Cdx2 expression and its promoter methylation during metaplasia-dysplasia-carcinoma sequence in Barrett's esophagus

AIM:To examine how the expression of caudal type homebox transcription factor 2(Cdx2) is regulated in the development of malignancy in Barrett's esophagus.METHODS:Cdx2,mucin(MUC) series(MUC2,MUC5AC and MUC6),p53 and E-cadherin expression in Barrett's esophagus and adenocarcinoma specimens were examined by immunostaining.Isolated clusters of cells from(1) MUC2 and Cdx2-positive intestinal metaplastic mucosa;(2) MUC5AC and MUC6-positive,and MUC2 and Cdx2-negative high-grade dysplasia(HD),or intramucosal adenocarcinoma(IMC);and(3) MUC5AC,MUC6 and Cdx2-positive poorly-differentiated invasive adenocarcinoma(PDA) were analyzed by methylationspecific polymerase chain reaction using sets of primers for detecting methylation status of the Cdx2 gene.RESULTS:Most of the non-neoplastic Barrett's esophageal mucosa showing intestinal-type metaplasia with or without low-grade dysplasia was positive for E-cadherin,MUC series and Cdx2,but negative for p53.A portion of the low-grade to HD was positive for E-cadherin,MUC5AC,MUC6 and p53,but negative for MUC2 and Cdx2.The definite IMC area was strongly positive for MUC5AC,MUC6 and p53,but negative for MUC2 and Cdx2.Methylation of the Cdx2 promoter was not observed in intestinal metaplasia,while hypermethylation of part of its promoter was observed in hot dipped and IMC.Hypermethylation of a large fraction of the Cdx2 promoter was observed in PDA.CONCLUSION:Cdx2 expression is restored irrespective of the methylation status of its promoter.Apparent positive immunohistochemical results can be a molecular mark for gene silencing memory.

Trichome-Specific Expression of Amorpha-4,11-Diene Synthase, a Key Enzyme of Artemisinin Biosynthesis in <i>Artemisia annua</i>L., as Reported by a Promoter-GUS Fusion

Artemisia annua L. produces small amounts of the sesquiterpenoid artemisinin, which is used for treatment of malaria. A worldwide shortage of the drug has led to intense research to increase the yield of artemisinin in the plant. In order to study the regulation of expression of a key enzyme of artemisinin biosynthesis, the promoter region of the key enzyme amorpha-4,11-diene synthase (ADS) was cloned and fused with the β-glucuronidase (GUS) reporter gene. Transgenic plants of A. annua expressing this fusion were generated and studied. Transgenic plants expressing the GUS gene were used to establish the activity of the cloned promoter by a GUS activity staining procedure. GUS under the control of the ADS promoter showed specific expression in glandular trichomes. The activity of the ADS promoter varies temporally and in old tissues essentially no GUS staining could be observed. The expression pattern of GUS and ADS in aerial parts of the transgenic plant was essentially the same indicating that the cis-elements controlling glandular trichome specific expression are included in the cloned promoter. However, some cis-element(s) that control expression in root and old leaf appears to be missing in the cloned promoter. Furthermore, qPCR was used to compare the activity of the wild-type ADS promoter with that of the cloned ADS promoter. The latter promoter showed a considerably lower activity than the wild-type promoter as judged from the levels of GUS and ADS transcripts, respectively, which may be due to the removal of an enhancing cis-element from the ADS promoter. The ADS gene is specifically expressed in stalk and secretory cells of glandular trichomes of A. annua.

日本落叶松内源GUS基因鉴定及其酶活性分析

[目的]研究日本落叶松内源β-葡糖苷酸酶(GUS)基因及其酶活性,分析GUS作为报告基因的可靠性。[方法]利用pCAMBIA1301载体上的GUS基因序列在日本落叶松参考基因组中进行比对,鉴定并克隆出日本落叶松GUS(LaGUS)基因。在NCBI利用blastp查找其他物种中LaGUS的同源序列并构建进化树。利用已有的转录组数据和实时荧光定量PCR分析LaGUS基因在日本落叶松中的表达模式。利用组织化学的方法,以X-gluc作为GUS酶反应底物,检测日本落叶松体细胞胚胎发生过程中内源GUS的酶活性。[结果]在日本落叶松中鉴定到一个LaGUS基因,CDS长3435 bp,编码1144个氨基酸。25种植物中具有与LaGUS基因相似的序列。LaGUS基因的表达量在活动期高于休眠期,在体胚苗中高于在胚性愈伤组织和体细胞胚胎中。组织化学染色表明,日本落叶松胚性愈伤组织、体细胞胚胎和体胚苗在室温下染色6 d时均观察到蓝色,但体胚苗的染色程度高于胚性愈伤组织和体细胞胚胎。[结论]日本落叶松具有内源GUS活性,在基因工程中利用GUS作为报告基因可能存在一定干扰。

水稻OsTLP12基因启动子GUS表达载体的构建与转化

植物中类甜蛋白TLPs不仅参与宿主抵御真菌入侵的过程,还参与植物对非生物胁迫的防御。本试验采用PCR技术从籼稻特青中克隆了OsTLP12基因上游2000 bp的启动子片段,并分析了其中所含的顺式作用元件。随后,构建了与GUS报告基因融合的表达载体,并通过农杆菌介导的转化方法将融合表达载体导入水稻中,随后进行了转化植株的筛选,并对转基因植株进行了GUS染色分析。本研究得到以下结果:1) 成功克隆了水稻中OsTLP12基因的启动子片段,并将其与含有GUS报告基因的表达载体融合,获得了融合表达载体;2) OsTLP12基因启动子区域含有多个生物和非生物逆境反应相关的顺式元件;3) 成功将融合表达载体转化进入水稻中,并筛选出阳性转基因幼苗;4) 对转基因幼苗进行了GUS染色,以检测OsTLP12基因启动子驱动的GUS表达情况。

Enhanced extracellular production of alpha-lactalbumin from Bacillus subtilis through signal peptide and promoter screening

Alpha-lactalbumin(α-LA)is a major whey protein found in breast milk and plays a crucial role in the growth and development of infants.In this study,Bacillus subtilis RIK1285 harboring AprE signal peptide(SP)was selected as the original strain for the production ofα-LA.It was found thatα-LA was identified in the pellet after ultrasonic disruption and centrifugation instead of in the fermentation supernatant.The original strain most likely only producedα-LA intracellular,but not extracellular.To improve the expression and secretion ofα-LA in RIK1285,a library of 173 homologous SPs from the B.subtilis 168 genome was fused with target LALBA gene in the pBE-S vector and expressed extracellularly in RIK1285.SP YjcN was determined to be the best signal peptide.Bands in supernatant were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and purified by nickel column to calculate the highest yield signal peptide.In addition,different promoters(P_(aprE),P_(43),and P_(glv))were compared and applied.The results indicated that the strain RIK1285-pBE-P_(glv)-YjcN-LALBA had the highestα-LA yield,reaching 122.04μg/mL.This study demonstrates successful expression and secretion of humanα-LA in B.subtilis and establishes a foundation for simulating breast milk for infant formulas and developing bioengineered milk.

Understanding the catalytic performance and deactivation behaviour of second-promoter doped Pt/WO_(χ)/γ-Al_(2)O_(3) catalysts in the glycerol hydrogenolysis for selective and cleaner production of 1,3-propanediol

The selective aqueous-phase glycerol hydrogenolysis is a promising reaction to produce commercially useful 1,3-propanediol(1,3-PDO).The Pt-WOx bifunctional catalyst can catalyse the glycerol hydrogenol-ysis but the catalyst deactivation via sintering,metal leaching,and coking can predominantly occur in the aqueous phase reaction.In this work,the effect of reaction temperature,pressure and second promoter(Cu,Fe,Rh,Mn,Re,Ru,Ir,Sn,B,and P)on catalytic performance and deactivation behaviour of Pt/WOx/-Al2O3 was investigated.When doped with Rh,Mn,Re,Ru,Ir,B,and P,the second promoter boosts catalytic activity by promoting great dispersion of Pt on support and increasing Pt surface area.The increased Bronsted acid sites lead to selective synthesis of 1,3-PDO than 1,2-propanediol(1,2-PDO).The characterization studies of fresh and spent catalysts reveal that the main cause of catalyst deactivation is the Pt sintering,as interpreted based on XRD,CO chemisorption,and TEM analyses.The Pt sintering is affected depending on the second promoter that can either or reduce the interaction between Pt,WO_(χ)/γ and Al_(2)O_(3).As an electron acceptor of Pt in Pt/WO_(χ)/γ-Al_(2)O_(3),Re and Mn as second promoters resulted in increased Pt^(2+) on the catalytic surface,which strengthens the contact between Pt andγ-Al_(2)O_(3) and WO_(χ),resulting in a decrease in Pt sintering.The metal leaching and coking are not affected by the presence of second promoter.The catalyst modified with a second promoter possesses improved catalytic activity and 1,3-PDO production,however the stability continues to remain a challenge.The present work unrav-elled the determining parameters of catalytic activity and deactivation,thus providing a promising pro-tocol toward effective catalysts for glycerol hydrogenolysis.

Revisiting the mitigation of coke formation:Synergism between support&promoters'role toward robust yield in the CO_(2)reformation of methane

CO_(2)reformation of methane(CRM)and CO_(2)methanation are two interconnected processes with significant implications for greenhouse gas reduction and sustainable energy production for industrial purposes.While Nibased catalysis suffers from poor stability due to coke formation or sintering,we report a super stable remedy.The active sites of mesoporous MgO were loaded using wet impregnation.The incorporation of Ni and promoters altered the physical features of the catalysts.Sm–Ni/MgO showed the smallest crystallite size,specific surface area,and pore volume.The Sm–Ni/MgO catalyst was selected as the most suitable candidate for CRM,with 82%CH4 and H2/CO ratio of approximately 100%and also for CO_(2)methanation with the conversion of carbon dioxide(82%)and the selectivity toward methane reaches 100%at temperatures above 300ᵒC.Furthermore,the Sm–Ni/MgO catalyst was stable for 900 min of continuous reaction,without significant carbon deposition.This stability was largely due to the high oxygen mobility on the catalyst surface in the presence of Sm.Overall,we demonstrated the efficacy of using promoted Ni catalysts supported by mesoporous magnesia for the improved reformation of greenhouse gases.

Molecular cloning,characterization and promoter analysis of LbgCWIN1 and its expression profiles in response to exogenous sucrose during in vitro bulblet initiation in lily

Lily(Lilium spp.) is an important ornamental flower, which is mainly propagated by bulbs. Cell wall invertases(CWINs), which catalyze the irreversibly conversion of sucrose into glucose and fructose in the extracellular space, are key enzymes participating in sucrose allocation in higher plants. Previous studies have shown that CWINs play an essential role in bulblet initiation process in bulbous crops, but the underlying molecular mechanism remains unclear. Here, a CWIN gene of Lilium brownii var. giganteum(Lbg) was identified and amplified from genomic DNA. Quantitative RT-PCR assays revealed that the expression level of LbgCWIN1 was highly upregulated exactly when the endogenous starch degraded in non-sucrose medium during in vitro bulblet initiation in Lbg. Phylogenetic relationship, motif, and domain analysis of LbgCWIN1 protein and CWINs in other plant species showed that all sequences of these CWIN proteins were highly conserved. The promoter sequence of LbgCWIN1 possessed a number of alpha-amylase-, phytohormone-, light-and stress-responsive cis-elements. Meanwhile, β-glucuronidase(GUS) assay showed that the 459 bp upstream fragment from the translational start site displayed maximal promoter activity. These results revealed that LbgCWIN1 might function in the process of in vitro bulblet initiation and be in the response to degradation of endogenous starch.

Cloning of BjNAC102 Promoter and Construction of Expression Vector in Brassica juncea

Transcription factor NAC102 plays an important role in the abiotic stress responses of plants.In this study,the promoter sequence of 3000 bp located in the upstream of the BjNAC102 gene was cloned from Brassica juncea‘Sichuan Yellow Seed’by using the homologous cloning method.The expression vector of the GUS gene driven by the BjNAC102 promoter was constructed by seamless cloning technology.The results showed that the sequence of the promoter of the BjNAC102 gene contained many cis-acting elements involved in light responsiveness,gibberellinresponsive element,and auxin-responsive element.It was speculated that BjNAC102 played an important role in the abiotic stress response in Brassica juncea.The expression vector of the promoter of the BjNAC102 gene was constructed,which layed a foundation for further studies of the expression pattern of the BjNAC102 gene in Brassica juncea.

CRISPR–Cas9-mediated promoter editing of FERONIA-Like receptor 13 increases plant growth and disease resistance in rice

Receptor kinases play a pivotal role in detecting environmental signals,and consequently,gene pleiotropy is frequently observed within this family.However,the trade-off in trait expression resulting from gene pleiotropy poses a constraint on the utilization of such genes in agricultural breeding.In this study,we identified the receptor kinase gene FERONIA-Like Receptor 13(FLR13)as a pleiotropic gene influencing plant height,tillering,grain yield,and disease resistance.Using promoter editing,we generated novel alleles(FLR13T5T6-1,FLR13T5T6-2)that confer resistance to rice blast and increase per-plant yield.The knockout of the T5T6 segment alleviates the inhibitory effects of two transcription factors,OsGBP1 and OsWRKY53,on FLR13 expression.In summary,our study presents a promising avenue for enhancing the pivotal attributes of receptor-like kinases through a promoter-editing strategy.

Expression Activity of CLCuV Bidirectional Promoter in Agrobacterium tumefaciens

Cotton leaf curl virus (CLCuV) belongs to the subgroup III of geminiviruses with single strand DNA genome. Study demonstrated that the bidirectional promoter of CLCuV had activity in Agrobacterium tumefaciens (Smith et Townsend) Conn. This is the first report for the activity of the bidirectional promoter of geminivirus in A. tumefaciens. Results showed that the activity of the complementary sense promoter was stronger than that of virion sense promoter, and was detected 2-fold higher than that of CaMV 35S promoter in A. tumefaciens. Moreover, the promoter 5' deletion analysis indicated that the mean GUS activity driven by a 287 nucleotides complementary sense promoter fragment (from-287 to the translation initiation site) is 4 times higher than that driven by the whole complementary sense promoter in A. tumefaciens. This result suggested that there might exist negative regulatory elements in this deleted fragment. The function of other cis-elements included in CLCuV complementary sense promoter was also discussed in this paper.

Rice Repetitive DNA Sequence RRD3:a Plant Promoter and Its Application to RNA Interference

Previously, a moderately repetitive DNA sequence （RRD3） was cloned from rice （Oryza sativa L.） by DNA renaturation kinetics. Sequence analysis revealed several conserved promoter motifs, including four TATA-boxes and a CAAT-box, and promoter activity was shown in Escherichia coli and mammalian expression systems. Here, we inserted the RRD3 fragment into the plant promoter-capture vector, pCAMBIA1391Z, and examined whether the RRD3 fragment has promoter activity in plants. Transgenic tobacco and rice calli both showed β-glucuronidase （GUS） activity, indicating that RRD3 can act as a promoter in both monocot and dicot plants. Based on the promoter characteristic of RRD3, we designed a plant universal binary vector, pCRiRRD3, which is suitable for performing researches on plant RNA interference. This vector has two multiple cloning sites to facilitate sense and antisense cloning of the target sequence, separated by an intron fragment of 200 bp. The efficiency of the vector for gene silencing was assayed by histochemical and quantitative fluorometric GUS assays in transgenic tobacco. These research results suggested that this plant RNAi vector pCRiRRD3 can effectively perform gene silencing researches on both monocot and dicot plants.

Lineage-Specific Genome Architecture Links Enhancers and Non-coding Disease Variants to Target Gene Promoters

Long-range interactions between regulatory elements and gene promoters play key roles in transcriptional regulation.The vast majority of interactions are uncharted,constituting a major missing link in understanding genome control.Here,we use promoter capture Hi-C to identify interacting regions of 31,253 promoters in 17 human primary hematopoietic cell types.We show that promoter interactions are highly cell type specific and enriched for links between active promoters and epigenetically marked enhancers.Promoter interactomes reflect lineage relationships of the hematopoietic tree,consistent with dynamic remodeling of nuclear architecture during differentiation.Interacting regions are enriched in genetic variants linked with altered expression of genes they contact,highlighting their functional role.We exploit this rich resource to connect non-coding disease variants to putative target promoters,prioritizing thousands of disease-candidate genes and implicating disease pathways.Our results demonstrate the power of primary cell promoter interactomes to reveal insights into genomic regulatory mechanisms underlying common diseases.

Expression of a Tobacco Glycosyltransferase Gene Driving Promoter in Transgenic Tobacco

[Objective]The study was to analyze the expression of the deletion fragments from the promoter of a glycosyltransferase gene induced both by MeJA and SA cloned from tobacco W38（sm-Ngt） in transgenic tobacco plants.[Method]Using T1 seedlings of sm-Ngt transgenic tobacco lines containing Gus gene controlled by five 5＇ flank deletion promoter fragments different in length as experimental materials,GUS histochemical staining and fluorometric analysis of T1 seedlings treated with MeJA and SA for 16 h were conducted to analyze the effect of MeJA and SA treatment on the expression of 5＇ flank deletion promoter fragments.[Result]Of five 5＇ flank deletion promoter fragments transgenic plant lines,30 d old T1 seedlings containing 220-0 bp promoter fragment performed worst in GUS staining（showing least staining spots）,those containing-524-0 bp and-468-0 bp promoter fragment both performed best.In the plants not treated with MeJA and SA,activities of GUS driven by-524-0 bp and-468-0 bp deletion promoter fragments were enormously higher than that driven by-1 150-0,-800-0 or-220 0 bp,and which were proved to be not resulted from insert copy number by Southern blot.For GUS expression,promoter fragment-800-0 bp expression was doubly induced by both MeJA and SA,while fragment-1 150-0 was induced by MeJA.[Conclusion]There are activity enhancement elements within-524--220 bp of the sm-Ngt in promoter and activity down regulation elements within-1 150--524 bp region,as well as MeJA and SA doubly inducing activity regulation elements in this promoter.

Cloning of Banana Bunchy Top Virus Chinese Zhangzhou Isolate DNA 4 and the Promoter Activity of Its Non_coding Region

Banana bunchy top virus Chinese Zhangzhou isolate (BBTV-ZZ) DNA 4 was amplified by PCR and cloned. Sequence analysis showed that BBTV-ZZ DNA 4 is 1 039 nucleotides (nts) in length and this virus could be one member of BBTV Asian group. Transcriptional initiation site A, which is at the 269 nucleotide, was preliminarily determined by using 5' RACE method. BBTV-ZZ DNA 4 non-coding region was sub-cloned by PCR and inserted into upstream of gfp : : gus plant expression vector pCAMBIA 1304 to construct recombinant plasmid pTA2. Agrobacterium tumefaciens harboring pTA2 was injected into leaves of the tobacco (Nicotiana tabacum L. cv. Xanthi NC) via Agrobacterium-infiltration procedure. Transient expressions of GUS and GFP were determined in injected leaves 3 - 5 d later. GUS activities of pTA2, pCAMBIA 1304 injected and non-injected tobacco leaves respectively were 1.007 0 pmol MU(.)mug(-1.)min(-1), 2.069 0 pmol MU(.)mug(-1.)min(-1) and 0.021 4 pmol MU(.)mug(-1.)min(-1). Indirect ELISA for GFP in 1 mg total protein from pTA2, pCAMBIA 1304 injected and non-injected leaves showed an A(490 nm) value of 89.577, 100.440 and 3.287, respectively. These results showed that the non-coding region of BBTV-ZZ DNA 4 has a promoter activity not only in the virus replication in monocot, but also in driving the expression of a foreign gene in dicot plants.

Promoter effect on the CO_2-H_2O formation during Fischer-Tropsch synthesis on iron-based catalysts

The effects of Mg,La and Ca promoters on primary and secondary CO2 and H2O formation pathways during Fischer-Tropsch synthesis on precipitated Fe/Cu/SiO2 catalysts are investigated.The chemisorbed oxygen atoms in the primary pathway formed in the CO dissociation steps reacted with co-adsorbed hydrogen or carbon monoxide to produce H2O and CO2,respectively.The secondary pathway was the water-gas shift reaction.The results indicated that the CO2 production led to an increase in both primary and secondary pathways,and H2O production decreased when surface basicity of the catalyst increased in the order Ca 〉 Mg 〉 La.

用基因枪将GUS基因导入褐藻细胞中表达

于1993年11月-1994年2月，用高压氦气式基因枪，将PB1221质粒[装有CaMV35s启动子、GUS（β-葡精苷酸酶）基因以及nos的3’调控区]导入海带和裙带菜组织切块中。48h后，在海带假根细胞和裙带菜中肋部叶片细胞中检测到GUS基因的表达。实验表明，微粒子轰击法是外源基因导入大型褐藻的一个有效途径。CaMV35s启动子能够驱动外源基因在海洋藻类中的表达，可作为藻类基因工程的启动元件。

苜蓿愈伤组织诱导及GUS基因瞬时表达

用电击转化法将质粒pBI12 1(含GUS基因 ,β 葡萄糖苷酸酶基因 )导入苜蓿愈伤组织的小细胞团内 。

转基因水稻中GUS蛋白质的检测及其表达特征

【目的】建立转基因水稻中GUS蛋白质的免疫学检测方法,并了解花椰菜花叶病毒(CaMV)35S启动子驱动的GUS蛋白质在转基因水稻中的表达特征。【方法】以细菌基因组DNA为模板,PCR扩增GUS基因后克隆到表达载体pET30a中,测序验证的重组子转入大肠杆菌表达菌BL21中,IPTG诱导获得重组表达的GUS蛋白质,用HIS-tag beads纯化后作为免疫原免疫小鼠制备GUS蛋白质特异的抗体,通过免疫印迹分析筛选高特异性的单克隆抗体,用Broadford法对重组的GUS蛋白质进行定量,对不同浓度的GUS蛋白质进行免疫印迹分析,绘制检测GUS蛋白质的标准曲线,通过与标准曲线的比较对水稻叶片中GUS蛋白质进行定量分析。提取不同时期、不同部位的水稻总蛋白质,包括苗期的地上部、地下部,分蘖期的茎、茎节、叶鞘、叶枕、叶片上部、叶片中部和叶片下部,孕穗期的茎、穗轴、叶鞘、叶枕、叶片、幼穗(长度分别为1、2、10和20 cm),开花期的茎、穗轴、叶鞘、叶片、穗子,成熟期的茎、叶片、授粉后不同时期的种子(分别为授粉后10、20、30和40 d)、乳熟期的胚、胚乳和颖壳、成熟种子的全种子、胚、胚乳和颖壳以及不同时期的叶片和根部材料等。SDS-PAGE分离后用抗体检测其GUS蛋白质的丰度。【结果】筛选获得了高特异性的抗GUS单克隆抗体(编号为#27),用该抗体检测转基因水稻中及重组的GUS蛋白质均呈现特异条带,没有可见的背景信号,用本研究建立的免疫印迹方法对重组GUS蛋白质的检测下限约为4 ng,可检出转基因水稻单粒大米2.5%样品中(约0.6 mg)的GUS蛋白质。在不同时期的转基因水稻叶片中GUS蛋白质的表达丰度基本稳定,而在水稻根部的GUS丰度随生长急剧减少,5叶期根中的表达量不到3叶期的三分之一,到6叶期检测不到GUS蛋白质。在水稻苗期叶片中,GUS蛋白质约占鲜重的0.02‰。另外,除分蘖期以后的根部之外,GUS蛋白质几乎在所有的水稻组织部位中呈组成型表达,只是不同组织中的表达量略有差异,如在孕穗期和开花期的茎及颖壳中的表达量较低。【结论】建立了具有应用价值的对转基因水稻中GUS蛋白质丰度检测的免疫印记方法。该方法特异性高、样品用量少、不依赖于GUS蛋白质的酶活性、测定结果易于在不同实验室间比较。证明了35S启动子驱动的GUS蛋白质在转基因水稻中基本呈组成型表达。

GUS基因在杜氏盐藻细胞中的瞬间表达

利用电激法将GUS基因转入杜氏盐藻细胞内进行瞬间表达 ,研究了盐藻的生长状态和电激转化条件对转化率的影响 ,并比较了CaMV35S、Ubil、Ubil Ω、CaMV35S U bil和CaMV35S Ubil Ω 5种启动子的转化效率。结果表明 ,培养 5d的盐藻在 6kV的脉冲电压、0 .0 5s的脉冲持续时间和 2 10的脉冲次数下电激可获得较高的转化率 ,为转化最佳条件。 5种启动子中 ,Ubil Ω启动子的转化效率最高 。