杜氏盐藻核基质结合区的分离及其对转基因的表达调控作用

发布时间：2018-06-16 12:22

本文选题：杜氏盐藻 + 核基质结合区　；参考：《郑州大学》2005年博士论文

【摘要】：核基质结合区(matrix attachment regions, MARs)又叫核骨架附着区(scaffold attachment regions, SARs)是染色质被限制酶消化后仍与核基质或核骨架结合的DNA序列。MAR长度由300bp至2,000bp不等,通常富含AT碱基对,常含有一些特征性基序(motifs),如A-box(AATAAAAA/CAA)、T-box(TTTTATTTTT)、酵母自主复制序列(autonomously replicating DNA sequence, ARS)、果蝇拓朴异构酶Ⅱ(Topoisomerase Ⅱ)识别位点和能形成蛋白质识别位点的松散DNA(unwinding DNA)、弯曲DNA(curved DNA)等。MARs与核基质结合受AT区的位置及结构影响,其二级结构表现为狭窄的DNA小沟,易于弯曲和解链。MAR一般位于功能转录单位的侧翼,作为一种边界元件(boundary elements),但也有一些MAR位于某些基因的内含子中。虽然MAR具有一些序列特征,但比较不同MAR的碱基序列,发现MAR在碱基组成上并不具保守性。近年来研究发现,将MAR构建表达载体能提高外源基因的表达水平,增强外源基因表达的稳定性,克服外源基因沉默等。MAR还能使染色质形成环状结构,还可以作为DNA复制的起始点或调控基因的转录。但关于MAR的研究尚处于早期阶段,其分子调控机制目前仍不清楚。迄今已有一些MAR从酵母、动物、植物及人类中分离出来,并进行了其功能的相关研究,但目前所分离的MAR绝大多数来源于高等动植物,单细胞的真核生物研究的较少,真核藻类的MAR研究未见相关报道。高等动植物存在器官组织分化问题,不同的分化组织细胞基因表达的方式及其种类不同,MAR序列也可能存在差别。因此以单细胞的真核生物研究MAR的调控机制更具有特点及优势。杜氏盐藻(Dunaliella salina)是一种无细胞壁的单细胞绿藻,含有一个大的杯状叶绿体进行光合作用,具鞭毛,能游动,可在0.05～5M NaCl培养液中
[Abstract]:Nuclear matrix attachment regions (Mars), also known as scaffold attachment regions (Sars), are the sequences of chromatin that bind to nuclear matrix or nuclear skeleton after digestion by restriction enzymes. Mar length ranges from 300bp to 2000bp, and is usually rich in AT base pairs. It often contains some characteristic motifs, such as A-box A / CA A T T T, yeast autonomous replicating sequence, arsiella, Drosophila topoisomerase II) recognition sites, loose DNAs that form protein recognition sites, curved DNAs, and so on. Mars binds to nuclear matrix. The location and structure of AT area, Its secondary structure is a narrow DNA groove, which is easy to bend and unchain. Mar is generally located on the flank of the functional transcription unit as a boundary element, but some Mar is also located in the introns of some genes. Although Mar has some sequence characteristics, it is found that Mar is not conserved in base composition by comparing the sequences of different Mar bases. In recent years, it has been found that constructing expression vector of Mar can improve the expression level of exogenous gene, enhance the stability of exogenous gene expression, overcome the silencing of exogenous gene, and make chromatin form circular structure. It can also act as the starting point of DNA replication or regulate the transcription of genes. However, the study of Mar is still in its early stage, and its molecular regulation mechanism is still unclear. Up to now, some Mar has been isolated from yeast, animal, plant and human, and its function has been studied. The Mar study of eukaryotic algae has not been reported. Higher plants and animals have the problem of organ tissue differentiation, and the gene expression patterns and their types of genes in different differentiated tissues and cells may also be different. Therefore, the study of the regulation mechanism of Mar by single cell eukaryote has more characteristics and advantages. Dunaliella Salina (Dunaliella Salina) is a single-celled green algae with no cell wall. It contains a large goblet chloroplast for photosynthesis, flagellum, swimming, and can be found in 0.05m NaCl medium.
【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2005
【分类号】：R346

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