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1.
Plant J ; 120(1): 60-75, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39136360

RESUMEN

The intracellular localization of the florigen FLOWERING LOCUS T (FT) is important for its long-distance transport toward the shoot apical meristem. However, the mechanisms regulating the FT localization remain poorly understood. Here, we discovered that in Arabidopsis thaliana, the chloroplast-localized protein THYLAKOID FORMATION 1 (THF1) physically interacts with FT, sequestering FT in the outer chloroplast envelope. Loss of THF1 function led to temperature-insensitive flowering, resulting in early flowering, especially under low ambient temperatures. THF1 mainly acts in the leaf vasculature and shoot apex to prevent flowering. Mutation of CONSTANS or FT completely suppressed the early flowering of thf1-1 mutants. FT and THF1 interact via their anion binding pocket and coiled-coil domain (CCD), respectively. Deletion of the CCD in THF1 by gene editing caused temperature-insensitive early flowering similar to that observed in the thf1-1 mutant. FT levels in the outer chloroplast envelope decreased in the thf1-1 mutant, suggesting that THF1 is important for sequestering FT. Furthermore, THF1 protein levels decreased in seedlings grown at high ambient temperature, suggesting an explanation for its role in plant responses to ambient temperature. A thf1-1 phosphatidylglycerolphosphate synthase 1 (pgp1) double mutant exhibited additive acceleration of flowering at 23 and 16°C, compared to the single mutants, indicating that THF1 and phosphatidylglycerol (PG) act as independent but synergistic regulators of temperature-responsive flowering. Collectively, our results provide an understanding of the genetic pathway involving THF1 and its role in temperature-responsive flowering and reveal a previously unappreciated additive interplay between THF1 and PG in temperature-responsive flowering.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Flores , Regulación de la Expresión Génica de las Plantas , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Flores/genética , Flores/fisiología , Flores/crecimiento & desarrollo , Temperatura , Cloroplastos/metabolismo , Mutación , Plantas Modificadas Genéticamente , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Proteínas de Cloroplastos/genética , Proteínas de Cloroplastos/metabolismo
2.
Nanoscale ; 16(35): 16467-16476, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39157961

RESUMEN

Conventional DRAM, consisting of one transistor and one capacitor (1T1C), requires periodic data refresh processes due to its limited retention time and data-destructive read operation. Here, we propose and demonstrate a novel 3D-DRAM memory scheme available with a single transistor and a single ferroelectric field-effect transistor (FeFET) DRAM (2T0C-FeDRAM), which offers extended retention time and non-destructive read operation. This architecture uses a back-end-of-line (BEOL)-compatible amorphous oxide semiconductor (AOS) that is suitable for increasing DRAM cell density. Notably, the device structures of a double gate a-ITZO/a-IGZO FeFET, used for data storage and reading, are engineered to achieve an enlarged memory window (MW) of 1.5 V and a prolonged retention time of 104 s. This is accomplished by a double gate and an a-ITZO/a-IGZO heterostructure channel to enable efficient polarization control in hafnium-zirconium oxide (HZO) layers. We present successful program/erase operations of the double gate a-ITZO/a-IGZO FeFET through incremental step pulse programming (ISPP), demonstrating multi-level states with remarkable retention characteristics. Most importantly, we perform 2T0C-FeDRAM operations by electrically connecting the double gate a-ITZO/a-IGZO FeFET and the a-ITZO FET. Leveraging the impressive performance of the double gate a-ITZO/a-IGZO FeFET technology, we have effectively showcased an exceptionally record-long retention time exceeding 2000 s and 4-bit multi-level states, positioning it as a robust contender among emerging memory solutions in the era of artificial intelligence.

3.
Heart Vessels ; 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38953938

RESUMEN

Iliac artery angioplasty with stenting is an effective alternative treatment modality for aortoiliac occlusive diseases. Few randomized controlled trials have compared the efficacy and safety between self-expandable stent (SES) and balloon-expandable stent (BES) in atherosclerotic iliac artery disease. In this randomized, multicenter study, patients with common or external iliac artery occlusive disease were randomly assigned in a 1:1 ratio to either BES or SES. The primary end point was the 1-year clinical patency, defined as freedom from any surgical or percutaneous intervention due to restenosis of the target lesion after the index procedure. The secondary end point was a composite event from major adverse clinical events at 1 year. A total of 201 patients were enrolled from 17 major cardiovascular intervention centers in South Korea. The mean age of the enrolled patients was 66.8 ± 8.5 years and 86.2% of the participants were male. The frequency of critical limb ischemia was 15.4%, and the most common target lesion was in the common iliac artery (75.1%). As the primary end point, the 1-year clinical patency as primary end point was 99% in the BES group and 99% in the SES group (p > 0.99). The rate of repeat revascularization at 1 year was 7.8% in the BES group and 7.0% in the SES group (p = 0.985; confidence interval, 1.011 [0.341-2.995]). In our randomized study, the treatment of iliac artery occlusive disease with self-expandable versus balloon-expandable stent was comparable in 12-month clinical outcomes without differences in the procedural success or geographic miss rate regardless of the deployment method in the distal aortoiliac occlusive lesion (ClinicalTrials.gov, NCT01834495).

4.
PLoS Biol ; 22(5): e3002596, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38718086

RESUMEN

Autism spectrum disorders (ASD) frequently accompany macrocephaly, which often involves hydrocephalic enlargement of brain ventricles. Katnal2 is a microtubule-regulatory protein strongly linked to ASD, but it remains unclear whether Katnal2 knockout (KO) in mice leads to microtubule- and ASD-related molecular, synaptic, brain, and behavioral phenotypes. We found that Katnal2-KO mice display ASD-like social communication deficits and age-dependent progressive ventricular enlargements. The latter involves increased length and beating frequency of motile cilia on ependymal cells lining ventricles. Katnal2-KO hippocampal neurons surrounded by enlarged lateral ventricles show progressive synaptic deficits that correlate with ASD-like transcriptomic changes involving synaptic gene down-regulation. Importantly, early postnatal Katnal2 re-expression prevents ciliary, ventricular, and behavioral phenotypes in Katnal2-KO adults, suggesting a causal relationship and a potential treatment. Therefore, Katnal2 negatively regulates ependymal ciliary function and its deletion in mice leads to ependymal ciliary hyperfunction and hydrocephalus accompanying ASD-related behavioral, synaptic, and transcriptomic changes.


Asunto(s)
Trastorno del Espectro Autista , Cilios , Epéndimo , Ratones Noqueados , Fenotipo , Animales , Masculino , Ratones , Trastorno del Espectro Autista/genética , Trastorno del Espectro Autista/metabolismo , Trastorno del Espectro Autista/fisiopatología , Conducta Animal , Cilios/metabolismo , Modelos Animales de Enfermedad , Epéndimo/metabolismo , Hipocampo/metabolismo , Hidrocefalia/genética , Hidrocefalia/metabolismo , Hidrocefalia/patología , Hidrocefalia/fisiopatología , Katanina/metabolismo , Katanina/genética , Ratones Endogámicos C57BL , Neuronas/metabolismo , Sinapsis/metabolismo , Transcriptoma/genética
5.
Methods Mol Biol ; 2795: 227-238, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38594542

RESUMEN

In plants, complex signaling networks monitor and respond to environmental cues to determine the optimal time for the transition from the vegetative to reproductive phase. Understanding these networks requires robust tools to examine the levels and subcellular localization of key factors. The florigen FLOWERING LOCUS T (FT) is a crucial regulator of flowering time and occurs in soluble and membrane-bound forms. At low ambient temperatures, the ratio of these forms of FT undergoes a significant shift, which leads to a delay in the onset of flowering. To investigate these changes in FT localization, epitope-tagged FT protein can be isolated from plants by subcellular fractionation and its localization examined by immunoblot analysis of the resulting fractions. However, the highly abundant protein ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) can interfere with methods to detect and characterize low-abundance proteins such as FT. In this chapter, we present a method for analyzing the ratio of HA-tagged FT (HA:FT) in different subcellular fractions while mitigating the interference from RuBisCO by using protamine sulfate (PS) to deplete RuBisCO during protein purification, thereby enhancing HA:FT detection in fractionated samples.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Florigena/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ribulosa-Bifosfato Carboxilasa/genética , Ribulosa-Bifosfato Carboxilasa/metabolismo , Transducción de Señal , Regulación de la Expresión Génica de las Plantas , Flores/metabolismo
6.
Nature ; 625(7996): 768-777, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38200313

RESUMEN

Cerebrospinal fluid (CSF) in the subarachnoid space around the brain has long been known to drain through the lymphatics to cervical lymph nodes1-17, but the connections and regulation have been challenging to identify. Here, using fluorescent CSF tracers in Prox1-GFP lymphatic reporter mice18, we found that the nasopharyngeal lymphatic plexus is a major hub for CSF outflow to deep cervical lymph nodes. This plexus had unusual valves and short lymphangions but no smooth-muscle coverage, whereas downstream deep cervical lymphatics had typical semilunar valves, long lymphangions and smooth muscle coverage that transported CSF to the deep cervical lymph nodes. α-Adrenergic and nitric oxide signalling in the smooth muscle cells regulated CSF drainage through the transport properties of deep cervical lymphatics. During ageing, the nasopharyngeal lymphatic plexus atrophied, but deep cervical lymphatics were not similarly altered, and CSF outflow could still be increased by adrenergic or nitric oxide signalling. Single-cell analysis of gene expression in lymphatic endothelial cells of the nasopharyngeal plexus of aged mice revealed increased type I interferon signalling and other inflammatory cytokines. The importance of evidence for the nasopharyngeal lymphatic plexus functioning as a CSF outflow hub is highlighted by its regression during ageing. Yet, the ageing-resistant pharmacological activation of deep cervical lymphatic transport towards lymph nodes can still increase CSF outflow, offering an approach for augmenting CSF clearance in age-related neurological conditions in which greater efflux would be beneficial.


Asunto(s)
Líquido Cefalorraquídeo , Vértebras Cervicales , Drenaje , Vasos Linfáticos , Animales , Ratones , Envejecimiento/metabolismo , Líquido Cefalorraquídeo/metabolismo , Vértebras Cervicales/metabolismo , Células Endoteliales/metabolismo , Fluorescencia , Genes Reporteros , Interferón Tipo I/inmunología , Interferón Tipo I/metabolismo , Vasos Linfáticos/fisiología , Miocitos del Músculo Liso/metabolismo , Óxido Nítrico/metabolismo , Nariz/fisiología , Faringe/metabolismo , Receptores Adrenérgicos alfa/metabolismo , Análisis de la Célula Individual , Transducción de Señal
7.
Plant Commun ; 5(4): 100814, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38213026

RESUMEN

Ambient temperature affects flowering time in plants, and the MADS-box transcription factor SHORT VEGETATIVE PHASE (SVP) plays a crucial role in the response to changes in ambient temperature. SVP protein stability is regulated by the 26S proteasome pathway and decreases at high ambient temperature, but the details of SVP degradation are unclear. Here, we show that SVP degradation at high ambient temperature is mediated by the CULLIN3-RING E3 ubiquitin ligase (CRL3) complex in Arabidopsis thaliana. We identified a previously uncharacterized protein that interacts with SVP at high ambient temperature and contains a BTB/POZ domain. We named this protein LATE FLOWERING AT HIGH TEMPERATURE 1 (LFH1). Single mutants of LFH1 or CULLIN3A (CUL3A) showed late flowering specifically at 27°C. LFH1 protein levels increased at high ambient temperature. We found that LFH1 interacts with CUL3A in the cytoplasm and is important for SVP-CUL3A complex formation. Mutations in CUL3A and/or LFH1 led to increased SVP protein stability at high ambient temperature, suggesting that the CUL3-LFH1 complex functions in SVP degradation. Screening E2 ubiquitin-conjugating enzymes (UBCs) using RING-BOX PROTEIN 1 (RBX1), a component of the CRL3 complex, as bait identified UBC15. ubc15 mutants also showed late flowering at high ambient temperature. In vitro and in vivo ubiquitination assays using recombinant CUL3A, LFH1, RBX1, and UBC15 showed that SVP is highly ubiquitinated in an ATP-dependent manner. Collectively, these results indicate that the degradation of SVP at high ambient temperature is mediated by a CRL3 complex comprising CUL3A, LFH1, and UBC15.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Ubiquitina-Proteína Ligasas , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Ligasas/metabolismo , Temperatura , Ubiquitinas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo
8.
Sci Immunol ; 8(88): eadg6155, 2023 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-37801517

RESUMEN

High neonatal susceptibility to meningitis has been attributed to the anatomical barriers that act to protect the central nervous system (CNS) from infection being immature and not fully developed. However, the mechanisms by which pathogens breach CNS barriers are poorly understood. Using the Armstrong strain of lymphocytic choriomeningitis virus (LCMV) to study virus propagation into the CNS during systemic infection, we demonstrate that mortality in neonatal, but not adult, mice is high after infection. Virus propagated extensively from the perivenous sinus region of the dura mater to the leptomeninges, choroid plexus, and cerebral cortex. Although the structural barrier of CNS border tissues is comparable between neonates and adults, immunofluorescence staining and single-cell RNA sequencing analyses revealed that the neonatal dural immune cells are immature and predominantly composed of CD206hi macrophages, with major histocompatibility complex class II (MHCII)hi macrophages being rare. In adults, however, perivenous sinus immune cells were enriched in MHCIIhi macrophages that are specialized for producing antiviral molecules and chemokines compared with CD206hi macrophages and protected the CNS against systemic virus invasion. Our findings clarify how systemic pathogens enter the CNS through its border tissues and how the immune barrier at the perivenous sinus region of the dura blocks pathogen access to the CNS.


Asunto(s)
Encefalitis Viral , Coriomeningitis Linfocítica , Meningitis Viral , Meningoencefalitis , Ratones , Animales , Sistema Nervioso Central , Meninges , Virus de la Coriomeningitis Linfocítica
9.
Nanomaterials (Basel) ; 13(19)2023 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-37836345

RESUMEN

The continuous advancement of Artificial Intelligence (AI) technology depends on the efficient processing of unstructured data, encompassing text, speech, and video. Traditional serial computing systems based on the von Neumann architecture, employed in information and communication technology development for decades, are not suitable for the concurrent processing of massive unstructured data tasks with relatively low-level operations. As a result, there arises a pressing need to develop novel parallel computing systems. Recently, there has been a burgeoning interest among developers in emulating the intricate operations of the human brain, which efficiently processes vast datasets with remarkable energy efficiency. This has led to the proposal of neuromorphic computing systems. Of these, Spiking Neural Networks (SNNs), designed to closely resemble the information processing mechanisms of biological neural networks, are subjects of intense research activity. Nevertheless, a comprehensive investigation into the relationship between spike shapes and Spike-Timing-Dependent Plasticity (STDP) to ensure efficient synaptic behavior remains insufficiently explored. In this study, we systematically explore various input spike types to optimize the resistive memory characteristics of Hafnium-based Ferroelectric Tunnel Junction (FTJ) devices. Among the various spike shapes investigated, the square-triangle (RT) spike exhibited good linearity and symmetry, and a wide range of weight values could be realized depending on the offset of the RT spike. These results indicate that the spike shape serves as a crucial indicator in the alteration of synaptic connections, representing the strength of the signals.

10.
Nanomaterials (Basel) ; 13(15)2023 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-37570505

RESUMEN

Hf1-xZrxO2 (HZO) thin films are versatile materials suitable for advanced ferroelectric semiconductor devices. Previous studies have shown that the ferroelectricity of HZO thin films can be stabilized by doping them with group III elements at low concentrations. While doping with Y improves the ferroelectric properties, there has been limited research on Y-HZO thin films fabricated using atomic layer deposition (ALD). In this study, we investigated the effects of Y-doping cycles on the ferroelectric and electrical properties of as-deposited Y-HZO thin films with varying compositions fabricated through ALD. The Y-HZO thin films were stably crystallized without the need for post-thermal treatment and exhibited transition behavior depending on the Y-doping cycle and initial composition ratio of the HZO thin films. These Y-HZO thin films offer several advantages, including enhanced dielectric constant, leakage current density, and improved endurance. Moreover, the optimized Y-doping cycle induced a phase transformation that resulted in Y-HZO thin films with improved ferroelectric properties, exhibiting stable behavior without fatigue for up to 1010 cycles. These as-deposited Y-HZO thin films show promise for applications in semiconductor devices that require high ferroelectric properties, excellent electrical properties, and reliable performance with a low thermal budget.

11.
Plant Commun ; 4(3): 100515, 2023 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-36597356

RESUMEN

The timing of flowering is tightly controlled by signals that integrate environmental and endogenous cues. Sugars produced by carbon fixation in the chloroplast are a crucial endogenous cue for floral initiation. Chloroplasts also convey information directly to the nucleus through retrograde signaling to control plant growth and development. Here, we show that mutants defective in chlorophyll biosynthesis and chloroplast development flowered early, especially under long-day conditions, although low sugar accumulation was seen in some mutants. Plants treated with the bleaching herbicide norflurazon also flowered early, suggesting that chloroplasts have a role in floral repression. Among retrograde signaling mutants, the golden2-like 1 (glk1) glk2 double mutants showed early flowering under long-day conditions. This early flowering was completely suppressed by constans (co) and flowering locus t (ft) mutations. Leaf vascular-specific knockdown of both GLK1 and GLK2 phenocopied the glk1 glk2 mutants. GLK1 and GLK2 repress flowering by directly activating the expression of B-BOX DOMAIN PROTEIN 14 (BBX14), BBX15, and BBX16 via CCAATC cis-elements in the BBX genes. BBX14/15/16 physically interact with CO in the nucleus, and expression of BBXs hampered CO-mediated FT transcription. Simultaneous knockdown of BBX14/15/16 by artificial miRNA (35S::amiR-BBX14/15/16) caused early flowering with increased FT transcript levels, whereas BBX overexpression caused late flowering. Flowering of glk1/2 and 35S::amiR-BBX14/15/16 plants was insensitive to norflurazon treatment. Taking these observations together, we propose that the GLK1/2-BBX14/15/16 module provides a novel mechanism explaining how the chloroplast represses flowering to balance plant growth and reproductive development.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Unión al ADN/genética , Cloroplastos/metabolismo
12.
Nat Cardiovasc Res ; 2(5): 449-466, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-39196043

RESUMEN

Understanding the function of the nasal vasculature in homeostasis and pathogenesis of common nasal diseases is important. Here we describe an extensive network of venous sinusoids (VSs) in mouse and human nasal mucosa. The endothelium of the VSs expressed Prox1 (considered to be a constitutive marker of lymphatic endothelium) and high levels of VCAM-1 and exhibited unusual cell-to-cell junctions. VSs are supported by circular smooth muscle cells (SMCs) and surrounded by immune cells. The nasal mucosa also showed a rich supply of lymphatic vessels with distinctive features, such as the absence of the lymphatic marker LYVE1 and sharp-ended capillaries. In mouse models of allergic rhinitis or acute Coronavirus Disease 2019 (COVID-19) infection, Prox1+ VSs were regressed or compromised. However, in aged mice, the VSs lost the SMC support and were expanded and enlarged. Our findings demonstrate three-dimensional morphological and molecular heterogeneities of the nasal vasculature and offer insights into their associations with nasal inflammation, infection and aging.


Asunto(s)
COVID-19 , Mucosa Nasal , Animales , Humanos , COVID-19/patología , COVID-19/inmunología , Mucosa Nasal/patología , Mucosa Nasal/metabolismo , Ratones , Rinitis Alérgica/patología , Imagenología Tridimensional , SARS-CoV-2 , Vasos Linfáticos/patología , Vasos Linfáticos/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas Supresoras de Tumor/genética , Masculino , Proteínas de Homeodominio/metabolismo , Proteínas de Homeodominio/genética , Ratones Endogámicos C57BL , Modelos Animales de Enfermedad , Femenino , Miocitos del Músculo Liso/patología , Miocitos del Músculo Liso/metabolismo
13.
Front Plant Sci ; 14: 1346245, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38264023

RESUMEN

[This corrects the article DOI: 10.3389/fpls.2022.817356.].

14.
Mol Plant ; 15(11): 1696-1709, 2022 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-36016495

RESUMEN

Temperature is an important environmental cue that affects flowering time in plants. The MADS-box transcription factor FLOWERING LOCUS M (FLM) forms a heterodimeric complex with SHORT VEGETATIVE PHASE (SVP) and controls ambient temperature-responsive flowering in Arabidopsis. FLM-ß and FLM-δ, two major splice variants produced from the FLM locus, exert opposite effects on flowering, but the molecular mechanism by which the interaction between FLM isoforms and SVP affects temperature-responsive flowering remains poorly understood. Here, we show that FLM-ß and FLM-δ play important roles in modulating the temperature-dependent behavior, conformation, and stability of SVP. Nuclear localization of SVP decreases as temperature increases. FLM-ß is required for SVP nuclear translocation at low temperature, whereas SVP interacts with FLM-δ mainly in the cytoplasm at high temperature. SVP preferentially binds to FLM-ß at low temperature in tobacco leaf cells. SVP shows high binding affinity to FLM-ß at low temperature and to FLM-δ at high temperature. SVP undergoes similar structural changes in the interactions with FLM-ß and FLM-δ; however, FLM-δ likely causes more pronounced conformational changes in the SVP structure. FLM-δ causes rapid degradation of SVP at high temperature, compared with FLM-ß, possibly via ubiquitination. Mutation of lysine 53 or lysine 165 in SVP causes increased abundance of SVP due to reduced ubiquitination of SVP and thus delays flowering at high temperature. Our findings suggest that temperature-dependent differential interactions between SVP and FLM isoforms modulate the temperature-responsive induction of flowering in Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Dominio MADS/genética , Proteínas de Dominio MADS/metabolismo , Temperatura , Flores/metabolismo , Lisina/metabolismo , Regulación de la Expresión Génica de las Plantas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
15.
Bio Protoc ; 12(10): e4421, 2022 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-35813025

RESUMEN

Protein-lipid interactions play important roles in many biological processes, including metabolism, signaling, and transport; however, computational and structural analyses often fail to predict such interactions, and determining which lipids participate in these interactions remains challenging. In vitro assays to assess the physical interaction between a protein of interest and a panel of phospholipids provide crucial information for predicting the functionality of these interactions in vivo. In this protocol, which we developed in the context of evaluating protein-lipid binding of the Arabidopsis thaliana florigen FLOWERING LOCUS T, we describe four independent in vitro experiments to determine the interaction of a protein with phospholipids: lipid-protein overlay assays, liposome binding assays, biotin-phospholipid pull-down assays, and fluorescence polarization assays. These complementary assays allow the researcher to test whether the protein of interest interacts with lipids in the test panel, identify the relevant lipids, and assess the strength of the interaction.

16.
Nano Lett ; 22(11): 4589-4595, 2022 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-35536043

RESUMEN

The ultrathin and continuous ruthenium (Ru) film was deposited through an improved atomic layer deposition (ALD) process with a discrete feeding method (DFM), called DF-ALD, employing a cut-in purge step during the precursor feeding. The excess precursor molecules can be physically adsorbed onto the chemisorbed precursors on the substrate during precursor feeding, which screens the reactive sites on the surface. Using DF-ALD, surface coverage of precursors was enhanced because the cut-in purge removes the physisorbed precursors securing the reactive sites beneath them; thus, nucleation density was greatly increased. Therefore, the grain size decreased, which changed the microstructure and increased oxygen impurity concentration. However, a more metallic Ru thin film was formed due to thermodynamic stability and improved physical density. Consequently, DF-ALD enables the deposition of the ultrathin (3 nm) and continuous Ru film with a low resistivity of ∼60 µΩ cm and a high effective work function of ∼4.8 eV.

17.
Front Plant Sci ; 13: 817356, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35222476

RESUMEN

RNA polymerase II-associated factor 1 complex (PAF1C) regulates the transition from the vegetative to the reproductive phase primarily by modulating the expression of FLOWERING LOCUS C (FLC) and FLOWERING LOCUS M [FLM, also known as MADS AFFECTING FLOWERING1 (MAF1)] at standard growth temperatures. However, the role of PAF1C in the regulation of flowering time at chilling temperatures (i.e., cold temperatures that are above freezing) and whether PAF1C affects other FLC-clade genes (MAF2-MAF5) remains unknown. Here, we showed that Arabidopsis thaliana mutants of any of the six known genes that encode components of PAF1C [CELL DIVISION CYCLE73/PLANT HOMOLOGOUS TO PARAFIBROMIN, VERNALIZATION INDEPENDENCE2 (VIP2)/EARLY FLOWERING7 (ELF7), VIP3, VIP4, VIP5, and VIP6/ELF8] showed temperature-insensitive early flowering across a broad temperature range (10°C-27°C). Flowering of PAF1C-deficient mutants at 10°C was even earlier than that in flc, flm, and flc flm mutants, suggesting that PAF1C regulates additional factors. Indeed, RNA sequencing (RNA-Seq) of PAF1C-deficient mutants revealed downregulation of MAF2-MAF5 in addition to FLC and FLM at both 10 and 23°C. Consistent with the reduced expression of FLC and the FLC-clade members FLM/MAF1 and MAF2-MAF5, chromatin immunoprecipitation (ChIP)-quantitative PCR assays showed reduced levels of the permissive epigenetic modification H3K4me3/H3K36me3 and increased levels of the repressive modification H3K27me3 at their chromatin. Knocking down MAF2-MAF5 using artificial microRNAs (amiRNAs) in the flc flm background (35S::amiR-MAF2-5 flc flm) resulted in significantly earlier flowering than flc flm mutants and even earlier than short vegetative phase (svp) mutants at 10°C. Wild-type seedlings showed higher accumulation of FLC and FLC-clade gene transcripts at 10°C compared to 23°C. Our yeast two-hybrid assays and in vivo co-immunoprecipitation (Co-IP) analyses revealed that MAF2-MAF5 directly interact with the prominent floral repressor SVP. Late flowering caused by SVP overexpression was almost completely suppressed by the elf7 and vip4 mutations, suggesting that SVP-mediated floral repression required a functional PAF1C. Taken together, our results showed that PAF1C regulates the transcription of FLC and FLC-clade genes to modulate temperature-responsive flowering at a broad range of temperatures and that the interaction between SVP and these FLC-clade proteins is important for floral repression.

18.
Plant Cell Environ ; 45(2): 479-495, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34778961

RESUMEN

Dolichols (Dols), ubiquitous components of living organisms, are indispensable for cell survival. In plants, as well as other eukaryotes, Dols are crucial for post-translational protein glycosylation, aberration of which leads to fatal metabolic disorders in humans and male sterility in plants. Until now, the mechanisms underlying Dol accumulation remain elusive. In this study, we have analysed the natural variation of the accumulation of Dols and six other isoprenoids among more than 120 Arabidopsis thaliana accessions. Subsequently, by combining QTL and GWAS approaches, we have identified several candidate genes involved in the accumulation of Dols, polyprenols, plastoquinone and phytosterols. The role of two genes implicated in the accumulation of major Dols in Arabidopsis-the AT2G17570 gene encoding a long searched for cis-prenyltransferase (CPT3) and the AT1G52460 gene encoding an α/ß-hydrolase-is experimentally confirmed. These data will help to generate Dol-enriched plants which might serve as a remedy for Dol-deficiency in humans.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Dolicoles/metabolismo , Hidrolasas/genética , Transferasas/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Dolicoles/genética , Hidrolasas/metabolismo , Transferasas/metabolismo
19.
Science ; 373(6559): 1137-1142, 2021 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-34516842

RESUMEN

Plants respond to temperature changes by modulating florigen activity to optimize the timing of flowering. We show that the Arabidopsis thaliana mobile florigen FLOWERING LOCUS T (FT) interacts with the negatively charged phospholipid phosphatidylglycerol (PG) at cellular membranes and binds the lipid bilayer. Perturbing PG biosynthesis in phloem companion cells leads to temperature-insensitive early flowering. Low temperatures facilitate FT sequestration in the cellular membrane of the companion cell, thus reducing soluble FT levels and delaying flowering. A mutant in PHOSPHATIDYLGLYCEROLPHOSPHATE SYNTHASE 1 accumulates more soluble FT at lower temperatures and exhibits reduced temperature sensitivity. Thus, cellular membranes sequester FT through their ability to bind the phospholipid PG, and this sequestration modulates the plant's response to temperature changes.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Membrana Celular/metabolismo , Florigena/metabolismo , Flores/metabolismo , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Transporte Activo de Núcleo Celular , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Fosfatidilgliceroles/metabolismo , Plantas Modificadas Genéticamente , Temperatura
20.
J Exp Bot ; 72(20): 7049-7066, 2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34270724

RESUMEN

The nonsense-mediated mRNA decay (NMD) surveillance system clears aberrant mRNAs from the cell, thus preventing the accumulation of truncated proteins. Although loss of the core NMD proteins UP-FRAMESHIFT1 (UPF1) and UPF3 leads to late flowering in Arabidopsis, the underlying mechanism remains elusive. Here, we showed that mutations in UPF1 and UPF3 cause temperature- and photoperiod-independent late flowering. Expression analyses revealed high FLOWERING LOCUS C (FLC) mRNA levels in upf mutants; in agreement with this, the flc mutation strongly suppressed the late flowering of upf mutants. Vernalization accelerated flowering of upf mutants in a temperature-independent manner. FLC transcript levels rose in wild-type plants upon NMD inhibition. In upf mutants, we observed increased enrichment of H3K4me3 and reduced enrichment of H3K27me3 in FLC chromatin. Transcriptome analyses showed that SET DOMAIN GROUP 40 (SDG40) mRNA levels increased in upf mutants, and the SDG40 transcript underwent NMD-coupled alternative splicing, suggesting that SDG40 affects flowering time in upf mutants. Furthermore, NMD directly regulated SDG40 transcript stability. The sdg40 mutants showed decreased H3K4me3 and increased H3K27me3 levels in FLC chromatin, flowered early, and rescued the late flowering of upf mutants. Taken together, these results suggest that NMD epigenetically regulates FLC through SDG40 to modulate flowering time in Arabidopsis.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas , Degradación de ARNm Mediada por Codón sin Sentido , Dominios PR-SET , ARN Helicasas/genética
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