Effects of basic fibroblast growth factor on hippocampal and parietal cortical neuronal cAMP-response element-binding protein expression in a rat model of focal cerebral ischemia/reperfusion

BACKGROUND： cAMP-response element binding protein （CREB） is a key modulator of various signaling pathways. CREB activation initiates a series of intracellular signaling pathways that promote neuronal survival. OBJECTIVE： To investigate the regulatory effects of basic fibroblast growth factor （bFGF） on cerebral neuronal CREB expression following ischemia/reperfusion injury. DESIGN, TIME AND SETTING： An immunohistochemical detection experiment was performed at the Department of Anatomy, Shenyang Medical College, between October 2006 and April 2008. MATERIALS： A total of 60 healthy, adult, Wistar rats were randomly divided into three groups： sham-operated （n =12）, ischemia/reperfusion （n = 24）, and bFGF-treated （n = 24）. Rabbit anti-rat CREB （1： 100） and biotin labeled goat anti-rabbit IgG were purchased from the Wuhan Boster Company, China. MetaMorph-evolution MP5.0-BX51 microscopy imaging system was provided by China Medical University, China. METHODS： Rat models of cerebral ischemia/reperfusion injury were developed using the suture method for right middle cerebral artery occlusion. Two-hour ischemia was followed by reperfusion. Rats from the bFGF-treated and ischemia/reperfusion groups were intraperitoneally administered endogenous bFGF （500 IU/mL, 2 000 IU/kg） or an equal amount of physiological saline. Rats from the sham-operated group underwent a similar surgical procedure, without induction of ischemia/reperfusion injury and drug administration. MAIN OUTCOME MEASURES： After 48-hour reperfusion, hippocampal and parietal cortical neuronal CREB expression was detected by immunohistochemistry, and the absorbance of hippocampal CREB-positive products was determined using MetaMorph-evolutionMP5.0-BX51 microscopy imaging system. RESULTS： The sham-operated group exhibited noticeable CREB expression in hippocampal and parietal cortical neurons. In the ischemia/reperfusion group, the CREB expression was discrete and neurons were poorly arranged. The bFGF-treated group exhibited increased CREB expression and better neuronal arrangement compared with the ischemia/reperfusion group. The mean absorbance of CREB-immunoreactive products in the hippocampus and parietal cortex was significantly higher in the ischemia/reperfusion group than in the sham-operated group （P 〈 0.05）, and significantly higher in the bFGF-treated group than in the ischemia/reperfusion group （P 〈 0.05）. CONCLUSION： bFGF significantly upregulates CREB expression in hippocampal and parietal cortical neurons following ischemia/reperfusion injury.

Overexpression of the Watermelon Ethylene Response Factor ClERF069 in Transgenic Tomato Resulted in Delayed Fruit Ripening

Watermelon fruit undergoes distinct development stages with dramatic changes during fruit ripening.To date,the molecular mechanics of watermelon ripening remain unclear.Genetic and transcriptome evidences suggested that the ethylene response factor(ERF)gene ClERF069 may be an important candidate factor affecting watermelon fruit ripening.To dissect the roles of ClERF069 in fruit ripening,structure and phylogenetic analysis were performed using the amplified full-length sequence.Normal-ripening watermelon 97103,non-ripening watermelon PI296341-FR and the RIL population were used to analyze ClERF069 expression dynamics and the correlation with fruit ripening indexs.The results indicated that ClERF069 belongs to ERF family group VI and show high homology(83%identity)to melon ERF069-like protein.ClERF069 expression in watermelon flesh was negatively correlated with fruit lycopene content and sugar content during fruit ripening progress.Further transgenic evidences indicated that overexpression of 35S:ClERF069 in tomato noticeably delayed the ripening process up to 5.2 days.Lycopene,β-carotenoid accumulation patterns were altered and ethylene production patterns in transgenic fruits was significantly delayed during fruit ripening.Taken together,watermelon ethylene response factor ClERF069 was concluded to be a negative regulator of fruit ripening.

Mechanisms of extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway in depressive disorder

The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway plays an important role in the mechanism of action of antidepressant drugs and has dominated recent studies on the pathogenesis of depression. In the present review we summarize the known roles of extracellular signal-regulated kinase, cAMP response element-binding protein and brain-derived neurotrophic factor in the pathogenesis of depression and in the mechanism of action of antidepressant medicines. The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor pathway has potential to be used as a biological index to help diagnose depression, and as such it is considered as an important new target in the treatment of depression.

Insulin-like growth factor-binding protein-3 inhibits IGF-1-induced proliferation of human hepatocellular carcinoma cells

OBJECTIVE Basic fibroblast growth factor(b FGF)and platelet-derived growth factor(PDGF)produced by hepatocellular carcinoma(HCC)cells are responsible for the cell growth.Accumulating evidence shows that insulin-like growth factor-binding protein-3(IGFBP-3)suppresses HCC cell proliferation in both IGF-dependent and independent manners.The present study is to investigate whether treatment with exogenous IGFBP-3 inhibits bF GF and PDGF production and the cell proliferation of HCC cells.METHODS Cell Counting Kit 8 assay were designed to detect HCC cell proliferation,transcription factor early growth response-1(EGR1)involving in IGFBP-3 regulation of b FGF and PDGF were detected by RT-PCR and Western blot assays.Western blot assay was adopted to detect the IGFBP-3 regulating insulin-like growth factor 1 receptor(IGF-1R)signaling pathway.RESULTS The present study demonstrates that IGFBP-3 suppressed IGF-1-induced b FGF and PDGF expression while it does not affect their expression in the absence of IGF-1.To delineate the underlying mechanism,Western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1(EGR1)is involved in IGFBP-3 regulation of b FGF and PDGF.IGFBP-3 inhibition of type 1 insulin-like growth factor receptor(IGF1R),ERK and AKT activation is IGF-1-dependent.Furthermore,transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1,b FGF and PDGF expression.CONCLUSION In conclusion,these findings suggest that IGFBP-3suppresses transcription of EGR1 and its target genes b FGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation.It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation,suggesting that IGFBP-3 could be a target for the treatment of HCC.

The abscisic acid-responsive transcriptional regulatory module CsERF110-CsERF53 orchestrates citrus fruit coloration

Carotenoid biosynthesis is closely associated with abscisic acid(ABA)during the ripening process of non-climacteric fruits,but the regulatory mechanism that links ABA signaling to carotenoid metabolism remains largely unclear.Here,we identified two master regulators of ABA-mediated citrus fruit coloration,CsERF110 and CsERF53,which activate the expression of carotenoid metabolism genes(CsGGPPS,CsPSY,CsPDS,CsCRTISO,CsLCYB2,CsLCYE,CsHYD,CsZEP,and CsNCED2)to facilitate carotenoid accumulation.Further investigations showed that CsERF110 not only activates the expression of CsERF53 by binding to its promoter but also interacts with CsERF53 to form the transcriptional regulatory module CsERF110-CsERF53.We also discovered a positive feedback regulatory loop between the ABA signal and carotenoid metabolism regulated by the transcriptional regulatory module CsERF110-CsERF53.Our results reveal that the CsERF110-CsERF53 module responds to ABA signaling,thereby orchestrating citrus fruit coloration.Considering the importance of carotenoid content for citrus and many other carotenoid-rich crops,the revelation of molecular mechanisms that underlie ABA-mediated carotenoid biosynthesis in plants will facilitate the development of transgenic/gene-editing approaches,further contributing to improving the quality of citrus and other carotenoid-rich crops.

Cotton Major Latex Protein 28 Functions as a Positive Regulator of the Ethylene Responsive Factor 6 in Defense against Verticillium dahliae

In this study, we identified a defense-related major latex protein （MLP） from upland cotton （designated GhMLP28） and investigated its functional mechanism. GhMLP28 transcripts were ubiquitously present in cotton plants, with higher accumulation in the root. Expression of the GhMLP28 gene was induced by Verticillium dahliae inoculation and was responsive to defense signaling molecules, including ethylene, jas- monic acid, and salicylic acid. Knockdown of GhMLP28 expression by virus-induced gene silencing re- sulted in increased susceptibility of cotton plants to V. dahliae infection, while ectopic overexpression of GhMLP28 in tobacco improved the disease tolerance of the transgenic plants. Further analysis revealed that GhMLP28 interacted with cotton ethylene response factor 6 （GhERF6） and facilitated the binding of GhERF6 to GCC-box element. Transient expression assay demonstrated that GhMLP28 enhanced the tran- scription factor activity of GhERF6, which led to the augmented expression of some GCC-box genes. GhMLP28 proteins were located in both the nucleus and cytoplasm and their nuclear distribution was dependent on the presence of GhERF6. Collectively, these results demonstrate that GhMLP28 acts as a positive regulator of GhERF6, and synergetic actions of the two proteins may contribute substantially to protection against V. dahliae infection in cotton plants.

Ethylene Response Factor TERF1 Enhances Glucose Sensitivity in Tobacco through Activating the Expression of Sugar-related Genes

Ethylene response factor （ERF） proteins are important plant-specific transcription factors. Increasing evidence shows that ERF proteins regulate plant pathogen resistance, abiotic stress response and plant development through interaction with different stress responsive pathways. Previously, we revealed that overexpression of TERF1 in tobacco activates a cluster gene expression through interacting with GCC box and dehydration responsive element （DRE）, resulting in enhanced sensitivity to abscisic acid （ABA） and tolerance to drought, and dark green leaves of mature plants, indicating that TERF1 participates in the integration of ethylene and osmotic responses. Here we further report that overexpression of TERF1 confers sugar response in tobacco. Analysis of the novel isolated tomato TERF1 promoter provides information indicating that there are many cis-acting elements, including sugar responsive elements （SURE） and W box, suggesting that TERF1 might be sugar inducible. This prediction is confirmed by results of reverse transcription-polymerase chain reaction amplification, indicating that transcripts of TERF1 are accumulated in tomato seedlings after application of glucose. Further investigation indicates that the expression of TERF1 in tobacco enhances sensitivity to glucose during seed germination, root and seedling development, showing a decrease of the fresh weight and root elongation under glucose treatment. Detailed investigations provide evidence that TERF1 interacts with the sugar responsive cis-acting element SURE and activates the expression of sugar response genes, establishing the transcriptional regulation of TERF1 in sugar response. Therefore, our results deepen our understanding of the glucose response mediated by the ERF protein TERF1 in tobacco.

Effect of Tiantai No.1 (天泰1号) on β-Amyloid-induced Neurotoxicity and NF-κ B and cAMP Responsive Element-binding Protein

Objective： To investigate the effect and molecular mechanism of Tiantai No.1 （天泰1号）, a compound Chinese herbal preparation, for the prevention and reduction of neurotoxicity induced by betaamyloid peptides （Abeta） in vitro and its effects on nuclear factor-κB （NF-κB） and cAMP responsive element-binding protein （CREB） pathways using the gene transfection technique. Methods： B104 neuronal cells were used to examine the effects of Tiantai No.1 on lowering the neurotoxicity induced by Abeta. The cells were pre-treated with Tiantai No.1 at doses of 50, 100,150, or 200μg/mL respectively for 3 days and co-treated with Tiantai No.1 and beta-amyloid peptidel-40 （Aβ 1-40, 10 μmol/L） for 48 h or post-treated with Tiantai No.1 for 48 h after the cells were exposed to beta-amyloid peptides25-35 （Aβ 25-35） for 8 h. In gene transfection assays, cells were treated with Tiantai No.1 at 50 μg/mL and 150μg/mL for 5 days or co-treated with Tiantai No.1 and A 13 1-40 （5 μmo/L） for 3 days after electroporation for the evaluation of NF- κB and CREB expression. Results： Pre-treating and co-treating B104 neuronal cells with Tiantai No.1 lowered the neurotoxicity induced by Abeta, and post-treating with Tiantai No.1 reduced or blocked B104 neuronal apoptotic death induced by Abeta （P〈0.05, P〈0.01）. With a dose-dependent relationship, the same treatments increased the expression of NF-κB or CREB in B104 neuronal cells （P〈0.05, P〈0.01）. Meanwhile, Tiantai No.1 reduced Aβ-40 induced inhibition on NF-κB expression （P〈0.01）. Conclusions： Tiantai No.1 can protect neurons against the neurotoxicity induced by Abeta. The neuroprotective mechanisms may be associated with the activation of NF-κB and cAMP cellular signal pathways.

基于BDNF/CREB信号通路探讨巴戟天对慢性应激抑郁大鼠海马神经元损伤的影响

目的研究巴戟天对慢性应激抑郁大鼠海马神经元损伤及脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)/细胞内环磷腺苷效应元件结合蛋白(cyclic adenosine phosphate response element binding protein,CREB)信号通路的影响。方法从40只SD大鼠随机选取其中10只为正常组,对其余大鼠构建慢性不可预知温和应激模型后,再将其分为3组,即模型组,盐酸氟西汀组(3.17 mg·kg^(-1)),巴戟天组(3.17 g·kg^(-1))。持续灌胃后给药8周,1次/d,并先后在造模前、造模后和给药后开展了行为学实验,以判断大鼠的抑郁情况。通过苏木素-伊红染色(hematoxylin-eosin staining,HE)研究大鼠海马形态学改变,用免疫组织化学法(Immunohistochemistry,IHC)测定大鼠海马BDNF蛋白表达,用HE染色研究大鼠海马组织病理损伤并评分,用实时荧光定量聚合酶链式反应(Real-time PCR,RT-PCR)测定大鼠海马BDNF、TrkB、CREB mRNA相对表达,用蛋白免疫印迹法(western blot,WB)测定大鼠海马BDNF、TrkB、CREB蛋白的相对表达。结果与正常组比较,模型组大鼠活动总路程显著减少(P<0.05),自主游泳时间显著减少(P<0.05),悬尾挣扎时间显著减少(P<0.05)。HE染色结果中表明海马神经元组织受到破坏,病理损伤评分显著下降(P<0.05),免疫组织化学染色中海马BDNF表现显著下降(P<0.05),BDNF、TrkB、CREB mRNA的基因相对表达显著下降(P<0.05);与模型组对比,盐酸氟西汀组和巴戟天组大鼠活动的总里程明显提高(P<0.05),自主游泳时间显著增加(P<0.05),悬尾挣扎时间显著增加(P<0.05),HE染色结果表明海马神经元组织明显复原,病理损伤评分增加(P<0.05),免疫组织化学染色中BDNF表现显著增加(P<0.05),BDNF、TrkB、CREB mRNA的基因相对表达明显增加(P<0.05)。结论经慢性应激刺激后,巴戟天可能通过激活BDNF/TrkB/CREB信号通路对抑郁大鼠海马神经元损伤发挥神经保护作用,改善其抑郁样行为。

基于BDNF/TrkB/CREB通路研究六味地黄丸对丙戊酸钠诱导的孤独症谱系障碍模型仔鼠的作用机制

目的基于脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)/酪氨酸激酶受体B(tyrosine kinase receptor B,TrkB)/cAMP反应元件结合蛋白(cAMP response element binding protein,CREB)通路,探讨六味地黄丸对丙戊酸钠(sodium valproate,VPA)诱导的孤独症谱系障碍(autism spectrum disorder,ASD)仔鼠的作用机制。方法将13只SD孕鼠随机分为两组,其中10只孕鼠在第12.5天时腹腔注射VPA溶液(600 mg·kg^(-1))为VPA组,另外3只孕鼠注射等体积生理盐水为对照组。第21天对两组雄性仔鼠开展行为学检测,筛选出符合ASD疾病模型的仔鼠30只,随机分为模型组(等体积生理盐水),维生素D组(1480 IU·kg^(-1)),六味地黄丸高(3 g·kg^(-1))、中(1.5 g·kg^(-1))、低(0.75 g·kg^(-1))剂量组,每组6只。正常雄性仔鼠6只,设为空白组(等体积生理盐水)。各组仔鼠连续灌胃14 d,1次/d,给药后再次开展行为学检测。尼氏染色观察各组仔鼠海马组织神经元形态学变化,比色法检测各组仔鼠海马组织中谷氨酸(glutamic acid,GLU)、γ-氨基丁酸(gamma-aminobutyric acid,GABA)含量;qRT-PCR检测各组仔鼠海马组织中BDNF、TrkB、CREB mRNA相对表达。结果与对照组比较,VPA组仔鼠体质量、身长、尾长更小(P<0.05)。与空白组比较,模型组社交障碍症状明显(P<0.01),焦虑障碍症状明显(P<0.01),重复刻板行为增多(P<0.05或P<0.01),海马神经元结构损伤,GLU升高(P<0.01)、GABA下降(P<0.01),BDNF、TrkB、CREB mRNA表达降低(P<0.05或P<0.01);与模型组比较,维生素D组及六味地黄丸中、低剂量组仔鼠社交能力增强(P<0.05或P<0.01),焦虑障碍减轻(P<0.05或P<0.01),重复刻板行为减少(P<0.01或P<0.05),海马神经元结构明显复原,GLU下降(P<0.01),BDNF、TrkB、CREB mRNA表达增加(P<0.05或P<0.01),六味地黄丸中、低剂量组GABA上升(P<0.05或P<0.01)。结论六味地黄丸能显著改善VPA诱导的ASD仔鼠行为表现,增强海马组织神经元的再生与修复,其机制可能与平衡GLU、GABA水平,上调仔鼠海马组织中BDNF/TrkB/CREB的表达有关。

小麦ERF转录因子W17互作蛋白的筛选和解析

来自小麦的ERF转录因子W17基因参与胁迫应答,过表达W17可显著提高转基因拟南芥的抗旱性和抗病性。本研究构建了小麦cDNA文库,通过酵母双杂技术筛选W17的互作蛋白,进一步解析ERF蛋白的作用机制。将pGBKT7-W17质粒、pGADT7和小麦文库混合转入酵母细胞AH109,在SD/-Trp/-Leu/-His/-Ade营养缺陷型平板上培养,挑选直径大于2mm的克隆,在SD/Raf/Gal/X-gal平板上划线培养,筛选蓝色克隆。将筛出的克隆测序、BLAST分析,得到4类与W17相互作用的候选蛋白,分别是胁迫相关功能蛋白、翻译后修饰蛋白、1,5-二磷酸核酮糖羧化酶/加氧酶(Rubisco)大亚基/小亚基以及功能未知蛋白。互作验证表明,HSP90和PPR蛋白与W17有相互作用关系。这些候选蛋白参与信号转导或免疫过程,暗示W17在植物的逆境信号转导、下游基因转录调控,甚至在翻译过程都有重要作用。

ERFs转录因子及其在植物胁迫应答中的作用

ERFs(ethylene-responsive factors)是植物特有的一类转录因子,位于乙烯信号转导途径的下游,具有一个高度保守的含58或59个氨基酸的DNA结合域,通过结合相关基因的启动子顺式作用元件调控植物生物和非生物胁迫反应。综述ERF转录因子的结构特征和分类及其在植物抗逆作用中的研究进展。

病原诱导的小麦转录因子TaERF1b基因的分离和表达

【目的】研究一个病原诱导的小麦ERF转录因子基因在对纹枯病菌、赤霉病菌防御反应中的作用。【方法】应用生物信息学、RT-PCR、RACE方法,从赤霉病菌诱导的小麦中,分离ERF转录因子基因的全长cDNA序列;利用半定量RT-PCR方法,分析该基因对小麦纹枯病菌、赤霉病菌及MeJA、ET和SA处理的应答表达情况。【结果】从赤霉病菌诱导的抗赤霉病小麦品种苏麦3号cDNA中,分离出1个编码ERF转录因子基因的全长cDNA序列。该基因暂被命名为TaERF1b,编码由280个氨基酸组成的蛋白质TaERF1b。TaERF1b具有保守的ERF/AP2结构域,但TaERF1b蛋白全长氨基酸序列与已克隆的ERF蛋白同源性较低(<36.5%)。TaERF1b基因表达分析的结果表明,纹枯病菌、赤霉病菌侵染可快速诱导抗病小麦中TaERF1b基因的上调表达,该基因转录表达水平在防卫相关激素乙烯、茉莉酸处理早期显著增强,而且TaERF1b对外源乙烯、茉莉酸处理的响应时期早于对纹枯病菌、赤霉病菌的响应时期。【结论】分离出一个受病原诱导的小麦ERF新基因TaERF1b,其编码蛋白TaERF1b为植物ERF转录因子家族的一个新成员,可能通过茉莉酸、乙烯信号途径介导小麦对纹枯病菌、赤霉病菌的防御反应。

病原诱导的小麦ERF转录因子TaERF1b的原核表达及纯化

为了得到纯化的TaERF1b活性蛋白,将TaERF1 b基因含有AP2/ERF结构域的片段插入原核表达载体pGEX-4T-1的多克隆位点中,构建GST-TaERF1b融合蛋白表达载体,并转化到大肠杆菌BL21(DE3)中。0.1mmol/L IPTG即能诱导融合蛋白表达,37℃诱导4h或30℃诱导8h,融合蛋白均以包涵体的形式表达,16℃诱导12h,融合蛋白不表达。包涵体经溶解及稀释复性后,过GST亲和层析柱,获得纯化的融合蛋白,考马斯亮蓝法测得纯化蛋白的浓度约为0.5μg/μl,凝胶阻滞实验表明包涵体复性成功,所得蛋白具有生物活性。

病原诱导的中间偃麦草ERF转录因子基因的克隆及其表达特性

应用RT-PCR、RACE技术,从病原诱导的中间偃麦草叶片cDNA中,分离出1个编码ERF基因的全长cDNA序列,该基因暂命名为TiERF1 a,编码由292个氨基酸组成的蛋白质,具有ERF转录因子典型的结构,即保守的AP2/ERF DNA结合域、核定位位点和酸性激活区。TiERF1a的氨基酸序列与一个水稻ERF蛋白OsBIERF3具有66%的一致性,与拟南芥AtERF1(O80337)一致性仅39.7%,为植物ERF转录因子家族B3亚群的一个新成员。表达分析结果表明,纹枯病菌、赤霉病菌侵染可诱导TiERF1 a基因的上调表达,与防卫相关的激素乙烯、茉莉酸也可诱导该基因上调表达,且TiERF1 a对外源乙烯、茉莉酸的响应时期早于对纹枯病菌、赤霉病菌响应时期,说明TiERF1 a可能通过乙烯、茉莉酸信号途径参与寄主调控对纹枯病菌、赤霉病菌的防御反应。

香蕉MaERF-1基因的克隆、序列分析及表达载体构建

从香蕉中克隆了1个乙烯响应因子(ERF)Ma ERF-1。序列分析表明,该基因存在1个完整的开放阅读框(ORF)729 bp,编码243个氨基酸。多序列比对和进化树分析表明,Ma ERF-1所编码的蛋白与其他植物中ERF编码的蛋白具有较高的一致性。其中与马来西亚野生香蕉同源性最高达98%,与油棕、菠萝、海枣、葡萄、荷花、烟草的Ma ERF编码的氨基酸序列的同源性分别为65%、60%、59%、54%、53%、51%。Ma ERF-1编码的蛋白质分子量为26 139.03 u,理论等电点p I为7.81,其亲水性氨基酸均匀分布在整个肽链中,多于疏水性氨基酸。通过PCR和酶切反应鉴定成功构建该基因的表达载体。

一个大豆ERF转录因子的克隆与表达分析

利用RT-PCR方法从聚乙二醇(PEG)处理的大豆根部组织中克隆了1个大豆乙烯响应因子(ERF)基因,由于其位于大豆基因组第7染色体上,故命名为GmERF7,基因座为Glyma07g02930。序列分析结果表明:该基因含有1个237 bp长的内含子,开放阅读框(ORF)长585 bp,编码194个氨基酸,蛋白质分子量为2.199×104,理论等电点为7.06;通过氨基酸序列比对发现,该序列与其他物种ERF类蛋白质氨基酸序列有很高的相似性;聚类分析结果表明,GmERF7与苜蓿和蓖麻遗传距离最近,与拟南芥和葡萄遗传距离相对较远;半定量RT-PCR分析结果表明该基因主要在大豆叶和豆荚中表达,而且在外源20%PEG处理不同时间后,该基因的表达在根部组织和叶片组织都受到不同程度的诱导,暗示该基因可能对提高植物耐旱性具有一定作用;利用洋葱表皮细胞的亚细胞定位分析结果表明,该蛋白质位于细胞核内,当去除N端信号肽之后,该蛋白质分布于细胞膜部位,这表明该蛋白质在植物体内通过充当转录因子的作用来调节下游基因的表达;适时定量-PCR(Real-time PCR)分析结果证实,该基因在外源ABA处理后呈现先下调后上调又下降的趋势,表明该基因受ABA的诱导,可能参与了ABA依赖的植物抗逆信号转导途径。

蒺藜状苜蓿中MtERF-6基因的克隆及序列分析

乙烯反应元件结合蛋白属于植物特有的一个转录因子家族,这个家族保守的DNA结合域称为ERF结构域。根据对蒺藜状苜蓿Medicago truncatula测序的数据库进行分析,设计合成引物,通过RT-PCR扩增得到了乙烯反应元件结合蛋白基因(MtERF-6),并测定了其核苷酸全序列。该基因完整的读码框包括654 bp,编码218个氨基酸。用此片段的氨基酸序列通过GenBankBLAST分析表明,该基因属于EREBP(Ethylene responsive element binding proteins)家族,其核苷酸与已报道的ERF4[Gossypium hirsu-tum]、ATERF-9[Arabidopsis thaliana]、NtERF3[Nicotiana tabacum]、NsERF3[Nicotiana sylvestris]、CaEREBP-C1[Capsicum annuum]的相似性分别为45%、47%、41%、40%和42%,是新的基因。MtERF-6的核酸序列在GenBank发表,登录号为DQ344024。

异甘草素对七氟烷致老年大鼠骨折术后认知障碍的影响

目的观察异甘草素对七氟烷致老年大鼠骨折术后认知障碍的改善作用及对细胞外信号调节激酶1/2(extracellular signal-regulated kinase1/2,ERK1/2)/环磷酸腺苷反应单元结合蛋白(cyclic-AMP response element binding protein,CREB)/脑源性神经营养因子(brain derived neurotrophic factor,BDNF)通路的影响。方法将40只骨折大鼠随机分为对照组、模型组、异甘草素组、联合组,每组10只。联合组大鼠灌胃异甘草素(15 mg·kg^(−1)),腹腔注射PD98059(1 mg·kg^(−1));异甘草素组灌胃异甘草素(15 mg·kg^(−1)),腹腔注射等量二甲基亚砜(dimethyl sulfoxide,DMSO);对照组、模型组分别灌胃、腹腔注射等量DMSO。每日1次,持续5 d。用水迷宫实验检测大鼠认知功能;检测血清炎症因子肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白细胞介素-1β(interleukin-1β,IL-1β);Tunel染色法观察海马神经元凋亡情况;免疫印迹法检测海马组织ERK1/2、磷酸化ERK1/2(phospho-ERK1/2,p-ERK1/2)、CREB、p-CREB、BDNF蛋白的表达。结果与模型组[(36.26±3.95)s、(23.91±2.91)s、(5.17±0.68)次、(494.42±45.62)ng·mL^(−1)、(600.98±60.01)ng·mL^(−1)、(34.26%±3.96%)、(0.23±0.03)、(0.14±0.02)、(0.16±0.02)]比较,异甘草素组建模后逃避潜伏期缩短,第三象限停留时间延长,穿越原平台次数增加,血清TNF-α水平、IL-1β水平、海马神经元凋亡率降低,p-ERK1/2/ERK1/2、p-CREB/CREB及BDNF蛋白表达水平升高[(14.87±1.43)s、(45.08±4.54)s、(12.31±1.77)次、(253.41±27.61)ng·mL^(−1)、(229.04±23.55)ng·mL^(−1)、(8.53%±1.06%)、(0.66±0.11)、(0.51±0.05)、(0.60±0.07)],P<0.05;与异甘草素组比较,联合组建模后逃避潜伏期延长,第三象限停留时间缩短,穿越原平台次数减少,血清TNF-α水平、IL-1β水平、海马神经元凋亡率升高,p-ERK1/2/ERK1/2、p-CREB/CREB及BDNF蛋白的表达水平降低[(21.06±2.72)s、(37.17±3.10)s、(7.72±0.96)次、(346.91±44.67)ng·mL^(−1)、(391.38±34.75)ng·mL^(−1)、(16.11%±1.84%)、(0.42±0.05)、(0.29±0.03)、(0.24±0.03)],P<0.05。结论异甘草素可改善术后认知功能障碍、抑制炎症反应、保护海马组织神经元,激活ERK1/2/CREB/BDNF信号通路可能是其作用机制之一。

微RNA-196a-1-3p靶向Ras响应元件结合蛋白调控胆管癌细胞增殖的机制研究

目的探讨转化生长因子β(TGF-β)调控人胆管癌细胞系RBE细胞增殖的关键微RNA(miRNA)及其潜在的机制。方法该研究起止时间为2020年1月至2022年1月。磷酸盐缓冲液(PBS)处理为对照组,TGF-β处理为TGF-β组,TGF-β抗体处理为抗体组。检测三组RBE细胞的增殖水平。miRNA高通量测序检测三组RBE细胞的miRNA调控变化,并进行miRNA模拟物过表达筛选鉴定受TGF-β调控的影响RBE细胞增殖水平的关键miRNA。miRNA数据库(miRDB)在线分析miRNA的潜在底物,并通过小干扰RNA(siRNA)敲低筛选鉴定影响RBE细胞增殖水平的关键底物。结果相比于对照组,TGF-β组RBE细胞的增殖水平上升(1.62±0.07比2.35±0.09,P<0.05),抗体组RBE细胞的增殖水平下降(1.62±0.07比1.11±0.08,P<0.05)。过表达微RNA-196a-1-3p(miR-196a-1-3p)时,RBE细胞的增殖水平下降(P<0.05)。敲低Ras响应元件结合蛋白(RREB1)时,RBE细胞的增殖水平下降(P<0.05)。过表达miR-196a-1-3p后,RBE细胞中RREB1的信使RNA(mRNA)和蛋白水平下降(P<0.05)。敲低miR-196a-1-3p后,RBE细胞中RREB1与SMAD家族蛋白3(SMAD3)的相互作用增加。敲低SMAD3后,RBE细胞的增殖水平下降(P<0.05)。与仅敲低SMAD3相比,敲低SMAD3的同时过表达RREB1的RBE细胞的增殖水平无显著变化,并且同时敲低SMAD3和miR-196a-1-3p的RBE细胞的增殖水平无显著变化。结论TGF-β能够通过miR-196a-1-3p/RREB1/SMAD3轴促进RBE细胞增殖;miR-196a-1-3p和RREB1可作为潜在的治疗胆管癌的靶标,为针对该靶标的新药研发奠定了基础。