DMI.

17.
Nano Lett ; 24(11): 3448-3455, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38452056

RESUMEN

Unlike graphene derived from graphite, borophenes represent a distinct class of synthetic two-dimensional materials devoid of analogous bulk-layered allotropes, leading to covalent bonding within borophenes instead of van der Waals (vdW) stacking. Our investigation focuses on 665 vdW-stacking boron bilayers to uncover potential bulk-layered boron allotropes through vdW stacking. Systematic high-throughput screening and stability analysis reveal a prevailing inclination toward covalently bonded layers in the majority of boron bilayers. However, an intriguing outlier emerges in δ5 borophene, demonstrating potential as a vdW-stacking candidate. We delve into electronic and topological structural similarities between δ5 borophene and graphene, shedding light on the structural integrity and stability of vdW-stacked boron structures across bilayers, multilayers, and bulk-layered allotropes. The δ5 borophene analogues exhibit metallic properties and characteristics of phonon-mediated superconductors, boasting a critical temperature near 22 K. This study paves the way for the concept of "borophite", a long-awaited boron analogue of graphite.

18.
Plant J ; 116(5): 1234-1247, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37565662

RESUMEN

Success in plant reproduction is highly dependent on the correct timing of the floral transition, which is tightly regulated by the flowering pathways. In the model plant Arabidopsis thaliana, the central flowering repressor FLOWERING LOCUS C (FLC) is precisely regulated by multiple flowering time regulators in the vernalization pathway and autonomous pathway, including FPA. Here we report that Arabidopsis MEDIATOR SUBUNIT 8 (MED8) promotes floral transition in Arabidopsis by recruiting FPA to the FLC locus to repress FLC expression. Loss of MED8 function leads to a significant late-flowering phenotype due to increased FLC expression. We further show that MED8 directly interacts with FPA in the nucleus and recruits FPA to the FLC locus. Moreover, MED8 is indispensable for FPA's function in controlling flowering time and regulating FLC expression. Our study thus reveals a flowering mechanism by which the Mediator subunit MED8 represses FLC expression by facilitating the binding of FPA to the FLC locus to ensure appropriate timing of flowering for reproductive success.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Flores/fisiología , Regulación de la Expresión Génica de las Plantas , Proteínas de Dominio MADS/genética , Proteínas de Dominio MADS/metabolismo , Proteínas de Unión al ARN/metabolismo
19.
J Am Chem Soc ; 146(9): 6178-6188, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38387070

RESUMEN

Random heteropolymers (RHPs) consisting of three or more comonomers have been routinely used to synthesize functional materials. While increasing the monomer variety diversifies the side-chain chemistry, this substantially expands the sequence space and leads to ensemble-level sequence heterogeneity. Most studies have relied on monomer composition and simulated sequences to design RHPs, but the questions remain unanswered regarding heterogeneities within each RHP ensemble and how closely these simulated sequences reflect the experimental outcomes. Here, we quantitatively mapped out the evolution of monomer compositions in four-monomer-based RHPs throughout a design-synthesis-purification-depolymerization process. By adopting a Jaacks method, we first determined 12 reactivity ratios directly from quaternary methacrylate RAFT copolymerization experiments to account for the influences of competitive monomer addition and the reversible activation/deactivation equilibria. The reliability of in silico analysis was affirmed by a quantitative agreement (<4% difference) between the simulated RHP compositions and the experimental results. Furthermore, we mapped out the conformation distribution within each ensemble in different solvents as a function of monomer chemistry, composition, and segmental characteristics via high-throughput computation based on self-consistent field theory (SCFT). These comprehensive studies confirmed monomer composition as a viable design parameter to engineer RHP-based functional materials as long as the reactivity ratios are accurately determined and the livingness of RHP synthesis is ensured.

20.
J Am Chem Soc ; 146(22): 15320-15330, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38683738

RESUMEN

Palladium hydrides (PdHx) are pivotal in both fundamental research and practical applications across a wide spectrum. PdHx nanocrystals, synthesized by heating in dimethylformamide (DMF), exhibit remarkable stability, granting them widespread applications in the field of electrocatalysis. However, this stability appears inconsistent with their metastable nature. The substantial challenges in characterizing nanoscale structures contribute to the limited understanding of this anomalous phenomenon. Here, through a series of well-conceived experimental designs and advanced characterization techniques, including aberration-corrected scanning transmission electron microscopy (AC-STEM), in situ X-ray diffraction (XRD), and time-of-flight secondary ion mass spectrometry (TOF-SIMS), we have uncovered evidence that indicates the presence of C and N within the lattice of Pd (PdCxNy), rather than H (PdHx). By combining theoretical calculations, we have thoroughly studied the potential configurations and thermodynamic stability of PdCxNy, demonstrating a 2.5:1 ratio of C to N infiltration into the Pd lattice. Furthermore, we successfully modulated the electronic structure of Pd nanocrystals through C and N doping, enhancing their catalytic activity in methanol oxidation reactions. This breakthrough provides a new perspective on the structure and composition of Pd-based nanocrystals infused with light elements, paving the way for the development of advanced catalytic materials in the future.

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