ABSTRACT
We present a 320 × 240 CMOS image sensor (CIS) using the proposed hybrid-correlated multiple sampling (HMS) technique with an adaptive dual-gain analog-to-digital converter (ADC). The proposed HMS improves the noise characteristics under low illumination by adjusting the ADC gain according to the incident light on the pixels. Depending on whether it is less than or greater than 1/4 of the full output voltage range from pixels, either correlated multiple sampling or conventional-correlated double sampling (CDS) is used with different slopes of the ramping signals. The proposed CIS achieves 11-bit resolution of the ADC using an up-down counter that controls the LSB depending on the ramping signals used. The sensor was fabricated using a 0.11 µm CIS process, and the total chip area was 2.55 mm × 4.3 mm. Compared to the conventional CDS, the measurement results showed that the maximum dark random noise was reduced by 26.7% with the proposed HMS, and the maximum figure of merit was improved by 49.1%. The total power consumption was 5.1 mW at 19 frames per second with analog, pixel, and digital supply voltages of 3.3 V, 3.3 V, and 1.5 V, respectively.
ABSTRACT
KEY MESSAGE: TCX8 localizes to nucleus and has transcriptional repression activity. TCX8 binds to the promoter region of LOX2 encoding lipoxygenase, causing JA biosynthesis suppression, and thereby delays plant senescence. Conserved CXC domain-containing proteins are found in most eukaryotes. Eight TCX proteins, which are homologs of animal CXC-Hinge-CXC (CHC) proteins, were identified in Arabidopsis, and three of them, TSO1, TCX2/SOL2 and TCX3/SOL1, have been reported to affect cell-cycle control. TCX8, one of the TCX family proteins, was believed to be a TF but its precise function has not been reported. Yeast two-hybrid screening revealed TCP20, a TF that binds to the promoter of LOX2 encoding lipoxygenase, as a strong candidate for interaction with TCX8. We confirmed that TCX8 directly interacts with TCP20 using in vitro pull-down assay and in vivo BiFC and observed that TCX8, as a TF, localizes to nucleus. Using EMSA and by analyzing phenotypes of TCX8-overexpression lines, we demonstrated that TCX8 regulates the expression of LOX2 by binding to either cis-element of LOX2 promoter to which TCP20 or TCP4 binds, affecting JA biosynthesis, and thereby delaying plant senescence. Our study provides new information about the role of TCX8 in modulating plant senescence through regulating LOX2 expression.
Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/genetics , Lipoxygenases/genetics , Arabidopsis/physiology , Arabidopsis Proteins/metabolism , Binding Sites , Cell Nucleus/genetics , Cell Nucleus/metabolism , Gene Expression Regulation, Plant , Lipoxygenases/metabolism , Plants, Genetically Modified , Promoter Regions, Genetic , Protein Interaction Maps , Transcription Factors/genetics , Transcription Factors/metabolism , Two-Hybrid System TechniquesABSTRACT
This paper presents a CMOS image sensor (CIS) with built-in lane detection computing circuits for automotive applications. We propose on-CIS processing with an edge detection mask used in the readout circuit of the conventional CIS structure for high-speed lane detection. Furthermore, the edge detection mask can detect the edges of slanting lanes to improve accuracy. A prototype of the proposed CIS was fabricated using a 110 nm CIS process. It has an image resolution of 160 (H) × 120 (V) and a frame rate of 113, and it occupies an area of 5900 µm × 5240 µm. A comparison of its lane detection accuracy with that of existing edge detection algorithms shows that it achieves an acceptable accuracy. Moreover, the total power consumption of the proposed CIS is 9.7 mW at pixel, analog, and digital supply voltages of 3.3, 3.3, and 1.5 V, respectively.
ABSTRACT
KEY MESSAGE: The chloroplast-localized protein CSAP is an ABA-responsive factor and positively regulates dark-induced senescence. This phenomenon is controlled by SAUL1 in Arabidopsis. We report here that CSAP (Chloroplast-localized Senescence-Associated Protein, AT5G39520) functions as a positive regulator of senescence and is controlled by SAUL1 (Senescence Associated E3 Ubiquitin Ligase 1) in Arabidopsis. CSAP transcript level was gradually increased when senescence was progressed. Under dark conditions, the csap mutant showed delayed leaf senescence and reduced chlorophyll breakdown, but overexpression of CSAP accelerated leaf senescence and expressions of chlorophyll catabolic genes were up-regulated compared to the wild-type (WT). NCED3 and AAO3, which are involved in ABA biosynthesis, also showed higher expression in the overexpression lines than the WT. It is known that the CSAP transcript is increased in the saul1 mutant that shows precocious senescence. In our experiments, we confirmed that CSAP interacts with SAUL1 by the yeast two-hybrid and pull-down assays. In addition, we found that SAUL1 decreases the stability of CSAP in the presence of ABA. Taken together, we suggest that CSAP accelerates leaf senescence in the dark and this process is controlled by SAUL1.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Chloroplast Proteins/metabolism , Darkness , Membrane Proteins/metabolism , Plant Leaves/growth & development , Ubiquitin-Protein Ligases/metabolism , Abscisic Acid/pharmacology , Arabidopsis/drug effects , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Chloroplast Proteins/genetics , Chloroplasts/drug effects , Chloroplasts/metabolism , Gene Expression Regulation, Plant/drug effects , Membrane Proteins/genetics , Mutation/genetics , Phenotype , Plant Leaves/drug effects , Plants, Genetically Modified , Protein Binding/drug effects , Protein Stability/drug effectsABSTRACT
In this paper, we propose a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) that has built-in mask circuits to selectively capture either edge-detection images or normal 8-bit images for low-power computer vision applications. To detect the edges of images in the CIS, neighboring column data are compared in in-column memories after column-parallel analog-to-digital conversion with the proposed mask. The proposed built-in mask circuits are implemented in the CIS without a complex image signal processer to obtain edge images with high speed and low power consumption. According to the measurement results, edge images were successfully obtained with a maximum frame rate of 60 fps. A prototype sensor with 1920 × 1440 resolution was fabricated with a 90-nm 1-poly 5-metal CIS process. The area of the 4-shared 4T-active pixel sensor was 1.4 × 1.4 µm2, and the chip size was 5.15 × 5.15 mm2. The total power consumption was 9.4 mW at 60 fps with supply voltages of 3.3 V (analog), 2.8 V (pixel), and 1.2 V (digital).
ABSTRACT
This paper presents an always-on Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) using an analog convolutional neural network for image classification in mobile applications. To reduce the power consumption as well as the overall processing time, we propose analog convolution circuits for computing convolution, max-pooling, and correlated double sampling operations without operational transconductance amplifiers. In addition, we used the voltage-mode MAX circuit for max pooling in the analog domain. After the analog convolution processing, the image data were reduced by 99.58% and were converted to digital with a 4-bit single-slope analog-to-digital converter. After the conversion, images were classified by the fully connected processor, which is traditionally performed in the digital domain. The measurement results show that we achieved an 89.33% image classification accuracy. The prototype CIS was fabricated in a 0.11 µm 1-poly 4-metal CIS process with a standard 4T-active pixel sensor. The image resolution was 160 × 120, and the total power consumption of the proposed CIS was 1.12 mW with a 3.3 V supply voltage and a maximum frame rate of 120.
ABSTRACT
HJURP is a key factor for CENP-A deposition and maintenance in centromeres. The role of mis-regulation of histone chaperones in cancer initiation and progression has been studied. However, its role in colorectal cancer is still unclear. In this study, we aimed to evaluate the expression of HJURP in 162 colorectal cancer tissue. To investigate the function of HJURP in the colorectal cancer cell, we suppressed HJURP expression by siRNA and confirmed proliferation, migration, invasion, and anchorage independent of colony forming ability. The association between HJURP expression levels and clinicopathological factors was evaluated in 162 CRC tissues using immunohistochemistry. The overall survival rate in patients of HJURP high expression was higher than those in HJURP low expression in CRC. Suppressing HJURP expression decreased cellular proliferation, invasion, and migration in four CRC cell lines: HT29, HCT116, SW480, SW620 in vitro study. Our findings revealed that the knockdown of HJURP suppressed the proliferation, migration, invasion, and tumorigenicity in CRC cells. Due to its strong association with CRC, HJURP could be a potential prognostic biomarker and a novel target for drug discovery.
Subject(s)
Biomarkers, Tumor/metabolism , Colorectal Neoplasms/surgery , DNA-Binding Proteins/metabolism , Up-Regulation , Cell Line, Tumor , Cell Movement , Cell Proliferation , Colorectal Neoplasms/metabolism , Female , Gene Expression Regulation, Neoplastic , HCT116 Cells , HT29 Cells , Humans , Male , Prognosis , Survival Analysis , Treatment OutcomeABSTRACT
The phytohormone abscisic acid (ABA) plays crucial roles in various physiological processes, including responses to abiotic stresses, in plants. Recently, multiple ABA transporters were identified. The loss-of-function and gain-of-function mutants of these transporters show altered ABA sensitivity and stomata regulation, highlighting the importance of ABA transporters in ABA-mediated processes. However, how the activity of these transporters is regulated remains elusive. Here, we show that spatial regulation of ATP BINDING CASETTE G25 (ABCG25), an ABA exporter, is an important mechanism controlling its activity. ABCG25, as a soluble green fluorescent protein (sGFP) fusion, was subject to posttranslational regulation via clathrin-dependent and adaptor protein complex-2-dependent endocytosis followed by trafficking to the vacuole. The levels of sGFP:ABCG25 at the plasma membrane (PM) were regulated by abiotic stresses and exogenously applied ABA; PM-localized sGFP:ABCG25 decreased under abiotic stress conditions via activation of endocytosis in an ABA-independent manner, but increased upon application of exogenous ABA via activation of recycling from early endosomes in an ABA-dependent manner. Based on these findings, we propose that the spatial regulation of ABCG25 is an important component of the mechanism by which plants fine-tune cellular ABA levels according to cellular and environmental conditions.
Subject(s)
ATP-Binding Cassette Transporters/metabolism , Abscisic Acid/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , ATP-Binding Cassette Transporters/genetics , Abscisic Acid/genetics , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Cell Membrane/metabolism , Gene Expression Regulation, Plant , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolismABSTRACT
KEY MESSAGE: The trichome-related protein (TRP) is a novel transcription factor (TF) that negatively regulates trichome initiation-related TFs through gibberellin (GA) signaling. Trichomes, which are outgrowths of leaf epidermal cells, provide the plant with a first line of defense against damage from herbivores and reduce transpiration. The initiation and development of trichomes are regulated by a network of positively or negatively regulating transcription factors (TFs). However, little information is currently available on transcriptional regulation related to trichome formation. Here, we report a novel TF Trichome-Related Protein (TRP) that was observed to negatively regulate the trichome initiation-related TFs through gibberellic acid (GA) signaling. ProTRP:GUS revealed that TRP was only expressed in the trichome. The TRP loss-of-function mutant (trp) had an increased number of trichomes on the flower, cauline leaves, and main inflorescence stems compared to the wild-type. In contrast, TRP overexpression lines (TRP-Ox) exhibited a decreased number of trichomes on cauline leaves and main inflorescence stem following treatment with exogenous GA. Moreover, the expressions of trichome initiation regulators (GIS, GIS2, ZFP8, GL1, and GL3) increased in trp plants but decreased in TRP-Ox lines after GA treatment. TRP was observed to physically interact with ZFP5, a C2H2 TF that controls trichome cell development through GA signaling, both in vivo and in vitro. Based on these results, we suggest that TRP functions upstream of the trichome initiation regulators and represses the binding of ZFP5 to the ZFP8 promoter.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Gibberellins/pharmacology , Transient Receptor Potential Channels/metabolism , Trichomes/metabolism , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant/drug effects , Mutation , Plant Growth Regulators/pharmacology , Signal Transduction/drug effects , Transcription Factors/genetics , Transcription Factors/metabolism , Transient Receptor Potential Channels/geneticsABSTRACT
This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm² with a 0.18 µm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency.
Subject(s)
Algorithms , Humans , IrisABSTRACT
In this paper, we present a multi-resolution mode CMOS image sensor (CIS) for intelligent surveillance system (ISS) applications. A low column fixed-pattern noise (CFPN) comparator is proposed in 8-bit two-step single-slope analog-to-digital converter (TSSS ADC) for the CIS that supports normal, 1/2, 1/4, 1/8, 1/16, 1/32, and 1/64 mode of pixel resolution. We show that the scaled-resolution images enable CIS to reduce total power consumption while images hold steady without events. A prototype sensor of 176 × 144 pixels has been fabricated with a 0.18 µm 1-poly 4-metal CMOS process. The area of 4-shared 4T-active pixel sensor (APS) is 4.4 µm × 4.4 µm and the total chip size is 2.35 mm × 2.35 mm. The maximum power consumption is 10 mW (with full resolution) with supply voltages of 3.3 V (analog) and 1.8 V (digital) and 14 frame/s of frame rates.
ABSTRACT
Phospholipase A2(PLA2) hydrolyzes phospholipid molecules to produce two products that are both precursors of second messengers of signaling pathways and signaling molecules per se.Arabidopsis thaliana PLA2 paralogs (-ß,-γ and -δ) play critical roles during pollen development, pollen germination and tube growth. In this study, analysis of the PLA2-γ promoter using a deletion series revealed that the promoter region -153 to -1 is crucial for its pollen specificity. Using a yeast one-hybrid screening assay with the PLA2-γ promoter and an Arabidopsis transcription factor (TF)-only library, we isolated two novel MYB-like TFs belonging to the MYB-CC family, denoted here as γMYB1 and γMYB2. By electrophoretic mobility shift assay, we found that these two TFs bind directly to the P1BS (phosphate starvation response 1-binding sequence)cis-element of the PLA2-γ promoter. γMYB1 alone functioned as a transcriptional activator for PLA2-γ expression, whereas γMYB2 directly interacted with γMYB1 and enhanced its activation. Overexpression of γMYB1 in the mature pollen grain led to increased expression of not only the PLA2-γ gene but also of several genes whose promoters contain the P1BS cis-element and which are involved in the Pi starvation response, phospholipid biosynthesis and sugar synthesis. Based on these results, we suggest that the TF γMYB1 binds to the P1BS cis-element, activates the expression of PLA2-γ with the assistance of its co-activator, γMYB2, and regulates the expression of several target genes involved in many plant metabolic reactions.
Subject(s)
Arabidopsis Proteins/metabolism , Group IB Phospholipases A2/metabolism , Trans-Activators/metabolism , Transcription Factors/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Binding Sites , Cell Nucleus/metabolism , Gene Expression Regulation, Plant , Group IB Phospholipases A2/genetics , Plants, Genetically Modified , Pollen/genetics , Promoter Regions, Genetic , Response Elements , Trans-Activators/genetics , Transcription Factors/geneticsABSTRACT
Calmodulins (CaMs) regulate numerous Ca(2+) -mediated cellular processes in plants by interacting with their respective downstream effectors. Due to the limited number of CaMs, other calcium sensors modulate the regulation of Ca(2+) -mediated cellular processes that are not managed by CaMs. Of 50 CaM-like (CML) proteins identified in Arabidopsis thaliana, we characterized the function of CML10. Yeast two-hybrid screening revealed phosphomannomutase (PMM) as a putative interaction partner of CML10. In vitro and in vivo interaction assays were performed to analyze the interaction mechanisms of CML10 and PMM. PMM activity and the phenotypes of cml10 knock-down mutants were studied to elucidate the role(s) of the CML10-PMM interaction. PMM interacted specifically with CML10 in the presence of Ca(2+) through its multiple interaction motifs. This interaction promoted the activity of PMM. The phenotypes of cml10 knock-down mutants were more sensitive to stress conditions than wild-type plants, corresponding with the fact that PMM is an enzyme which modulates the biosynthesis of ascorbic acid, an antioxidant. The results of this research demonstrate that a calcium sensor, CML10, which is an evolutionary variant of CaM, modulates the stress responses in Arabidopsis by regulating ascorbic acid production.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/physiology , Ascorbic Acid/biosynthesis , Calmodulin/metabolism , Phosphotransferases (Phosphomutases)/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Ascorbic Acid/metabolism , Calcium/metabolism , Calmodulin/genetics , Gene Expression Regulation, Plant , Mutation , Oxidative Stress/physiology , Phosphotransferases (Phosphomutases)/genetics , Protein Interaction Domains and Motifs , Two-Hybrid System TechniquesABSTRACT
Fertilization in flowering plants requires the temporal and spatial coordination of many developmental processes, including pollen production, anther dehiscence, ovule production, and pollen tube elongation. However, it remains elusive as to how this coordination occurs during reproduction. Here, we present evidence that endocytosis, involving heterotetrameric adaptor protein complex 2 (AP-2), plays a crucial role in fertilization. An Arabidopsis thaliana mutant ap2m displays multiple defects in pollen production and viability, as well as elongation of staminal filaments and pollen tubes, all of which are pivotal processes needed for fertilization. Of these abnormalities, the defects in elongation of staminal filaments and pollen tubes were partially rescued by exogenous auxin. Moreover, DR5rev:GFP (for green fluorescent protein) expression was greatly reduced in filaments and anthers in ap2m mutant plants. At the cellular level, ap2m mutants displayed defects in both endocytosis of N-(3-triethylammonium-propyl)-4-(4-diethylaminophenylhexatrienyl) pyridinium dibromide, a lypophilic dye used as an endocytosis marker, and polar localization of auxin-efflux carrier PIN FORMED2 (PIN2) in the stamen filaments. Moreover, these defects were phenocopied by treatment with Tyrphostin A23, an inhibitor of endocytosis. Based on these results, we propose that AP-2-dependent endocytosis plays a crucial role in coordinating the multiple developmental aspects of male reproductive organs by modulating cellular auxin level through the regulation of the amount and polarity of PINs.
Subject(s)
Adaptor Protein Complex 2/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis/growth & development , Arabidopsis/metabolism , Endocytosis , Pollen/growth & development , Arabidopsis/cytology , Arabidopsis/drug effects , Cell Membrane/drug effects , Cell Membrane/metabolism , Clathrin/metabolism , Cytosol/drug effects , Cytosol/metabolism , Endocytosis/drug effects , Fertilization/drug effects , Germination/drug effects , Green Fluorescent Proteins/metabolism , Indoleacetic Acids/pharmacology , Mutation/genetics , Pollen/cytology , Pollen/drug effects , Pollen/metabolism , Pollen Tube/drug effects , Pollen Tube/growth & development , Pollen Tube/metabolism , Protein Binding/drug effects , Protein Transport/drug effects , Seeds/drug effects , Seeds/growth & development , Seeds/metabolismABSTRACT
Clathrin-mediated endocytosis (CME) regulates many aspects of plant development, including hormone signaling and responses to environmental stresses. Despite the importance of this process, the machinery that regulates CME in plants is largely unknown. In mammals, the heterotetrameric adaptor protein complex-2 (AP-2) is required for the formation of clathrin-coated vesicles at the plasma membrane (PM). Although the existence of AP-2 has been predicted in Arabidopsis thaliana, the biochemistry and functionality of the complex is still uncharacterized. Here, we identified all the subunits of the Arabidopsis AP-2 by tandem affinity purification and found that one of the large AP-2 subunits, AP2A1, localized at the PM and interacted with clathrin. Furthermore, endocytosis of the leucine-rich repeat receptor kinase, brassinosteroid insensitive1 (BRI1), was shown to depend on AP-2. Knockdown of the two Arabidopsis AP2A genes or overexpression of a dominant-negative version of the medium AP-2 subunit, AP2M, impaired BRI1 endocytosis and enhanced the brassinosteroid signaling. Our data reveal that the CME machinery in Arabidopsis is evolutionarily conserved and that AP-2 functions in receptor-mediated endocytosis.
Subject(s)
Adaptor Protein Complex 2/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis/cytology , Arabidopsis/metabolism , Clathrin/metabolism , Endocytosis , Protein Kinases/metabolism , Adaptor Protein Complex 2/isolation & purification , Cell Membrane/metabolism , Plant Roots/metabolism , Protein Binding , Protein Transport , Signal TransductionABSTRACT
Multiple transcription factors (TFs) play essential roles in plants under abiotic stress, but how these multiple TFs cooperate in abiotic stress responses remains largely unknown. In this study, we provide evidence that the NAC (for NAM, ATAF1/2, and CUC2) TF ANAC096 cooperates with the bZIP-type TFs ABRE binding factor and ABRE binding protein (ABF/AREB) to help plants survive under dehydration and osmotic stress conditions. ANAC096 directly interacts with ABF2 and ABF4, but not with ABF3, both in vitro and in vivo. ANAC096 and ABF2 synergistically activate RD29A transcription. Our genome-wide gene expression analysis revealed that a major proportion of abscisic acid (ABA)-responsive genes are under the transcriptional regulation of ANAC096. We found that the Arabidopsis thaliana anac096 mutant is hyposensitive to exogenous ABA and shows impaired ABA-induced stomatal closure and increased water loss under dehydration stress conditions. Furthermore, we found the anac096 abf2 abf4 triple mutant is much more sensitive to dehydration and osmotic stresses than the anac096 single mutant or the abf2 abf4 double mutant. Based on these results, we propose that ANAC096 is involved in a synergistic relationship with a subset of ABFs for the transcriptional activation of ABA-inducible genes in response to dehydration and osmotic stresses.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/physiology , Basic-Leucine Zipper Transcription Factors/metabolism , Stress, Physiological , Abscisic Acid/metabolism , Abscisic Acid/pharmacology , Arabidopsis/drug effects , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Base Sequence , Basic-Leucine Zipper Transcription Factors/genetics , Cell Nucleus/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Dehydration , Gene Expression Regulation, Plant/drug effects , Germination/drug effects , Molecular Sequence Data , Mutation , Osmotic Pressure , Plants, Genetically Modified , Promoter Regions, Genetic , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
The retromer is involved in recycling lysosomal sorting receptors in mammals. A component of the retromer complex in Arabidopsis thaliana, vacuolar protein sorting 29 (VPS29), plays a crucial role in trafficking storage proteins to protein storage vacuoles. However, it is not known whether or how vacuolar sorting receptors (VSRs) are recycled from the prevacuolar compartment (PVC) to the trans-Golgi network (TGN) during trafficking to the lytic vacuole (LV). Here, we report that VPS29 plays an essential role in the trafficking of soluble proteins to the LV from the TGN to the PVC. maigo1-1 (mag1-1) mutants, which harbor a knockdown mutation in VPS29, were defective in trafficking of two soluble proteins, Arabidopsis aleurain-like protein (AALP):green fluorescent protein (GFP) and sporamin:GFP, to the LV but not in trafficking membrane proteins to the LV or plasma membrane or via the secretory pathway. AALP:GFP and sporamin:GFP in mag1-1 protoplasts accumulated in the TGN but were also secreted into the medium. In mag1-1 mutants, VSR1 failed to recycle from the PVC to the TGN; rather, a significant proportion was transported to the LV; VSR1 overexpression rescued this defect. Moreover, endogenous VSRs were expressed at higher levels in mag1-1 plants. Based on these results, we propose that VPS29 plays a crucial role in recycling VSRs from the PVC to the TGN during the trafficking of soluble proteins to the LV.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Vacuoles/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Protein Transport/genetics , Protein Transport/physiology , Vacuoles/genetics , Vesicular Transport Proteins/genetics , Vesicular Transport Proteins/metabolism , trans-Golgi Network/metabolismABSTRACT
The phytohormone abscisic acid (ABA) plays a critical role in various physiological processes, including adaptation to abiotic stresses. In Arabidopsis thaliana, ABA levels are increased both through de novo biosynthesis and via ß-glucosidase homolog1 (BG1)-mediated hydrolysis of Glc-conjugated ABA (ABA-GE). However, it is not known how many different ß-glucosidase proteins produce ABA from ABA-GE and how the multiple ABA production pathways are coordinated to increase ABA levels. Here, we report that a previously undiscovered ß-glucosidase homolog, BG2, produced ABA by hydrolyzing ABA-GE and plays a role in osmotic stress response. BG2 localized to the vacuole as a high molecular weight complex and accumulated to high levels under dehydration stress. BG2 hydrolyzed ABA-GE to ABA in vitro. In addition, BG2 increased ABA levels in protoplasts upon application of exogenous ABA-GE. Overexpression of BG2 rescued the bg1 mutant phenotype, as observed for the overexpression of NCED3 in bg1 mutants. Multiple Arabidopsis bg2 alleles with a T-DNA insertion in BG2 were more sensitive to dehydration and NaCl stress, whereas BG2 overexpression resulted in enhanced resistance to dehydration and NaCl stress. Based on these observations, we propose that, in addition to the de novo biosynthesis, ABA is produced in multiple organelles by organelle-specific ß-glucosidases in response to abiotic stresses.
Subject(s)
Abscisic Acid/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Cellulases/metabolism , Vacuoles/enzymology , Arabidopsis/enzymology , Arabidopsis Proteins/genetics , Cellulases/genetics , Desiccation , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/genetics , Osmosis/physiology , Sodium Chloride/pharmacologyABSTRACT
The aim of this study was to assess test-retest reliability and diagnostic validity of self-report instruments of depression and anxiety in autistic youth. Participants were 55 autistic youth aged 8-17 years presenting with depressive or anxiety symptoms. They were interviewed with the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS-PL) and completed the Children's Depression Inventory, Second Edition - Self Report Short (CDI 2:SR[S]) and the Revised Child Anxiety and Depression Scale (RCADS) twice, separated by a two-week interval. Test-retest reliability was measured with intraclass correlation coefficients (ICCs), and diagnostic validity was assessed using receiver operating characteristic (ROC) curves with the summary ratings on the K-SADS-PL as the criterion. The effect of participant characteristics was analyzed through a moderation analysis. Generalized anxiety (GAD) and social anxiety disorder (SOC) were the two most prevalent disorders in the sample. Test-retest reliability for most of the subscales was good (ICC = 0.74 - 0.87), with the exception of the RCADS obsessive-compulsive disorder (OCD) and GAD. The Adaptive Behavior conceptual score was a significant moderator of the reliability of the CDI 2:SR[S]. The ROC analysis suggested the RCADS SOC and the CDI 2:SR[S] to be good screening tools with inadequate specificity when appropriately sensitive cutoff scores are used. Optimal cutoff scores in this sample were lower than originally published. The findings suggest that autistic youth can provide stable reports of anxiety and depressive symptoms over time. Diagnostic validity varied according to the construct and instrument.
ABSTRACT
OBJECTIVE/BACKGROUND: Insomnia is common in children with autism spectrum disorder (ASD). We recently developed and validated the 21-item Pediatric Autism Insomnia Rating Scale (PAIRS). This report explores the associations and agreements between actigraphy and PAIRS. PARTICIPANTS METHODS: Children with ASD, with and without sleep problems, were assessed with a battery of parent-rated and clinician measures (N = 134). In a subset (n = 70), a wrist-worn actigraph measured sleep for five consecutive nights. Parents completed logs for scoring sleep intervals. Spearman correlations evaluated associations with the PAIRS and actigraphy indices (sleep onset latency = SOL, wake after sleep onset = WASO, total sleep time = TST, sleep efficiency = SE%). Agreements on "poor sleepers" based on PAIRS total score (≥33) and conventional thresholds for TST and SE% were evaluated with Cohen's Kappa and McNemar's test. RESULTS: Actigraphy data were averaged over 4.64 ± 0.68 nights in 70 children (mean age = 7.3 ± 2.9, 74.3 % male). There were no significant correlations between PAIRS and any actigraphy indices. On TST, 48.6 % (n = 34) and on SE% 52.9 % (n = 37) were classified as "poor sleepers" compared to 32.9 % (n = 23) on PAIRS (kappa = 0.11 for TST and 0.27 for SE%). P-values on McNemar's Chi square test for PAIRS with TST and with SE% were 0.072 and 0.011, respectfully. CONCLUSIONS: These results suggest that actigraphy and PAIRS do not agree. Actigraphy TST captures movement and an estimate of specific sleep parameters. PAIRS is a broader measure that incorporates sleep disturbance and sleep-related impairment.