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1.
Zhonghua Liu Xing Bing Xue Za Zhi ; 44(7): 1046-1053, 2023 Jul 10.
Article in Chinese | MEDLINE | ID: mdl-37482705

ABSTRACT

Objective: To assess the prevalence, risk factors and treatment of anemia in patients with chronic kidney disease (CKD). Methods: A descriptive method was used to analyze the prevalence and treatment of anemia in CKD patients based on regional health data in Yinzhou District of Ningbo during 2012-2018. The multivariate logistic regression analysis was used to identify independent influence factors of anemia in the CKD patients. Results: In 52 619 CKD patients, 15 639 suffered from by anemia (29.72%), in whom 5 461 were men (26.41%) and 10 178 were women (31.87%), and anemia prevalence was higher in women than in men, the difference was significant (P<0.001). The prevalence of anemia increased with stage of CKD (24.77% in stage 1 vs. 69.42% in stage 5, trend χ2 test P<0.001). Multivariate logistic regression analysis revealed that being women (aOR=1.57, 95%CI: 1.50-1.63), CKD stage (stage 2: aOR=1.10, 95%CI: 1.04-1.16;stage 3: aOR=2.28,95%CI: 2.12-2.44;stage 4: aOR=4.49,95%CI :3.79-5.32;stage 5: aOR=6.31,95%CI: 4.74-8.39), age (18-30 years old: aOR=2.40,95%CI: 2.24-2.57, 61-75 years old: aOR=1.35,95%CI:1.28-1.42, ≥76 years old: aOR=2.37,95%CI:2.20-2.55), BMI (<18.5 kg/m2:aOR=1.29,95%CI: 1.18-1.41;23.0-24.9 kg/m2:aOR=0.79,95%CI: 0.75-0.83;≥25.0 kg/m2:aOR=0.70,95%CI: 0.66-0.74), abdominal obesity (aOR=0.91, 95%CI: 0.86-0.96), chronic obstructive pulmonary disease (aOR=1.15, 95%CI: 1.09-1.22), cancer (aOR=3.03, 95%CI: 2.84-3.23), heart failure (aOR=1.44, 95%CI: 1.35-1.54) and myocardial infarction (aOR=1.54, 95%CI:1.16-2.04) were independent risk factors of anemia in CKD patients. Among stage 3-5 CKD patients with anemia, 12.03% received iron therapy, and 4.78% received treatment with erythropoiesis-stimulating agent (ESA) within 12 months after anemia was diagnosed. Conclusions: The prevalence of anemia in CKD patients was high in Yinzhou. However, the treatment rate of iron therapy and ESA were low. More attention should be paid to the anemia management and treatment in CKD patients.


Subject(s)
Anemia , Hematinics , Renal Insufficiency, Chronic , Male , Humans , Female , Adolescent , Young Adult , Adult , Middle Aged , Aged , Prevalence , Big Data , Anemia/epidemiology , Anemia/therapy , Renal Insufficiency, Chronic/complications , Renal Insufficiency, Chronic/epidemiology , Iron
2.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(2): 200-206, 2021 Feb 06.
Article in Chinese | MEDLINE | ID: mdl-34645180

ABSTRACT

Objective: To evaluate consistency between 2-fold serial and 4-fold serial diluted neutralization tests against Enterovirus A71 (EV-A71) in estimating titer, Geometric mean titer (GMT), seroprevalence, and seroincidence. Methods: Based on a prospective cohort of 1-9 years old children, mothers and infants established in Anhua County, Hunan Province, during 2013-2018, from which 92 participants with a total of 386 blood specimens were sampled and tested with a 2-fold serial dilution and a 4-fold serial dilution neutralization tests against EV-A71 at the same time. Agreement was estimated using the Bland-Altman method. Stratified analysis was conducted to estimate effect dilution approach on GMT, seroprevalence and seroincidence. Results: The mean difference (0.04, 95%CI:-0.02-0.10) between the two dilution approaches was not significant. However, the limits of agreement (LOA) (-1.12-1.21), with the 95% confidence interval of upper LOA (1.10-1.31) and of lower LOA (-1.22--1.02), significantly exceeded the Clinic accept interval (-1, 1) indicating insufficient agreement between the two approaches in practice. While the dilution approaches did not affect estimates of GMT of the total population and the positive population, and seroincidence with seroconversion only, the differences were 2, 6 and 2%, respectively (P>0.05). Estimates of seroincidence with at least 4-fold increase and seroconversion/4-fold increase were significantly higher using a 4-fold dilution neutralization test compared to the 2-fold dilution neutralization test with 8% (95%CI: 1%-12%) and 9% (95%CI: 1%-17%), respectively. Conclusion: The 2-dilution and 4-dilution neutralization tests yielded comparable results when estimating the population's GMT; however, the difference between the two is not negligible when assessing the seroincidence.


Subject(s)
Enterovirus A, Human , Enterovirus Infections , Enterovirus , Hand, Foot and Mouth Disease , Child , Child, Preschool , Female , Humans , Infant , Prospective Studies , Seroepidemiologic Studies
3.
Br J Cancer ; 110(1): 49-54, 2014 Jan 07.
Article in English | MEDLINE | ID: mdl-24253503

ABSTRACT

BACKGROUND: The objective of this study is to analyse the factors affecting late toxicity for nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT). METHODS: Seven hundred and eighty-nine consecutive NPC patients treated with IMRT at our centre from January 2003 to February 2008 were retrospectively analysed. Radiotherapy-related complications were categorised using the RTOG Late Radiation Morbidity Scoring Criteria and the Common Terminology Criteria for Adverse Events (Version 3.0). Two hundred and thirty-three patients were treated with IMRT alone (group 1) and 556 patients underwent cisplatin-based chemotherapy (group 2). RESULTS: Median follow-up was 65 months (range, 4-106 months). The 5-year major late toxicity rate was significantly greater in group 2 than group 1 (63.2% vs 42.0%, P<0.001). Multivariate analyses showed that N category, T category and chemotherapy were significant factors. The maximal dose (Dmax) to the temporal lobe was a significant factor affecting temporal lobe injury (TLI), with a hazard ratio of 1.26 (95% confidence interval (CI), 1.18-1.35; P<0.001) per 1-Gy increase. The 5-year TLI rate increased from 0.8% for 284 lobes with Dmax <65.77 Gy to 27.1% for 176 lobes with greater doses (P<0.001). Logistic regression showed that the hazard ratio attributed to the parotid gland mean dose was 1.36 (95% CI, 1.21-1.53; P<0.001) per 1-Gy increase. Chemotherapy was not a significant factor (P=0.211). CONCLUSION: With the application of IMRT, the incidence of radiation-related complications has been reduced except for TLI. The significant factors affecting the risk of TLI included T category, chemotherapy and Dmax.


Subject(s)
Nasopharyngeal Neoplasms/radiotherapy , Radiation Injuries/etiology , Adolescent , Adult , Aged , Carcinoma , China/epidemiology , Dose-Response Relationship, Radiation , Female , Humans , Male , Middle Aged , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms/epidemiology , Nasopharyngeal Neoplasms/pathology , Neoplasm Staging , Radiation Injuries/epidemiology , Radiotherapy, Intensity-Modulated/adverse effects , Radiotherapy, Intensity-Modulated/statistics & numerical data , Retrospective Studies , Young Adult
4.
Acta Otolaryngol ; 128(7): 732-8, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18568513

ABSTRACT

CONCLUSIONS: Significant difference in the incidence of mitochondrial DNA (mtDNA) mutations was found between the Chinese and USA populations. The identification of the mtDNA A1555G mutation in a large proportion of Chinese probands with nonsyndromic sensorineural hearing loss (NSHL) provides a molecular explanation for the high prevalence of aminoglycoside-induced deafness in China. OBJECTIVE: The aim was to characterize the audiological and genetic features of NSHL due to mutations in mtDNA. SUBJECTS AND METHODS: The mtDNA and audiogram analyses were performed in 498 NSHL patients (290 from China and 208 from the USA) with and without history of aminoglycoside exposure. A PCR and restriction enzyme digestion protocol was used for mutational screening and the European Workshop on Genetic Hearing Loss criteria were applied for audiological classification. RESULTS: All Chinese probands (15.5%) with mtDNA mutation were found to carry the homoplasmic mtDNA A1555G mutation, whereas four probands (1.9%) from the USA were found to carry the mtDNA A1555G and two (1%) had mtDNA G7444A. Approximately 63% of the probands with mtDNA mutations had post-lingual hearing loss and 56.8% of them had a medical history of exposure to aminoglycosides. Hearing losses are bilateral, sensorineural, and symmetric. The main audiogram shapes found were sloping.


Subject(s)
DNA, Mitochondrial/genetics , Hearing Loss, Sensorineural/physiopathology , Hearing/physiology , Mutation , Adolescent , Adult , Aged , Aged, 80 and over , Aminoglycosides/adverse effects , Asian People , Audiometry, Pure-Tone , Child , China/epidemiology , Deafness/chemically induced , Deafness/genetics , Deafness/physiopathology , Gene Frequency , Hearing Loss, Sensorineural/epidemiology , Hearing Loss, Sensorineural/genetics , Humans , Middle Aged , Polymerase Chain Reaction , United States/epidemiology , White People
6.
Evid Based Complement Alternat Med ; 1(3): 259-267, 2004 12.
Article in English | MEDLINE | ID: mdl-15841259

ABSTRACT

Agaricus blazei Murill is an edible fungus used in traditional medicine, which has various well-documented medicinal properties. In the present study, we investigated the effects of hemicellulase-derived mycelia extract (Agaricus blazei fraction H: ABH) on the immune system. First, we examined the cytokine-inducing activity of ABH on human peripheral mononuclear cells (PBMC). The results indicated that ABH induced expression of IL-12, a cytokine known to be a critical regulator of cellular immune responses. Flow cytometric analysis demonstrated the induction of IL-12 production by the CD14-positive cell population, consisting of monocytes/macrophages (Mo/Mphi). Furthermore, the elimination of Mo/Mphi attenuated IL-12 production in PBMC. ABH-induced IL-12 production was inhibited by anti-CD14 and anti-TLR4 antibodies but not by anti-TLR2 antibody. The activity of ABH was not inhibited by polymyxin B, while the activity of lipopolysaccharide used as a reference was inhibited. Oral administration of ABH enhanced natural killer (NK) activity in the spleen. These findings suggest that ABH activated Mo/Mphi in a manner dependent on CD14/TLR4 and NK activity.

7.
Plant Cell ; 13(12): 2589-607, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11752374

ABSTRACT

An expressed sequence tag-based microarray was used to profile genome expression underlying light control of Arabidopsis development. Qualitatively similar gene expression profiles were observed among seedlings grown in different light qualities, including far-red, red, and blue light, which are mediated primarily by phytochrome A, phytochrome B, and the cryptochromes, respectively. Furthermore, light/dark transitions also triggered similar differential genome expression profiles. Most light treatments also resulted in distinct expression profiles in small fractions of the expressed sequence tags examined. The similarly regulated genes in all light conditions were estimated to account for approximately one-third of the genome, with three-fifths upregulated and two-fifths downregulated by light. Analysis of those light-regulated genes revealed more than 26 cellular pathways that are regulated coordinately by light. Thus, light controls Arabidopsis development through coordinately regulating metabolic and regulatory pathways.


Subject(s)
Arabidopsis/growth & development , Drosophila Proteins , Eye Proteins , Genome, Plant , Photoreceptor Cells, Invertebrate , Plant Proteins/genetics , Transcription Factors , Arabidopsis/genetics , Arabidopsis/radiation effects , Arabidopsis Proteins , Cryptochromes , Expressed Sequence Tags , Flavoproteins/genetics , Flavoproteins/radiation effects , Gene Expression Regulation, Developmental/radiation effects , Gene Expression Regulation, Plant/radiation effects , Light , Oligonucleotide Array Sequence Analysis , Photoreceptor Cells/radiation effects , Phytochrome/genetics , Phytochrome/radiation effects , Phytochrome A , Phytochrome B , Plant Proteins/radiation effects , Plant Shoots/genetics , Plant Shoots/growth & development , Plant Shoots/radiation effects , Receptors, G-Protein-Coupled
8.
Plant Cell ; 13(11): 2393-407, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11701877

ABSTRACT

The COP9 signalosome is a highly conserved protein complex initially identified as a repressor of photomorphogenesis. Here, we report that subunit 6 of the Arabidopsis COP9 signalosome is encoded by a family of two genes (CSN6A and CSN6B) located on chromosomes V and IV, respectively. The CSN6A and CSN6B proteins share 87% amino acid identity and contain a MPR1p and PAD1p N-terminal (MPN) domain at the N-terminal region. The CSN6 proteins share homology with CSN5 and belong to the Mov34 superfamily of proteins. CSN6 proteins present only in the complex form and coimmunoprecipitate with other known subunits of the COP9 signalosome. Partial loss-of-function strains of the COP9 signalosome created by antisense and cosuppression with CSN6A exhibit diverse developmental defects, including homeotic organ transformation, symmetric body organization, and organ boundary definition. Protein blot analysis revealed that the defective plants accumulate significant amounts of ubiquitinated proteins, supporting the conclusion that the COP9 signalosome regulates multifaceted developmental processes through its involvement in ubiquitin/proteasome-mediated protein degradation.


Subject(s)
Arabidopsis Proteins , Arabidopsis/genetics , Plant Proteins/genetics , Proteins/genetics , Amino Acid Sequence , Arabidopsis/classification , COP9 Signalosome Complex , Cloning, Molecular , DNA, Complementary/genetics , Humans , Molecular Sequence Data , Multigene Family , Multiprotein Complexes , Peptide Hydrolases , Phenotype , Phylogeny , Plant Proteins/chemistry , Plant Proteins/metabolism , Plants, Genetically Modified/genetics , Protein Kinases/chemistry , Protein Kinases/genetics , Protein Kinases/metabolism , Protein Subunits , Saccharomyces cerevisiae/genetics , Sequence Alignment , Sequence Homology, Amino Acid , Transformation, Genetic
9.
Development ; 128(21): 4277-88, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11684663

ABSTRACT

The COP9 signalosome is a highly conserved eight-subunit protein complex initially defined as a repressor of photomorphogenic development in Arabidopsis. It has recently been suggested that the COP9 signalosome directly interacts and regulates SCF type E3 ligases, implying a key role in ubiquitin-proteasome mediated protein degradation. We report that Arabidopsis FUS11 gene encodes the subunit 3 of the COP9 signalosome (CSN3). The fus11 mutant is defective in the COP9 signalosome and accumulates significant amount of multi-ubiquitinated proteins. The same mutant is specifically impaired in the 26S proteasome-mediated degradation of HY5 but not PHYA, indicating a selective involvement in protein degradation. Reduction-of-function transgenic lines of CSN3 produced through gene co-suppression also accumulate multi-ubiquitinated proteins and exhibit diverse developmental defects. This result substantiates a hypothesis that the COP9 signalosome is involved in multifaceted developmental processes through regulating proteasome-mediated protein degradation.


Subject(s)
Arabidopsis/genetics , Gene Expression Regulation, Plant , Protein Kinases/genetics , Proteins/genetics , Proteins/metabolism , Amino Acid Sequence , Arabidopsis/growth & development , Arabidopsis Proteins , Base Sequence , COP9 Signalosome Complex , Chromosome Mapping , Cloning, Molecular , Molecular Sequence Data , Multiprotein Complexes , Mutation , Nuclear Proteins , Peptide Hydrolases , Plant Leaves/growth & development , Plant Proteins/metabolism , Plant Structures/genetics , Plant Structures/growth & development , Protein Kinases/metabolism , Sequence Homology, Amino Acid , Substrate Specificity , Ubiquitin/metabolism
11.
Trends Cell Biol ; 11(10): 420-6, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11567875

ABSTRACT

The COP9 signalosome is an evolutionarily conserved multiprotein complex that was first identified as an essential complex that represses light-regulated development in Arabidopsis. The COP9 signalosome has similarity to the lid of the 19S regulatory particle of the 26S proteasome and has recently been shown to interact with SCF-type E3 ubiquitin ligases. Although its precise role in the process of protein degradation remains to be established, the COP9 signalosome is a positive regulator of E3 ubiquitin ligases that functions at least in part by mediating the deconjugation of the NEDD8/RUB-modification from the cullin subunit of SCF-type E3 complexes. Here, we discuss these recent findings, which add an additional component to the biology of substrate-specific protein degradation.


Subject(s)
Proteasome Endopeptidase Complex , Proteins/metabolism , Proteins/physiology , Ubiquitins/metabolism , Animals , Arabidopsis , Arabidopsis Proteins , COP9 Signalosome Complex , Drosophila/metabolism , Drosophila Proteins , Humans , Ligases/metabolism , Models, Biological , Multiprotein Complexes , NEDD8 Protein , Peptide Hydrolases/chemistry , Peptide Hydrolases/metabolism , Protein Structure, Tertiary , Protein Subunits , Proteins/chemistry , Proteins/genetics , Schizosaccharomyces , Signal Transduction , Ubiquitin-Protein Ligases
12.
Science ; 294(5540): 154-8, 2001 Oct 05.
Article in English | MEDLINE | ID: mdl-11509693

ABSTRACT

Arabidopsis seedling photomorphogenesis involves two antagonistically acting components, COP1 and HY5. COP1 specifically targets HY5 for degradation via the 26S proteasome in the dark through their direct physical interaction. Little is known regarding how light signals perceived by photoreceptors are transduced to regulate COP1. Arabidopsis has two related cryptochromes (cry1 and cry2) mediating various blue/ultraviolet-A light responses. Here we show that both photoactivated cryptochromes repress COP1 activity through a direct protein-protein contact and that this direct regulation is primarily responsible for the cryptochrome-mediated blue light regulation of seedling photomorphogenic development and genome expression profile.


Subject(s)
Arabidopsis Proteins , Arabidopsis/growth & development , Arabidopsis/metabolism , Carrier Proteins/metabolism , Drosophila Proteins , Eye Proteins , Flavoproteins/metabolism , Light , Photoreceptor Cells, Invertebrate , Plant Proteins/metabolism , Ubiquitin-Protein Ligases , Arabidopsis/genetics , Basic-Leucine Zipper Transcription Factors , Carrier Proteins/chemistry , Carrier Proteins/genetics , Cell Nucleus/metabolism , Crosses, Genetic , Cryptochromes , Darkness , Expressed Sequence Tags , Flavoproteins/genetics , Gene Expression Profiling , Gene Expression Regulation, Plant , Genes, Plant , Morphogenesis , Mutation , Nuclear Proteins/metabolism , Oxidation-Reduction , Phenotype , Plant Proteins/chemistry , Plant Proteins/genetics , Plants, Genetically Modified , Precipitin Tests , Protein Binding , Protein Structure, Tertiary , Receptors, G-Protein-Coupled , Recombinant Fusion Proteins/metabolism , Signal Transduction
13.
Plant Cell ; 13(7): 1639-52, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11449056

ABSTRACT

Plant heterotrimeric G-proteins have been implicated in a number of signaling processes. However, most of these studies are based on biochemical or pharmacological approaches. To examine the role of heterotrimeric G-proteins in plant development, we generated transgenic Arabidopsis expressing the Galpha subunit of the heterotrimeric G-protein under the control of a glucocorticoid-inducible promoter. With the conditional overexpression of either the wild type or a constitutively active version of Arabidopsis Galpha, transgenic seedlings exhibited a hypersensitive response to light. This enhanced light sensitivity was more exaggerated in a relatively lower intensity of light and was observed in white light as well as far-red, red, and blue light conditions. The enhanced responses in far-red and red light required functional phytochrome A and phytochrome B, respectively. Furthermore, the response to far-red light depended on functional FHY1 but not on FIN219 and FHY3. This dependence on FHY1 indicates that the Arabidopsis Galpha protein may act only on a discrete branch of the phytochrome A signaling pathway. Thus, our results support the involvement of a heterotrimeric G-protein in the light regulation of Arabidopsis seedling development.


Subject(s)
Arabidopsis Proteins , Arabidopsis/physiology , GTP-Binding Protein alpha Subunits , Heterotrimeric GTP-Binding Proteins/physiology , Hypocotyl/growth & development , Arabidopsis/embryology , Arabidopsis/genetics , Cell Differentiation , Cell Division , Gene Expression Regulation, Plant , Heterotrimeric GTP-Binding Proteins/genetics , Hypocotyl/radiation effects , Light , Phenotype , Phytochrome/physiology , Plant Proteins , Plants, Genetically Modified , Promoter Regions, Genetic , RNA, Plant , Receptors, Glucocorticoid/biosynthesis , Receptors, Glucocorticoid/metabolism , Signal Transduction , Transgenes
14.
Science ; 292(5520): 1379-82, 2001 May 18.
Article in English | MEDLINE | ID: mdl-11337587

ABSTRACT

The COP9 signalosome is an evolutionary conserved multiprotein complex of unknown function that acts as a negative regulator of photomorphogenic seedling development in Arabidopsis. Here, we show that plants with reduced COP9 signalosome levels had decreased auxin response similar to loss-of-function mutants of the E3 ubiquitin ligase SCFTIR1. Furthermore, we found that the COP9 signalosome and SCFTIR1 interacted in vivo and that the COP9 signalosome was required for efficient degradation of PSIAA6, a candidate substrate of SCFTIR1. Thus, the COP9 signalosome may play an important role in mediating E3 ubiquitin ligase-mediated responses.


Subject(s)
Arabidopsis/drug effects , Indoleacetic Acids/pharmacology , Ligases/metabolism , Plant Proteins/metabolism , Proteins/metabolism , Arabidopsis/enzymology , Arabidopsis/genetics , Arabidopsis/growth & development , Brassica , COP9 Signalosome Complex , Darkness , Gene Expression Regulation, Plant/drug effects , Genes, Reporter/genetics , Ligases/genetics , Multiprotein Complexes , Mutation/genetics , Pisum sativum , Peptide Hydrolases , Phenotype , Plant Proteins/genetics , Plant Roots/drug effects , Plant Roots/enzymology , Plant Roots/genetics , Plant Roots/growth & development , Plants, Genetically Modified , Precipitin Tests , Protein Binding , Protein Biosynthesis , Protein Subunits , Proteins/genetics , RNA, Antisense/genetics , RNA, Plant/genetics , RNA, Plant/metabolism , Two-Hybrid System Techniques , Ubiquitin-Protein Ligases
15.
Mol Biol Cell ; 12(2): 383-92, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11179422

ABSTRACT

In Arabidopsis seedlings and cauliflower florets, Rpn6 (a proteasome non-ATPase regulatory subunit) was found in two distinct protein complexes of approximately 800 and 500 kDa, respectively. The large complex likely represents the proteasome 19S regulator particle (RP) because it displays the expected subunit composition and all characteristics. The small complex, designated PR500, shares at least three subunits with the "lid" subcomplex of 19S RP and is loosely associated with an hsp70 protein. In Arabidopsis COP9 signalosome mutants, PR500 was specifically absent or reduced to an extent that correlates with the severity of the mutations. Furthermore, PR500 was also diminished in response to potential protein-misfolding stresses caused by the heat shock and canavanine treatment. Immunofluorescence studies suggest that PR500 has a distinct localization pattern and is enriched in specific nuclear foci. We propose that PR500 may be evolved in higher plants to cope with the frequently encountered environmental stresses.


Subject(s)
Arabidopsis/physiology , Cysteine Endopeptidases/metabolism , Multienzyme Complexes/metabolism , Plant Proteins/metabolism , Arabidopsis/drug effects , Brassica/metabolism , COP9 Signalosome Complex , Canavanine/pharmacology , Cell Nucleus/metabolism , HSP70 Heat-Shock Proteins/metabolism , Heat-Shock Response , Multiprotein Complexes , Mutation , Peptide Hydrolases , Plant Proteins/genetics , Proteasome Endopeptidase Complex , Proteins/genetics , Proteins/metabolism
16.
EMBO J ; 20(1-2): 118-27, 2001 Jan 15.
Article in English | MEDLINE | ID: mdl-11226162

ABSTRACT

Arabidopsis COP1 is a photomorphogenesis repressor capable of directly interacting with the photomorphogenesis-promoting factor HY5. This interaction between HY5 and COP1 results in targeted deg radation of HY5 by the 26S proteasome. Here we characterized the WD40 repeat domain-mediated interactions of COP1 with HY5 and two new proteins. Mutational analysis of those interactive partners revealed a conserved motif responsible for the interaction with the WD40 domain. This novel motif, with the core sequence V-P-E/D-φ-G (φ = hydrophobic residue) in conjunction with an upstream stretch of 4-5 negatively charged residues, interacts with a defined surface area of the ss-propeller assembly of the COP1 WD40 repeat domain through both hydrophobic and ionic interactions. Several residues in the COP1 WD40 domain that are critical for the interaction with this motif have been revealed. The fact that point mutations either in the COP1 WD40 domain or in the HY5 motif that abolish the interaction between COP1 and HY5 in yeast result in a dramatic reduction of HY5 degradation in transgenic plants validates the biological significance of this defined interaction.


Subject(s)
Arabidopsis Proteins , Arabidopsis/physiology , Carrier Proteins/chemistry , Carrier Proteins/metabolism , Plant Proteins/chemistry , Plant Proteins/metabolism , Proteasome Endopeptidase Complex , Ubiquitin-Protein Ligases , Amino Acid Sequence , Arabidopsis/genetics , Binding Sites , Carrier Proteins/genetics , Cloning, Molecular , Computer Graphics , Cysteine , Models, Molecular , Molecular Sequence Data , Mutagenesis , Mutagenesis, Site-Directed , Peptide Hydrolases/metabolism , Plant Proteins/genetics , Plants, Genetically Modified , Protein Structure, Secondary , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Repetitive Sequences, Amino Acid , Repressor Proteins/chemistry , Repressor Proteins/metabolism , Saccharomyces cerevisiae/genetics , Sequence Alignment , Sequence Deletion , Sequence Homology, Amino Acid
17.
J Biol Chem ; 276(12): 9322-9, 2001 Mar 23.
Article in English | MEDLINE | ID: mdl-11124253

ABSTRACT

Nuclear import of proteins that contain classical nuclear localization signals (NLS) is initiated by importin alpha, a protein that recognizes and binds to the NLS in the cytoplasm. In this paper, we have cloned a cDNA for a novel importin alpha homologue from rice which is in addition to our previously isolated rice importin alpha1a and alpha2, and we have named it rice importin alpha1b. In vitro binding and nuclear import assays using recombinant importin alpha1b protein demonstrate that rice importin alpha1b functions as a component of the NLS-receptor in plant cells. Analysis of the transcript levels for all three rice importin alpha genes revealed that the genes were not only differentially expressed but that they also responded to dark-adaptation in green leaves. Furthermore, we also show that the COP1 protein bears a bipartite-type NLS and its nuclear import is mediated preferentially by the rice importin alpha1b. These data suggest that each of the different rice importin alpha proteins carry distinct groups of nuclear proteins, such that multiple isoforms of importin alpha contribute to the regulation of plant nuclear protein transport.


Subject(s)
Arabidopsis Proteins , Carrier Proteins/metabolism , Nuclear Localization Signals , Nuclear Proteins/genetics , Oryza/genetics , Plant Proteins/metabolism , Ubiquitin-Protein Ligases , Amino Acid Sequence , Base Sequence , Carrier Proteins/chemistry , Cell Nucleus/metabolism , Cloning, Molecular , DNA, Complementary , Digitonin/pharmacology , HeLa Cells , Humans , Karyopherins , Molecular Sequence Data , Nuclear Proteins/metabolism , Plant Proteins/chemistry , Protein Binding , Protein Transport , RNA, Messenger/genetics , Sequence Homology, Amino Acid
20.
EMBO J ; 19(18): 4997-5006, 2000 Sep 15.
Article in English | MEDLINE | ID: mdl-10990463

ABSTRACT

Arabidopsis HY5 is a bZIP transcription factor that promotes photomorphogenesis. Previous studies suggested that COP1, a negative regulator of photomorphogenesis, directly interacts with nuclear HY5 and targets it for proteasome-mediated degradation. Light negatively regulates the nuclear level of COP1 and thus permits HY5 accumulation. Here we report that HY5 abundance peaks in early seedling development, consistent with its role in promoting photomorphogenesis. HY5 acts exclusively within a complex and exists in two isoforms, resulting from phosphorylation within its COP1 binding domain by a light- regulated kinase activity. Unphosphorylated HY5 shows stronger interaction with COP1, is the preferred substrate for degradation, has higher affinity to target promoters and is physiologically more active than the phosphorylated version. Therefore, HY5 phosphorylation provides an added level of light-mediated regulation of HY5 stability and activity besides nuclear COP1 levels. Regulated HY5 phosphorylation not only provides abundant and physiologically more active unphosphorylated HY5 in the light, but also helps to maintain a small pool of less active phosphorylated HY5 in the dark, which could be essential for a rapid initial response during dark-to-light transition.


Subject(s)
Arabidopsis Proteins , Arabidopsis/chemistry , Carrier Proteins/metabolism , Nuclear Proteins/chemistry , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Plant Proteins/metabolism , Ubiquitin-Protein Ligases , Amino Acid Sequence , Basic-Leucine Zipper Transcription Factors , Binding Sites , Blotting, Western , Carrier Proteins/chemistry , Casein Kinase II , Cell Nucleus/metabolism , Chromatography, Gel , Glutathione Transferase/metabolism , Light , Molecular Sequence Data , Phosphorylation , Plant Proteins/chemistry , Plants, Genetically Modified , Precipitin Tests , Promoter Regions, Genetic , Protein Isoforms , Protein Serine-Threonine Kinases/metabolism , Protein Structure, Tertiary , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Sequence Homology, Amino Acid , Time Factors , Tissue Distribution , Transcription Factors/chemistry , Transcription Factors/metabolism , Transgenes , Two-Hybrid System Techniques
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