103 resultados para RNA-POLYMERASE HOLOENZYME
Resumo:
植物激素乙烯作为一种信使分子调节控制果实完熟。ACC合成酶是植物体内乙烯生物合成途径的限速酶,其反义RNA的表达将能有效地抑制乙烯的生物合成而延缓果实完熟,利用反转录PCR技术克隆获得了ACC合成酶多基因家族成员之一LE-ACC2阅读框架约1.7kb的cDNA,经酶切图谱和序列分析鉴定无误后,反向连入植物表达载体pBin437中构建成组成型表达ACC合成酶反义RNA的双元载体。经农杆菌途径转化番茄“丽春”品种,获得了60株抗卡那再生杭株,PCR检测证明有6株为转基因植株,Southern杂交和Northern杂交分析进一步确证了外源基因的插入及其转录活性。反义番茄果实的乙烯释放受到明显抑制,表现出更好的耐储保鲜特性,并且与对照相比,在果实品质上没有明显差别。大田培育Fl和F2代转化番茄植株,反义番茄纯合品系的筛选工作正在进行之中。 同时,本研究利用已经获得的ACC合成酶和PG的cDNA克隆,构建了两个嵌合转化基因载体pPGACC1、pPGACC10,它包括1300bp的ACC合成酶cDNA编码序列,并分别含有反向与正向的250bp的5’端PG基因片断。酶切图谱和序列分析鉴定无误后,以pBin437为植物表达载体构建了双元载体pBPGACC1和pBPGACC10,分别表达PG正义RNA和反义RNA,并均表达ACC合成酶反义RNA。经农杆菌转化番茄子叶,植株的再生培育有待进行。通过对转基因植物的分析,我们期望阐明用单一嵌合基因表达载体通过反义抑制与抑制作用实现对内源两同源基因——PG和ACC合成酶下降调节的可能性,并可望得到具有更好耐储效果且品质优良的番茄品系。
Resumo:
本发明公开了金丝桃素的新用途。本发明发明人的实验证实,金丝桃素对RNA病毒,特别是禽流感病毒,口蹄疫病毒和犬瘟热病毒具有较好的抑制和灭活效果,可以该化合物为活性成分,制备成抗RNA病毒药物。该抗病毒药物可用于临床防治和治疗禽流感、犬瘟热、口蹄疫等由RNA病毒引发的疾病,对禽业、犬业及畜牧养殖业等意义重大。此外,我国草药资源丰富,该药物具有工业化生产的可行性。综上所述,金丝桃素将在医学和生物制药领域,尤其是抗RNA病毒药物的制备领域具有较大的实际意义和广阔的应用前景。
Resumo:
双尾虫是否单系,以及双尾虫与其他六足动物系统关系是多年来动物分类学家争议的一个关键问题。测定了双尾虫的两大类群:康 类和铗 类,以及原尾虫、跳虫和蝗虫等核糖体RNA基因18SrDNA全序列和28SrDNA部分序列(D3-D5区),并选用甲壳动物卤虫为外群,采用最大筒约(MP)法构建分子系统树。结果表明:(i)18SrDNA和28SrDNA数据整合分析含有较强的系统发育信息,支持双尾虫单系性观点;(ii)双尾虫与原尾虫在系统中构成姊姝群,且支持率很高。
Resumo:
Objective: To investigate the association of complement C4 null genes (C4QO, including C4AQO and C4BQO) and C2 gene with systemic lupus erythematosus (SLE) in southwest Han Chinese; 136 patients with SLE and 174 matched controls were genotyped. Methods: C4 null genes were determined by a polymerase chain reaction (PCR) procedure with sequence specific primers (PCR-SSP). The 2 bp insertion in exon 29, which was previously identified in non-Chinese populations and caused defective C4A genes, was directly typed by sequencing the whole exon 29 using exon specific primers. The exon 6 of complement C2 was also sequenced in both the patients and controls. Results: The frequency of homozygous C4AQO allele was 12.5% (17/136) in patients with SLE compared with 1.1% (2/174) in controls (p<0.001, odds ratio (OR)=12.286, 95% confidence interval (95% CI) 2.786 to 54.170). There was no significant difference for homozygous C4BQO allele between patients with SLE and controls (p=0.699). Patients with the C4AQO gene had an increased risk of acquiring renal disorder, serositis, and anti-dsDNA antibodies compared with those without C4AQO (for renal disorder, p=0.018, OR=8.951, 95% Cl 1.132 to 70.804; for serositis, p=0.011, OR 4.891, 95% CI 1.574 to 15.198; for anti-dsDNA, p=0.004, OR 7.630, 95%Cl 1.636 to 35.584). None of the patients or controls had the 2 bp insertion in exon 29 of the C4 gene. The type I C2 deficiency was not detected in the 3 10 samples. Conclusion: It is suggested that deficiency of C4A (not due to a 2 bp insertion in exon 29), but not C4B or C2, may be a risk factor for acquiring SLE in south west Han Chinese; this results in increased risk of renal disorder, serositis, and anti-dsDNA antibodies in patients with SLE. Racial differences seem to be relevant in susceptibility to SLE.
Deep RNA sequencing at single base-pair resolution reveals high complexity of the rice transcriptome
Resumo:
Understanding the dynamics of eukaryotic transcriptome is essential for studying the complexity of transcriptional regulation and its impact on phenotype. However, comprehensive studies of transcriptomes at single base resolution are rare, even for modern organisms, and lacking for rice. Here, we present the first transcriptome atlas for eight organs of cultivated rice. Using high-throughput paired-end RNA-seq, we unambiguously detected transcripts expressing at an extremely low level, as well as a substantial number of novel transcripts, exons, and untranslated regions. An analysis of alternative splicing in the rice transcriptome revealed that alternative cis-splicing occurred in similar to 33% of all rice genes. This is far more than previously reported. In addition, we also identified 234 putative chimeric transcripts that seem to be produced by trans-splicing, indicating that transcript fusion events are more common than expected. In-depth analysis revealed a multitude of fusion transcripts that might be by-products of alternative splicing. Validation and chimeric transcript structural analysis provided evidence that some of these transcripts are likely to be functional in the cell. Taken together, our data provide extensive evidence that transcriptional regulation in rice is vastly more complex than previously believed.
Resumo:
RNAi(RNA interference)为研究未知功能基因提供了新的反向遗传学手段;并能应用于人类的基因治疗。文中就RNAi的研究进展、作用机制及其应用进行了评述,并与基因敲除及反义RNA抑制进行了比较。
Resumo:
dsRNA能阻抑卵母细胞中同源基因的表达,其作用相当于基因敲除。质粒表达的发夹环型dsRNA也可以有效降解basonuclin转录产物,这为研究basonuclin在卵母细胞发育早期的功能提供了新的手段。
Resumo:
In plants and less-advanced animal species, such as C.elegans, introduction of exogenous double-stranded RNA (dsRNA) into cells would trigger degradation of the mRNA with homologous sequence and interfere with the endogenous gene expression. It might represent an ancient anti-virus response which could prevent the mutation in the genome that was caused by virus infection or mobile DNA elements insertion. This phenomenon was named RNA interference, or RNAi. In this study, RNAi was used to investigate the function of basonuclin gene during oogenesis. Microinjection of dsRNA directed towards basonuclin into mouse germinal-vesicle-intact (GV) oocytes brought down the abundance of the cognate mRNA effectively in a time- and concentration-dependent manner. This reduction effect was sequence-specific and showed no negative effect on other non-homologous gene expression in oocytes, which indicated that dsRNA can recognize and cause the degradation of the transcriptional products of endogenous basonuclin gene in a sequence-specific manner. Immunofluorescence results showed that RNAi could reduce the concentration of basonuclin protein to some extent, but the effect was less efficient than the dsRNA targeting towards tPA and cMos which was also expressed in oocytes. This result might be due to the long half life of basonuclin protein in oocytes and the short reaction time which was posed by the limited life span of GV oocytes cultured in vitro. In summary, dsRNA could inhibit the expression of the cognate gene in oocytes at both mRNA and protein levels. The effect was similar to Knock-out technique which was based on homologous recombination. Furthermore, hairpin-style dsRNA targeting basonuclin gene could be produced by transcription from a recombinant plasmid and worked efficiently to deplete the cognate mRNA in oocytes. This finding offered a new way to study the function of basonuclin in the early stage of oogenesis by infection of primordial oocytes with the plasmid expressing hairpin-style basonuclin dsRNA.
Resumo:
Learning and memory are exquisitely sensitive to behavioral stress, but the underlying mechanisms are still poorly understood. Because activity-dependent persistent changes in synaptic strength are believed to mediate memory processes in brain areas such as the hippocampus we have examined the means by which stress affects synaptic plasticity in the CA1 region of the hippocampus of anesthetized rats, Inescapable behavioral stress (placement on an elevated platform for 30 min) switched the direction of plasticity, favoring low frequency stimulation-induced decreases in synaptic transmission (long-term depression, LTD), and opposing the induction of long-term potentiation by high frequency stimulation, We have discovered that glucocorticoid receptor activation mediates these effects of stress on LTD and longterm potentiation in a protein synthesis-dependent manner because they were prevented by the glucocorticoid receptor antagonist RU 38486 and the protein synthesis inhibitor emetine. Consistent with this, the ability of exogenously applied corticosterone in non-stressed rats to mimic the effects of stress on synaptic plasticity was also blocked by these agents, The enablement of low frequency stimulation-induced LTD by both stress and exogenous corticosterone was also blocked by the transcription inhibitor actinomycin D, Thus, naturally occurring synaptic plasticity is liable to be reversed in stressful situations via glucocorticoid receptor activation and mechanisms dependent on the synthesis of new protein and RNA, This indicates that the modulation of hippocampus-mediated learning by acute inescapable stress requires glucocorticoid receptor-dependent initiation of transcription and translation.