共查询到20条相似文献，搜索用时 421 毫秒
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EST技术在植物基因克隆和基因表达谱研究中的应用 总被引：2，自引：0，他引：2
表达序列标签是cDNA的部分序列，是通过对cDNA库进行大规模上次性测序而获得．对于植物研究而言，该技术已成为一种高效、经济的克隆重要植物基因的工具．而且，通过分析来自特定组织的EST库可以定量地估计该组织中各类基因的表达丰度．这种组织基因表达谱可用于阐明植物的代谢调控网络或植物对生物、非生物胁迫反应的信号转导途径．章以几个典型的实例阐释如何利用EST技术来克隆重要的植物经济性状基因及以此技术进行表达谱研究． 相似文献
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通过实验手段向细胞内导入长的双链RNA或者转基因可以产生一些短片段的双链RNA,这些短片段的双链RNA可以通过促使特定基因的mRNA降解来高效、特异地阻断体内特定基因的表达,使细胞出现特定基因缺失的表型,称为RNA干扰(RNA interference,RNAi)。SiRNA(small interference RNA)就是这种短片段双链RNA分子,能够以序列同源互补的mRNA为靶目标,降解特定的mRNA。基本上所有的生物体内也都存在一种内源的小分子RNA,为单链RNA,由基因组转录生成,但是不编码蛋白质,它们的功能在于调节mRNA的翻译,称为miRNA,是由具有发夹结构的前体剪切产生的。RNAi的发现具有划时代的意义,它不仅揭示了细胞内基因沉默的机制,而且有望成为后基因组时代基因功能分析的有力工具,极大地促进了人类揭示生命奥秘的进程。 相似文献
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以cDNA微阵列检测313个已知基因在萌发期水稻幼苗中的表达谱 总被引：1，自引：0，他引：1
使用含512个已知水稻基因3′表达序列标签的cDNA微阵列检测了萌发期水稻幼苗的基因表达谱，313个基因产生了可靠的杂交信号．其中，天冬氨酸氨基转移醇基因和4个具有核糖体功能的基因表达丰度非常高，表明萌发期幼苗中的氨基酸和蛋白质的合成代谢很活跃．β—l，3一葡聚糖酶基因是一种典型的病程相关基因，该基因的高水平表达，表明幼苗中存在着一种高度发育的抗病机制．实验也发现编码一种重要的抑制细胞凋亡的基因-Bax inhibitor-1，在幼苗中的表达丰度很高；该结果可解释为什么正常的幼苗中很少发生细胞程序性死亡现象．实验所测定的大量基因的表达丰度有助于从基因组转录水平理解萌发幼苗的生理特点． 相似文献
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Wen-biao CHEN Jian-rong HUANG Xiang-qi YU Xiao-cong LIN Yong DAI 《Journal of Zhejiang University. Science. B》2015,16(3):235-250,166
目的:寻找来源于Alport综合征患者与正常对照者的多能干细胞差异性表达的microR NA,并对差异性表达的microR NA靶基因进行预测。创新点:本研究不同于一般的试验标本,试验标本是来源于尿肾脏管细胞诱导而成的多能干细胞。基于Alport综合征是遗传疾病,我们对一遗传家系进行了系统的分析。寻找特异性的差异性表达microR NA及其靶基因,从基因水平对Alport综合征进行研究。方法:在前期工作中,成功地从实验者与对照者的尿肾脏管细胞诱导成多能干细胞。运用高通量测序技术分析并发现实验者与对照者之间差异性表达的microR NA。对差异性表达的microR NA靶基因进行预测,并进行靶基因聚集分析,研究靶基因主要参与的生物学过程。同时进行靶基因信号传导通路的分析,研究靶基因主要参与的细胞信号传导通路。结论:在实验组与对照组之间,发现了30个具有显著差异性表达的microR NAs,包括19个上调表达与11个下调表达。差异性表达的microR NA的靶基因主要聚集在细胞膜和细胞代谢过程;靶基因主要参与嘌呤代谢通路与丝裂原活化蛋白激酶(MAPK)通路。 相似文献
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孙亮先 《泉州师范学院学报》2004,22(2):94-99
对GenBank中9215条来源于水稻(Oryza sativa L.ssp．Indica)胚乳cDNA库的3’EST进行了分析，获得20个淀粉合成相关基因的表达丰度信息，研究发现淀粉合成的5个关键酶的编码基因，ADPG焦磷酸化酶基因、ADP—葡萄糖淀粉合成酶、淀粉分支酶、淀粉去分支酶、蜡质基因的表达丰度极高，表明该时期水稻胚乳内淀粉合成反应非常强烈，研究发现在淀粉合成途径中存在功能相关的基因协同表达的现象，章结合所获得的基因表达信息对淀粉合成的分子机理进行了探讨。 相似文献
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To compare mid-infrared(MIR)and near-infrared(NIR)spectroscopies for the determination of the fat and protein contents in milk,the same sample sets with varying concentrations of fat and protein were measured in the MIR range of 3 200-700 cm-1 and NIR range of 9 000-4 000 cm-1.The spectral features in the two regions were analyzed.The MIR spectra of milk were characteristic due to the MIR inherent molecular specificity,whereas the NIR spectra were relatively characterless due to the NIR low selectivity.Partial least squares(PLS)regression models for fat and protein were developed by using both MIR and NIR spectra.MIR data with no pretreatment gave better results than NIR data.The square correlation coefficient(R2)and the root mean square error of prediction(RMSEP)were 0.98 and 0.10 g/dL for fat and 0.97 and 0.11 g/dL for protein.With NIR techniques,satisfactory results were not obtained with raw data.However,NIR data after pretreatment gave similarly good results to the ones using MIR method.This paper indicates that either of the MIR and NIR spectral methods is reliable for the determination of the fat and protein contents. 相似文献
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Xiao-liang Li Yue Kang Xiao-yan Zhang Bing-lin Zhu Wei-huan Fang 《Journal of Zhejiang University. Science. B》2012,13(6):465-477
The heat shock cognate protein 70 (Hsc70) is a member of a 70-kDa heat shock protein (HSP70) family that functions as molecular chaperones. In this study, a novel Hsc70 gene from Chinese soft-shelled turtle (Pelodiscus sinensis) (tHsc70) was identified. The tHsc70 full-length complementary DNA (cDNA) is 2 272 bp long with a 1 941-bp open reading frame (ORF) encoding 646 amino acids. Three characteristic signature regions of the HSP70 family, two major domains of an adenosine triphosphate (ATP)/guanosine triphosphate (GTP) binding domain (ABD), and a substrate-binding domain (SBD) were present in the predicted tHsc70 amino acid sequence. The tHsc70 gene was expressed in Escherichia coli BL21 and the expression product reacted with the anti-Hsc70 mouse monoclonal antibody by Western blotting. Homology analysis revealed that tHsc70 shared identity from 53.9% to 87.7% at the nucleotide level, and 49.1% to 99.5% at the amino acid level with the known Hsc70s. Phylogenetic analysis showed that tHsc70 was clustered together with the Hsc70 gene of another reptile species (Alligator mississippiensis). The tHsc70 was expressed in the liver, lung, heart, and skeletal muscle. The expression patterns of tHsc70 messenger RNA (mRNA) differed among different tissues under different durations of heat stress at 40 °C. Adaptation at 25 °C for 1 h after heat stress was also different among tissues and length of heat stress. Irrespective of different profiles of expression under heat stress, tHsc70 may play roles in protecting turtles from thermal stress. 相似文献
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Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes 总被引：2，自引：0，他引：2
INTRODUCTION Aluminum (Al) toxicity is one of the mostimportant yield-limiting factors for crop grown onacid upland and lowland acid sulphate soils (IRRI,1978). Al toxicity results in a reduced and damagedroot system, which in turn causes the affectedplants to be susceptible to drought stress and min-eral nutrient deficiencies (Foy, 1988). The physio-logical and biochemical mechanisms of the toxiceffect of Al on root elongation had been extensivelyinvestigated (Matsumoto, 2000). T… 相似文献
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核糖体是细胞生长所需的蛋白质合成的动力工厂,每一个核糖体的大小为4兆而顿,有18S、5．8S、28S和5S四种RNA及80S等蛋白质组成,细胞中约有50％的RNA是核糖体RNA,这些RNA直接或间接地参与形成数百万的核糖体,因此,核糖体RNA基因的转录调控机制一直是细胞生长和细胞周期调控研究的热点,细胞通过进化已经形成一套完整的配合RNA聚合酶共同完成的核糖体RNA转录调控机制。本文从核糖体RNA基因结构出发,就染色质重塑、组蛋白乙酰化及细胞周期三个方面探讨核糖体RNA转录调控机制。 相似文献
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INTRODUCTION Gene duplication provides a main resource of new genes in genomes (Ohno, 1970; Brown, 1999). Sequences of two paralogous genes from a duplication event will become different from each other along with evolutionary processes. And the difference in sequences caused by substitution, deletion, insertion of nucleotide acid will cause maximal sequence lengths of exact match (MALE) between paralogous members from a gene family to become shorter during evolution. As for example, o… 相似文献
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Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL. 相似文献
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Appressorium formation is an important event in establishing a successful interaction between the rice blast fungus, Magnaporthe oryzae, and its host plant, rice. An understanding of molecular events occurring in appressorium differentiation will give new strategies to control rice blast. A quick and reliable method to extract total RNA from appressorium is essential for studying gene expression during appressorium formation and its mechanism. We found that duplicate film is an efficient substratum for appressorium formation, even when inoculated with high density conidia. When inoculated with conidia at 1×106ml-1, the percentages of conidium germination and appressorium formation were (97.98±0.67)% and (97.88±0.45)%, respectively. We applied Trizol before appressorium collection for total RNA isolation, and as much as 113.6 pg total RNA was isolated from the mature appressoria at 24 h after inoculation. Functional analysis of two genes, MNH6 and MgATG1, isolated from the cDNA subtractive library, revealed that the quantity of RNA was good enough to construct a cDNA (complementary DNA) library or a cDNA subtractive library. This method may be also applicable for the appressorium RNA isolation of other pathogenic fungi in which conidia differentiate into appressoria in the early stages of host infection. 相似文献
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在SL反式剪接过程中,生物利用SL RNA分子上的SD位点和pre-mRNA分子上的SA位点,在剪接体的作用下,将SL作为小型外显子加到pre-mRNA上形成成熟的mRNA。SL反式剪接这一古老的生物学过程在那些进化缓慢的分子中被完整地保留了下来。不同生物间的SL在大小和组成上有时差别很大;个别生物中还存在着组成完全不同的两种SL,它们在pre-mRNA的加工过程中有着不同的作用。几乎所有的SL RNA在结构上有着惊人的相似之处,包括5’末端的TMG帽子结构、保守的SD位点、Sm位点、SL RNA二级结构等。由于pre-mRNA在转录过程中丢失了SA位点或获得了SD位点,大多数脊椎动物在进化过程中丢失了SL反式剪接方式,而这种丢失可能是导致脊椎动物C值增高的原因之一。 相似文献
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Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the
preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator
(GPT) was isolated from a cDNA library of immature seeds of rice and named asOsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of
70 amino acid residues. TheOsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression ofOsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported viaGPT can be used for starch biosynthesis in rice nongreen plastids.
Project supported by National Natural Scienc Foundation of China (No.39830250) and Natural Science Foundation of Zhejiang
Province (No.2A0106), China. The nucleotide sequence data will appear in the GenBank under accession number AF375053. 相似文献