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Functional interaction of phytochrome B and cryptochrome 2 总被引:38,自引:0,他引:38
Light is a crucial environmental signal that controls many photomorphogenic and circadian responses in plants. Perception and transduction of light is achieved by at least two principal groups of photoreceptors, phytochromes and cryptochromes. Phytochromes are red/far-red light-absorbing receptors encoded by a gene family of five members (phyA to phyE) in Arabidopsis. Cryptochrome 1 (cry1), cryptochrome 2 (cry2) and phototropin are the blue/ultraviolet-A light receptors that have been characterized in Arabidopsis. Previous studies showed that modulation of many physiological responses in plants is achieved by genetic interactions between different photoreceptors; however, little is known about the nature of these interactions and their roles in the signal transduction pathway. Here we show the genetic interaction that occurs between the Arabidopsis photoreceptors phyB and cry2 in the control of flowering time, hypocotyl elongation and circadian period by the clock. PhyB interacts directly with cry2 as observed in co-immunoprecipitation experiments with transgenic Arabidopsis plants overexpressing cry2. Using fluorescent resonance energy transfer microscopy, we show that phyB and cry2 interact in nuclear speckles that are formed in a light-dependent fashion. 相似文献
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Regulation of Ca2+-dependent K+-channel activity in tracheal myocytes by phosphorylation 总被引:30,自引:0,他引:30
Isoprenaline is a beta-adrenergic agonist of clinical importance as a remedy for asthma. In airway smooth muscle its relaxant action is accompanied by hyperpolarization of the membrane and elevation of the level of intracellular cyclic AMP. Hyperpolarization and relaxation are also induced by drugs such as forskolin, theophylline and dibutyryl cAMP, indicating that cAMP-dependent phosphorylation is involved in producing the electrical response. Cyclic AMP-dependent protein kinase (protein kinase A) has been reported to activate Ca2+-dependent K+ channels in cultured aortic smooth muscle cells and snail neurons. The membrane of tracheal smooth-muscle cells is characterized by a dense distribution of Ca2+-dependent K+-channels. We have now examined the effect of isoprenaline and protein kinase A on Ca2+-dependent K+-channels in isolated smooth muscle cells of rabbit trachea, using the patch-clamp technique. Our results show that the open-state probability of Ca2+-dependent K+-channel of tracheal myocytes is reversibly increased by either extracellular application of isoprenaline or intracellar application of protein kinase A. We also show that this effect is significantly enhanced and prolonged in the presence of a potent protein phosphatase inhibitor, okadaic acid. 相似文献
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《河南科技大学学报(自然科学版)》2014,(5)
对Ca2+和MS营养处理转VHA-c-GUS烟草叶片的GUS表达活性进行分析。研究结果表明:VHA-c2和VHA-c3可被Ca2+促进表达,而VHA-c5的表达则被Ca2+抑制。同时,MS营养成分可显著促进VHA-c2、VHA-c3和VHA-c5基因的表达。这说明VHA-c基因可被Ca2+和MS等营养成分调控表达。 相似文献
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Ethylene gas is used as a hormone by plants, in which it acts as a critical growth regulator. Its synthesis is also rapidly evoked in response to a variety of biotic and abiotic stresses. The Arabidopsis ethylene-overproducer mutants eto2 and eto3 have previously been identified as having mutations in two genes, ACS5 and ACS9, respectively; these encode isozymes of 1-aminocyclopropane-1-carboxylic acid synthase (ACS), which catalyse the rate-limiting step in ethylene biosynthesis. Here we report that another ethylene-overproducer mutation, eto1, is in a gene that negatively regulates ACS activity and ethylene production. The ETO1 protein directly interacts with and inhibits the enzyme activity of full-length ACS5 but not of a truncated form of the enzyme, resulting in a marked accumulation of ACS5 protein and ethylene. Overexpression of ETO1 inhibited induction of ethylene production by the plant growth regulator cytokinin, and promoted ACS5 degradation by a proteasome-dependent pathway. ETO1 also interacts with CUL3, a constituent of ubiquitin ligase complexes in which we propose that ETO1 serves as a substrate-specific adaptor protein. ETO1 thus has a dual mechanism, inhibiting ACS enzyme activity and targeting it for protein degradation. This permits rapid modulation of the concentration of ethylene. 相似文献
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The cryptochrome/photolyase (CRY/PL) family of photoreceptors mediates adaptive responses to ultraviolet and blue light exposure in all kingdoms of life. Whereas PLs function predominantly in DNA repair of cyclobutane pyrimidine dimers (CPDs) and 6-4 photolesions caused by ultraviolet radiation, CRYs transduce signals important for growth, development, magnetosensitivity and circadian clocks. Despite these diverse functions, PLs/CRYs preserve a common structural fold, a dependence on flavin adenine dinucleotide (FAD) and an internal photoactivation mechanism. However, members of the CRY/PL family differ in the substrates recognized (protein or DNA), photochemical reactions catalysed and involvement of an antenna cofactor. It is largely unknown how the animal CRYs that regulate circadian rhythms act on their substrates. CRYs contain a variable carboxy-terminal tail that appends the conserved PL homology domain (PHD) and is important for function. Here, we report a 2.3-? resolution crystal structure of Drosophila CRY with an intact C terminus. The C-terminal helix docks in the analogous groove that binds DNA substrates in PLs. Conserved Trp?536 juts into the CRY catalytic centre to mimic PL recognition of DNA photolesions. The FAD anionic semiquinone found in the crystals assumes a conformation to facilitate restructuring of the tail helix. These results help reconcile the diverse functions of the CRY/PL family by demonstrating how conserved protein architecture and photochemistry can be elaborated into a range of light-driven functions. 相似文献
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Fischle W Tseng BS Dormann HL Ueberheide BM Garcia BA Shabanowitz J Hunt DF Funabiki H Allis CD 《Nature》2005,438(7071):1116-1122
Tri-methylation of histone H3 lysine 9 is important for recruiting heterochromatin protein 1 (HP1) to discrete regions of the genome, thereby regulating gene expression, chromatin packaging and heterochromatin formation. Here we show that HP1alpha, -beta, and -gamma are released from chromatin during the M phase of the cell cycle, even though tri-methylation levels of histone H3 lysine 9 remain unchanged. However, the additional, transient modification of histone H3 by phosphorylation of serine 10 next to the more stable methyl-lysine 9 mark is sufficient to eject HP1 proteins from their binding sites. Inhibition or depletion of the mitotic kinase Aurora B, which phosphorylates serine 10 on histone H3, causes retention of HP1 proteins on mitotic chromosomes, suggesting that H3 serine 10 phosphorylation is necessary for the dissociation of HP1 from chromatin in M phase. These findings establish a regulatory mechanism of protein-protein interactions, through a combinatorial readout of two adjacent post-translational modifications: a stable methylation and a dynamic phosphorylation mark. 相似文献
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ZHANGXiao SHIMAZAKIKen-ichiro 《科学通报(英文版)》2005,50(11):1166-1168
Phototropins, following the discovery of phytochromes and cryptochromes, are the most recently characterized blue-light (BL) receptors in plants. The Nterminal regions of the proteins contain two light oxygen and voltage (LOV)--LOV1 and LOV2, which belong to PAS domain involved in protein-protein interaction and ligand binding, 相似文献
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拟南芥花药和花粉发育的分子调控机制 总被引:2,自引:0,他引:2
开花植物的花药和花粉发育是一个极其复杂的过程,包含了一系列生物学事件,众多基因参与其中,这些基因控制着花药细胞分裂和分化、小孢子母细胞减数分裂、花粉壁形成、花药开裂释放花粉粒等各个关键步骤,从而调控花药发育的正常进行。本文综述了近年来以拟南芥为主要研究对象进行的有关花药发育分子机制的研究进展,着重介绍小孢子发生起始、成熟花粉粒形成以及花药开裂释放花粉粒等过程的基因调控。 相似文献
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Regulation of distinct AMPA receptor phosphorylation sites during bidirectional synaptic plasticity 总被引:44,自引:0,他引:44
Bidirectional changes in the efficacy of neuronal synaptic transmission, such as hippocampal long-term potentiation (LTP) and long-term depression (LTD), are thought to be mechanisms for information storage in the brain. LTP and LTD may be mediated by the modulation of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazloe proprionic acid) receptor phosphorylation. Here we show that LTP and LTD reversibly modify the phosphorylation of the AMPA receptor GluR1 subunit. However, contrary to the hypothesis that LTP and LTD are the functional inverse of each other, we find that they are associated with phosphorylation and dephosphorylation, respectively, of distinct GluR1 phosphorylation sites. Moreover, the site modulated depends on the stimulation history of the synapse. LTD induction in naive synapses dephosphorylates the major cyclic-AMP-dependent protein kinase (PKA) site, whereas in potentiated synapses the major calcium/calmodulin-dependent protein kinase II (CaMKII) site is dephosphorylated. Conversely, LTP induction in naive synapses and depressed synapses increases phosphorylation of the CaMKII site and the PKA site, respectively. LTP is differentially sensitive to CaMKII and PKA inhibitors depending on the history of the synapse. These results indicate that AMPA receptor phosphorylation is critical for synaptic plasticity, and that identical stimulation conditions recruit different signal-transduction pathways depending on synaptic history. 相似文献
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结合EDTA与Ca2+络合反应和Ca2+与F-沉淀反应,通过调节体系pH值,可实现对EDTA包覆CaF2纳米晶生长的调控。当pH大于7时,不能形成CaF2纳米晶,在pH为6~3时有CaF2纳米晶出现,且随着pH的降低,CaF2纳米晶的产量增加、粒径增大。但当pH降到2时EDTA会大量析出,对CaF2纳米晶的生长不起作用。 相似文献
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利用RT-PCR技术检测VHA-c基因在拟南芥中的表达,结果表明VHA-c3基因在拟南芥的果荚、花、叶、茎和根中都有表达,但是,在叶中的表达量远远高于其它的组织.以GUS基因作为报告基因构建了不同长度的VHA-c3基因启动子缺失突变体,利用农杆菌介导的瞬时表达系统检测GUS基因的表达,研究发现在VHA-c3基因起始密码子上游2812-2 234 bp之间的区域內存在着控制VHA-c3基因高表达的转录调控元件. 相似文献
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以酿酒酵母为研究材料,通过体外甲基化、体内免疫共沉淀等一系列实验,研究了酵母组蛋白甲基转移酶Set2片段调控SET结构域催化活性的机制。发现将SRI 结构域敲除后(1─618片段),仅催化产生H3K36的单甲基化,将其WW结构域、CC结构域敲除后(1─475片段),H3K36无法被甲基化。将Set2截取到仅剩SET催化结构域(1─261片段),H3K36又可被一甲基化和部分的二甲基化修饰。研究结果表明SET结构域的催化活性并非由Set2蛋白自身折叠调控。 相似文献
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《科学通报(英文版)》2008,(17)
In Arabidopsis thaliana, STN7 kinase is required for phosphorylation of LHCII and for state transitions. In this paper, a hydrophilic polypeptide, derived from the amino acid sequence of STN7, was conjugated to a carrier protein, bovine serum albumin (BSA), to obtain the polyclonal antibody. Immunogenicity and specificity of the polyclonal antibody were evaluated by agar gel immunodiffusion (AGID) test and Western blot analysis. The results show that besides the phosphorylation of LHCII proteins, also the expression of STN7 was regulated by temperature conditions. In addition, the change tendency of LHCII proteins phosphorylation was not only coherent with expression of STN7 with respect to increasing temperature, but also closely related to state transitions. These results would provide useful information for studying regulatory mechanism of LHCII proteins phosphorylation and expression of STN7. 相似文献
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There is considerable evidence that cyclic AMP can modulate the electrical activity of excitable cells and that protein phosphorylation by the catalytic subunit (CS) of cAMP-dependent protein kinase is a necessary step in these modulatory effects. In analogy to alterations in enzyme activities following phosphorylation, it seems possible that direct phosphorylation of ion-channel proteins may alter their gating properties, giving rise to the observe changes in electrical activity. However, the results obtained so far do not indicate whether it is ion channels themselves that are phosphorylated, or whether phosphorylation is simply an early step in some cascade of events which leads ultimately to modulation of channel activity. The development of single-channel recording techniques has provided a way to investigate this question. Here we describe effects of CS on the activity of individual CA2+-dependent K+ channels from the nervous system of the land snail Helix measured in isolated membrane patches and in artificial phospholipid bilayers. The results demonstrate that cAMP-dependent protein phosphorylation produces long-lasting changes in the activity of individual channels, and indicate that the relevant phosphorylation site is closely associated with the channel. 相似文献
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根据开关磁阻电动机调速系统 ( SRD)的 PWM调压调速理论 ,论述了采用集成电路TL494实现 SRD的 PWM调压调速的原理。实验证明 ,该方案控制方便 ,可靠性高 ,调速范围较宽 ,简单易行 ,特别适用于小功率开关磁阻电动机的调速系统。 相似文献