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1.
Plant J ; 67(4): 608-21, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21518052

RESUMEN

LOV KELCH PROTEIN2 (LKP2), ZEITLUPE (ZTL)/LOV KELCH PROTEIN1 (LKP1) and FLAVIN-BINDING KELCH REPEAT F-BOX1 (FKF1) constitute a family of Arabidopsis F-box proteins that regulate the circadian clock. Over-expression of LKP2 or ZTL causes arrhythmicity of multiple clock outputs under constant light and in constant darkness. Here, we show the significance of LKP2 and ZTL in the photoperiodic control of flowering time in Arabidopsis. In plants over-expressing LKP2, CO and FT expression was down-regulated under long-day conditions. LKP2 and ZTL physically interacted with FKF1, which was recruited from the nucleus into cytosolic speckles. LKP2 and ZTL inhibited the interaction of FKF1 with CYCLING DOF FACTOR 1, a ubiquitination substrate for FKF1 that is localized in the nucleus. The Kelch repeat regions of LKP2 and ZTL were sufficient for their physical interaction with FKF1 and translocation of FKF1 to the cytoplasm. Over-expression of LKP2 Kelch repeats induced late flowering under long-day conditions. lkp2 ztl double mutant plants flowered earlier than wild-type plants under short-day (non-inductive) conditions, and both CO and FT expression levels were up-regulated in the double mutant plants. The early flowering of lkp2 ztl was dependent on FKF1. LKP2, ZTL or both affected the accumulation of FKF1 protein during the early light period. These results indicate that an important role of LKP2 and ZTL in the photoperiodic pathway is repression of flowering under non-inductive conditions, and this is dependent on FKF1.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Arabidopsis/ultraestructura , Regulación de la Expresión Génica de las Plantas/fisiología , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Núcleo Celular/metabolismo , Citosol/metabolismo , Regulación hacia Abajo , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Flores/genética , Flores/fisiología , Prueba de Complementación Genética , Fenotipo , Fotoperiodo , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Brotes de la Planta/genética , Brotes de la Planta/fisiología , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Plantas Modificadas Genéticamente/fisiología , Plantas Modificadas Genéticamente/ultraestructura , Eliminación de Secuencia
2.
Proc Natl Acad Sci U S A ; 104(49): 19625-30, 2007 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-18003911

RESUMEN

A blue light (BL) receptor was discovered in stramenopile algae Vaucheria frigida (Xanthophyceae) and Fucus distichus (Phaeophyceae). Two homologs were identified in Vaucheria; each has one basic region/leucine zipper (bZIP) domain and one light-oxygen-voltage (LOV)-sensing domain. We named these chromoproteins AUREOCHROMEs (AUREO1 and AUREO2). AUREO1 binds flavin mononucleotide via its LOV domain and forms a 390-nm-absorbing form, indicative of formation of a cysteinyl adduct to the C(4a) carbon of the flavin mononucleotide upon BL irradiation. The adduct decays to the ground state in approximately 5 min. Its bZIP domain binds the target sequence TGACGT. The AUREO1 target binding was strongly enhanced by BL treatment, implying that AUREO1 functions as a BL-regulated transcription factor. The function of AUREO1 as photoreceptor for BL-induced branching is elucidated through RNAi experiments. RNAi of AUREO2 unexpectedly induces sex organ primordia instead of branches, implicating AUREO2 as a subswitch to initiate development of a branch, but not a sex organ. AUREO sequences are also found in the genome of the marine diatom Thalassiosira pseudonana (Bacillariophyceae), but are not present in green plants. AUREOCHROME therefore represents a BL receptor in photosynthetic stramenopiles.


Asunto(s)
Diatomeas/crecimiento & desarrollo , Fucus/crecimiento & desarrollo , Morfogénesis , Phaeophyceae/crecimiento & desarrollo , Células Fotorreceptoras/fisiología , Secuencia de Aminoácidos , Diatomeas/genética , Fucus/genética , Regulación de la Expresión Génica , Datos de Secuencia Molecular , Morfogénesis/genética , Phaeophyceae/genética , Células Fotorreceptoras/química , Células Fotorreceptoras/efectos de los fármacos , Estructura Terciaria de Proteína , Interferencia de ARN , Transcripción Genética
3.
FEBS Lett ; 580(13): 3282-6, 2006 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-16697373

RESUMEN

Nucleoside diphosphate kinase (NDK) is an ubiquitous enzyme with the function of a signal transducer. In Neurospora crassa, an ndk-1(P72H) mutant carrying the point mutation Pro72His was isolated. We found that ndk-1(P72H) showed hypersensitivity to oxidative and heat stress and a decrease in the levels of catalase (Cat)-1 and -3 induced by oxidative, heat stress and illumination compared with wild type (Wt). We found, by conducting a yeast two-hybrid assay, that Cat-1 interacted with NDK-1. NDK-1 was suggested to control Cat-1 and Cat-3 at the post-transcriptional level in response to heat, oxidative stress and light.


Asunto(s)
Catalasa/metabolismo , Proteínas Fúngicas/metabolismo , Neurospora crassa/enzimología , Nucleósido-Difosfato Quinasa/metabolismo , Proteínas Fúngicas/genética , Calor , Inmunoprecipitación , Luz , Neurospora crassa/efectos de los fármacos , Neurospora crassa/efectos de la radiación , Nucleósido-Difosfato Quinasa/genética , Estrés Oxidativo , Mapeo de Interacción de Proteínas , Técnicas del Sistema de Dos Híbridos , Agua/farmacología
5.
FEBS Lett ; 584(11): 2393-6, 2010 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-20399775

RESUMEN

Potato tuberization is induced under short-day conditions and repressed under long-day conditions. In this study, we produced transgenic potatoes overexpressing either Arabidopsis thaliana LOV KELCH PROTEIN 2 (35S:LKP2) or CONSTANS fused with a transcription repressor motif (35S:CO-Rep). In an in vitro tuberization assay, the average number of tubers per plant was greater in 35S:LKP2 plants than in vector-control plants, but lower in 35S:CO-Rep plants. Under long-day conditions in soil, all 35S:LKP2 plants tuberized, whereas most control plants and 35S:CO-Rep plants did not. These results suggest genes involved in flowering time regulation can be used to control potato tuber production.


Asunto(s)
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fenómenos Bioquímicos , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Proteínas de Arabidopsis/fisiología
6.
Plant Signal Behav ; 3(11): 966-8, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19704421

RESUMEN

The light, oxygen or voltage (LOV) domain belongs to the Per-ARNT-Sim (PAS) superfamily of domains, and functions with the flavin chromophore as a module for sensing blue light in plants and fungi. The Arabidopsis thaliana PAS/LOV proteins (PLPs), of unknown function, possess an N-terminal PAS domain and a C-terminal LOV domain. Our recent analysis using yeast two-hybrid and Escherichia coli protein production systems reveals that the interactions of Arabidopsis PLPs with several proteins diminish under blue light illumination and that the PLP LOV domain may bind to a flavin chromophore. These results suggest that PLP functions as a blue light receptor. Homologs of PLP exist in rice, tomato and moss. The LOV domains of these PLP homologs form a distinct group in phylogenetic analysis. These facts suggest that PLP belongs to a new class of plant blue light receptor.

7.
J Plant Res ; 121(1): 97-105, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17982713

RESUMEN

The light, oxygen, or voltage (LOV) domain that belongs to the Per-ARNT-Sim (PAS) domain superfamily is a blue light sensory module. The Arabidopsis thaliana PAS/LOV PROTEIN (PLP) gene encodes three putative blue light receptor proteins, PLPA, PLPB, and PLPC, because of its mRNA splicing variation. PLPA and PLPB each contain one PAS domain at the N-terminal region and one LOV domain at the C-terminal region, while the LOV domain is truncated in PLPC. RNA gel blot analysis showed that PLP mRNA was markedly expressed after exposure to salt or dehydration stress. Yeast two-hybrid screening led to the isolation of VITAMIN C DEFECTIVE 2 (VTC2), VTC2-LIKE (VTC2L), and BEL1-LIKE HOMEODOMAIN 10 proteins (BLH10A and BLH10B) as PLP-interacting proteins. The molecular interaction of PLPA with VTC2L, BLH10A or BLH10B, and that of PLPB with VTC2L were diminished when yeasts were grown under blue light illumination. Furthermore, the possible binding of flavin chromophore to PLPA and PLPB was demonstrated. These results imply that the LOV domain of PLPA and PLPB functions as a blue light sensor, and suggest the applicability of these interactions to blue light-dependent switching in transcriptional regulation in yeast or other organisms.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Luz , Secuencia de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/efectos de la radiación , Regulación de la Expresión Génica de las Plantas/fisiología , Datos de Secuencia Molecular , Unión Proteica/efectos de la radiación , Isoformas de Proteínas , Estructura Terciaria de Proteína
8.
Plant Physiol ; 148(2): 829-42, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18715957

RESUMEN

Chloroplasts change their intracellular distribution in response to light intensity. Previously, we isolated the chloroplast unusual positioning1 (chup1) mutant of Arabidopsis (Arabidopsis thaliana). This mutant is defective in normal chloroplast relocation movement and shows aggregation of chloroplasts at the bottom of palisade mesophyll cells. The isolated gene encodes a protein with an actin-binding motif. Here, we used biochemical analyses to determine the subcellular localization of full-length CHUP1 on the chloroplast outer envelope. A CHUP1-green fluorescent protein (GFP) fusion, which was detected at the outermost part of mesophyll cell chloroplasts, complemented the chup1 phenotype, but GFP-CHUP1, which was localized mainly in the cytosol, did not. Overexpression of the N-terminal hydrophobic region (NtHR) of CHUP1 fused with GFP (NtHR-GFP) induced a chup1-like phenotype, indicating a dominant-negative effect on chloroplast relocation movement. A similar pattern was found in chloroplast OUTER ENVELOPE PROTEIN7 (OEP7)-GFP transformants, and a protein containing OEP7 in place of NtHR complemented the mutant phenotype. Physiological analyses of transgenic Arabidopsis plants expressing truncated CHUP1 in a chup1 mutant background and cytoskeletal inhibitor experiments showed that the coiled-coil region of CHUP1 anchors chloroplasts firmly on the plasma membrane, consistent with the localization of coiled-coil GFP on the plasma membrane. Thus, CHUP1 localization on chloroplasts, with the N terminus inserted into the chloroplast outer envelope and the C terminus facing the cytosol, is essential for CHUP1 function, and the coiled-coil region of CHUP1 prevents chloroplast aggregation and participates in chloroplast relocation movement.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Cloroplastos/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Microfilamentos/metabolismo , Secuencia de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Cloroplastos , ADN Complementario/genética , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Proteínas de la Membrana/genética , Proteínas de Microfilamentos/genética , Datos de Secuencia Molecular , Mutación , Fenotipo , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/fisiología , Plásmidos , ARN Mensajero/genética , ARN de Planta/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Alineación de Secuencia , Transformación Genética
9.
Plant Cell Rep ; 26(6): 815-21, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17219103

RESUMEN

The transcription factor CONSTANS (CO) plays a central role in the photoperiod pathway by integrating the circadian clock and light signals into a control for flowering time. CO induces flowering locus T (FT) and suppressor of overexpression of CO 1 (SOC1) expression, and thereby promotes flowering. The ethylene-responsive element-binding factor associated amphiphilic repression (EAR) motif was used to construct a CONSTANS-EAR motif repressor gene (CO-Rep), which was overexpressed in Arabidopsis under the control of the Cauliflower mosaic virus 35S promoter in order to test its potential for flowering time regulation under inductive long day conditions. Morphological abnormalities in the root and cotyledon formation, and dwarfness were frequently seen in the transgenic plants, suggesting that the proper timing, location, and/or level of CO-Rep expression are important for its application. In morphologically normal CO-Rep plants, both bolting and flowering times under inductive long day conditions were twofold greater than in controls. As a result of the delay in flowering, rosette leaf number at bolting, and rosette and cauline leaf number at flowering increased significantly in CO-Rep plants. RT-PCR analysis demonstrated that FT expression was greatly reduced in the CO-Rep plants, while endogenous CO and SOC1 expression levels were not markedly affected. Conservation of CO among a diverse range of plant species, and its involvement in a variety of photoperiodic responses including flowering, suggests a high potential for use of CO-Rep to manipulate such responses in an agronomically desirable manner.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Quimera , Proteínas de Unión al ADN/genética , Flores/crecimiento & desarrollo , Factores de Transcripción/genética , Agrobacterium tumefaciens/fisiología , Arabidopsis/fisiología , Secuencia de Bases , Cartilla de ADN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transformación Bacteriana
10.
FEMS Yeast Res ; 4(7): 737-44, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15093777

RESUMEN

A partial cDNA fragment of the Cryptococcus neoformans homologue of the main cell cycle control gene CDC28/cdc2 was isolated using degenerate primer RT-PCR. A subsequent search in the C. neoformans genome database identified several sequences similar to CDC28/cdc2. A part of the sequence which showed the highest similarity to CDC28/cdc2 turned out to be identical to the partial cyclin-dependent kinase (Cdk) cDNA fragment isolated by degenerate RT-PCR. The full-length coding region of this Cdk homologue was amplified by RT-PCR using primers designed to target regions around start and stop codons, and the gene was named CnCdk1. To determine its function, an analysis of deduced amino acid sequence of the CnCdk1 was performed and its ability to rescue Saccharomyces cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2- CnCdk1 construct exhibited growth at 36.5 degrees C in galactose-raffinose medium, but not in glucose medium. Results of the sequence analysis and the fact that CnCdk1 is able to complement the S. cerevisiae cdc28-ts mutation support its assumed role as the CDC28/cdc2 homologue in C. neoformans.


Asunto(s)
Quinasas CDC2-CDC28/genética , Quinasas CDC2-CDC28/aislamiento & purificación , Cryptococcus neoformans/enzimología , Cryptococcus neoformans/genética , Secuencia de Aminoácidos , Secuencia de Bases , Proteína Quinasa CDC2/genética , Proteína Quinasa CDC2/metabolismo , Quinasas CDC2-CDC28/metabolismo , Proteína Quinasa CDC28 de Saccharomyces cerevisiae/genética , Proteína Quinasa CDC28 de Saccharomyces cerevisiae/metabolismo , ADN de Hongos/genética , Genes Fúngicos , Prueba de Complementación Genética , Datos de Secuencia Molecular , Mutación , Filogenia , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Homología de Secuencia de Aminoácido , Temperatura
11.
J Bioenerg Biomembr ; 35(1): 57-65, 2003 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-12848342

RESUMEN

The putative functions of NDP (nucleoside diaphosphate) kinases from various organisms focusing to fungi and plants are described. The biochemical reactions catalyzed by NDP kinase are as follows. (i) Phosphotransferring activity from mainly ATP to cognate NDPs generating nucleoside triphosphates (NTPs). (ii) Autophosphorylation activity from ATP and GTP. (iii) Protein kinase (phosphotransferring) activity phosphorylating such as myelin basic protein. NDP kinase could function to provide NTPs as a housekeeping enzyme. However, recent works proved possible functions of the NDP kinases in the processes of signal transduction in various organisms, as described below. 1) By use of the extracts of the mycelia of a filamentous fungus Neurospora crassa blue-light irradiation could increase the phosphorylation of a 15-kDa protein, which was purified and identified to be NDP kinase (NDK-1). By use of the etiolated seedlings of Pisum sativum cv Alaska and Oryza sativa red-light irradiation of intact plants increased the phosphorylation of NDP kinase. However, successive irradiation by red-far-red reversed the reaction, indicating that phytochrome-mediated light signals are transduced to the phosphorylation of NDP kinase. 2) NDP kinase localizing in mitochondria is encoded by nuclear genome and different from those localized in cytoplasm. NDP kinase in mitochondria formed a complex with succinyl CoA synthetase. 3) In Spinicia oleraceae two different NDP kinases were detected in the chloroplast, and in Pisum sativum two forms of NDP kinase originated from single species of mRNA could be detected in the choloroplast. However, the function of NDP kinases in the choloroplast is not yet known. 4) In Neurospora crassa a Pro72His mutation in NDP kinase (ndk-1Pro72His) deficient in the autophosphorylation and protein kinase activity resulted in lacking the light-induced polarity of perithecia. In wild-type directional light irradiation parallel to the solid medium resulted in the formation of the perithecial beak at the top of perithecia, which was designated as "light-induced polarity of perithecia." In wild-type in darkness the beak was formed at random places on perithecia, and in ndkPro72His mutant the perithecial beak was formed at random places even under directional light illumination. The introduction of genomic DNA and cDNA for ndk-1 demonstrated that the wild-type DNAs suppressed the mutant phenotype. With all these results except for the demonstration in Neurospora, most of the phenomena are elusive and should be solved in the molecular levels concerning with NDP kinases.


Asunto(s)
Hongos/química , Hongos/metabolismo , Regulación Enzimológica de la Expresión Génica/fisiología , Nucleósido-Difosfato Quinasa/química , Nucleósido-Difosfato Quinasa/metabolismo , Plantas/química , Plantas/enzimología , Transducción de Señal/fisiología , Secuencia de Aminoácidos , Hongos/genética , Datos de Secuencia Molecular , Peso Molecular , Nucleósido-Difosfato Quinasa/clasificación , Nucleósido-Difosfato Quinasa/genética , Plantas/genética , Subunidades de Proteína , Análisis de Secuencia de Proteína , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Relación Estructura-Actividad
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