植物细胞质雄性不育的育性恢复机理研究进展

植物细胞质雄性不育(Cytoplasmic Male Sterility,CMS)是一种母性遗传现象,表现为不能产生正常功能的花粉.大量研究表明线粒体基因发生分子内或分子间的重组形成嵌合基因,这些嵌合基因的表达产物对线粒体产生毒性,导致了线粒体功能异常,从而导致雄性不育.恢复基因(Restorer of fertility,Rf)对CMS育性的恢复表现为多重效应,即同一物种中存在多个同源的Rf基因,而且对CMS育性恢复的效应和作用方式不同.绝大多数Rf包含不同数目的PPR(Pentatricopeptide Repeat)基序,这些基序形成亲水性的超螺旋结构.Rf对CMS育性恢复的调控是多样的,有的改变CMS相关的线粒体DNA(mtDNA)的结构;有的对线粒体RNA转录本进行加工和编辑;有的影响线粒体蛋白质的丰度.     

B7-2基因工程抗体的制备及体内外抗B淋巴瘤作用研究

 构建B7-2人-鼠嵌合抗体基因表达质粒pIRES/ch3C8,经脂质体法转染真核表达细胞株CHO制备B7-2人-鼠嵌合抗体（命名为ch3C8）。该抗体能够识别人恶性B淋巴瘤细胞株Raji表面的B7-2分子并诱导其凋亡。ch3C8结构中来源于人Ig 的Fc段可介导高效的ADCC及CDC效应。经ch3C8结合的Raji细胞接种于BALB/c裸鼠后的致瘤性消失。该抗体在 B7-2相关肿瘤的生物治疗中具有潜在的应用价值。     

Discovery of mitochondrial chimeric-gene associated with cytoplasmic male sterility of HL-rice

The mitochondrial genome libraries of HL-type sterile line (A) and maintainer line (B) have been constructed. Mitochondrial gene, atp6 , was used to screen libraries, due to the different Southern and Northern blot results between sterile and maintainer line. Sequencing analysis of positive clones proved that there were two copies of atp6 gene in sterile line and only one in maintainer line. One copy of atp6in sterile line was same to that in maintainer line; the other showed different flanking sequence from the 49th nucleotide downstream of the termination codon of atp6 gene. A new chimeric gene, orfH79 , was found in the region. orfH79 had homology to mitochondrial gene coxⅡ and orfH79, and was special to HL-sterile cytoplasm.     

Obtaining transgenic rice resistant to rice fungal blast disease by controlled cell death strategy

The strategy of the two-component system,composed of Barnase and Barstar which encode RNase and a specific inhibitor to the RNase respectively, is adopted to obtain transgenic rice resistant to rice fungal blast disease. In this study, two chimeric promoters, induced by rice blast fungus pathogen (Magnaporthe grisea), are fused with Barnase respectively to construct two plant expression vectors, pWBNBS and pPBNBS together with the Barstar driven by CaMV 35S promoter. The resistance of the transgenic rice lines to rice blast fungus disease and rice blight disease are evaluated. The results show that (1) the expression of Barnase is induced in rice leaves when inoculated with the spores of Magnaporthe grisea; (2) the induced expression level of Barnase surpasses the level of Barstar, which elicits a similar hypersensitive response (HR) in the leaves, and the transgenic plant shows high resistance to the rice fungal blast disease; and (3) transgenic rice plants also show obvious resistance to rice bacterial blight disease. Taken together, these results suggest that the transgenic rice plants harboring this two-component system acquire relatively broad spectrum resistance against pathogens, especially high resistance to rice fungal pathogen.     

Detecting chimeric 5''''l3''''UTRs with cross-chromosomal splicing by bioinformatics

The 5'/3' UTRs of mRNA are crucial in transla-tional regulation, and several serious diseases are believed tobe associated with abnormal splicing of these parts of themRNA sequence. In this work a novel method which usessequence alignment database searching for detecting chi-meric 5'3' UTRs with cross-chromosomal splicing is reported.Eight highly credible instances of cross-chromosomal splic-ing have been found using this method, representing addi-tional confirmation of the existence of cross-chromosomalsplicing events provided by bioinformatics tools. Since noconserved motif has been found in any of the eight instances,and at the same time current prediction algorithms produceonly trivial secondary structures at the "splicing sites", it isnot possible to identify any specific signal leading to thesplicing.     

细胞因子受体-抗人AFP嵌合抗体融合蛋白的构建及表达

用RT-PCR方法从人胎肝组织中扩增EpoR胞外区基因及gp130跨膜区基因,并用酶切连接方法将其与抗人AFP嵌合抗体拼接,连接到质粒pVITRO上,构建真核表达载体。将重组质粒转染CHO细胞,以RT-PCR、Western blot和ELISA方法检测融合蛋白的表达。结果显示稳定转染细胞株有约150kDa的融合蛋白表达。     

利用RT-PCR技术鉴定人ZP3嵌合肽基因在昆虫细胞中的表达

目的：探讨在转录水平上对人卵透明带蛋白3(hZP3)嵌合肽在昆虫细胞中的表达鉴定．方法：用含目的基因的重组病毒感染昆虫细胞，用LiCl法提取RNA，以其为模板，利用一步法RT-PCR反转录出目的DNA．结果：琼脂糖凝胶电泳显示其PCR产物只有一条DNA条带且与目的基因大小一致，而阴性对照未见任何条带．结论：hZP3嵌和肽基因在重组病毒感染的昆虫细胞中成功转录，初步验证了目的基因的表达．     

应用分子生物学方法诱导植物雄性不育:生物学基础和前景

本文着重介绍了花药和花粉发育过程中基因表达的特点和复杂性,花药和花粉的特异性基因以及特异性基因的调节等方面的研究进展,讨论了应用上述特异性基因的调节序列与一定的目的基因(如核糖核酸酶基因)构建的嵌合基因诱导植物雄性不育的前景和这种分子生物学方法在作物杂种优势利用过程中遇到的问题。     

Identification and characterization of CACTA transposable elements capturing gene fragments in maize

Transposable elements (TEs)-mediated gene sequence movement is thought to play an important role in genome expansion and origin of genes with novel functions. In this study, a gene, HGGT, involved in vitamin E synthesis was used in a case study to discover and characterize transposons carrying gene fragments in maize. A total of 69 transposons that are distributed across the 10 chromosomes and have an average length of 3689 bp were identified from the maize sequence database by using the BLAST search algori...     

抗人前列腺素D合成酶嵌合抗体基因的构建

采用RT-PCR技术,从1株稳定分泌抗人L-PGDS单克隆抗体的鼠杂交瘤细胞中扩增抗体的可变区基因,得2个Vk和1个VH．序列经Igblast比对分析,其中1个VK为鼠骨髓瘤细胞系内固有的无功能基因;另-Vk和VH具备鼠抗体可变区特征,为抗体功能基因．经双酶切,将抗体可变区功能基因分别与表达载体pAG4622、pAH4604中的人IgG相应恒定区相连,构建成抗人L-PGDS的人-鼠嵌合抗体基因。