水稻基因组测序的研究进展

水稻是最重要的粮食作物之一,世界上大约有一半的人口以水稻为主要粮食。作为基因组研究的模式植物,水稻基因组的测序工作已在世界范围内展开。此项研究工作不仅能破译水稻全基因组序列,还将有助于了解其他禾本科植物的基因组信息。本对水稻基因组测序工作进展作一综述。     

水稻转座子Tourist—Os6从sbe1基因启动区切离的证明

为研究ｓｂｅｅ１基因的表达调控机理,籼稻ＩＲ３６品种的ｓｂｅ１基因被克隆。经测序一与已报告的ｓｂｅ１上比,ＩＲ３６水稻品种ｓｈｅ１基因５‘上游区顺序中除了有分散的３２个碱基差异外,值得注意的是缺少一般３３５ｂｐ长的Ｔｏｕｒｉｓｔ－Ｏｓ６序列,并在缺失的位置上留下转座子切离后的特征性足印顺序,这表明ＩＲ３６品种的Ｔｏｕｒｉｓｔ－Ｏｓ６已从ｓｂｅ１基因中切离。因而为Ｔｏｕｒｉｓｔ－Ｏｓ６是可移动的转座     

水稻基因组物理图的构建

水稻基因组物理图的构建中国科学院国家基因研究中心（上海，２００２３３）关键词水稻基因组物理图我国是水稻栽植国家，约有一半人口以水稻为主食。地球上大约也有一半的人口以水稻为主食。根据我国国情和科学发展的现状和趋势，国家科委于１９９２年８月正式宣布在我国...     

丙型肝炎病毒基因组部份NS5区蛋白基因在大肠杆菌中的表达

在大肠杆菌中表达了丙型肝炎病毒基因组ＮＳ５区Ａ段和部份Ｂ段蛋白。ＮＳ５Ａ蛋白溶于水,可经过ＧＳＴ亲和层析柱纯化;ＮＳ５Ｂ蛋白不溶于水,经ＰＢＳ－Ｔｒｉｔｏｎ Ｘ－１００洗涤,尿素溶解后,通过离子交换柱纯化。经ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｍｂｌｏｔ分析,ＮＳ５Ａ蛋白除在５７ｋＤ左右有条带外,还有不同程度的降解产物;ＮＳ５Ｂ蛋白主要在５８ｋＤ左右有条带出现。为查明表达蛋白抗体在病人血清中的分布,取９     

水稻基因组测序的研究进展

水稻是最重要的粮食作物之一,世界上大约有一半的人口以水稻为主要粮食.作为基因组研究的模式植物,水稻基因组的测序工作已在世界范围内展开.此项研究工作不仅能破译水稻全基因组序列,还将有助于了解其他禾本科植物的基因组信息.本文对水稻基因组测序工作进展作一综述。 Abstract:Because of the importamce of rice as the staple food source for over half of the world population and since rice is a leading model plant for genomic studies,an international effort has now begun to sequence the rice genome.This project eventually will reveal all of the genomic sequence information of rice and be an indispensable aid in understanding the genomics of other grass species.In this paper,the development and research progress in sequencing of rice genome are reviewed.     

PSIIP680 ChlaAP基因在水稻叶绿体基因组中的定位

本实验总结出一套水稻叶绿体DNA的提取方法,并获得清晰的叶绿体DNA限制性内切酶图谱。Southern杂交结果表明,菠菜PSIIP680ChlaAP基因探针与水稻叶绿体DNA的Pst-1,Pst-14,Pvu-2和Sal-1片段的部分顺序有较高的同源性。根据Hirai和赵衍的水稻叶绿体基因组物理图,可以确定该基因位于紧靠RuBPCaseLS基因,距反向重复区约26kb处。高等植物叶绿体基因组中这种基因排列方式还未见报道。     

The Importance of Genome Architecture in Cancer Susceptibility: Location,Location, Location

Tumorigenesis requires the interaction between different gene disruptions to convert anormal cell into a cancer cell. These gene disruptions can involve loss of expression ormisexpression of genes through genetic or epigenetic mutations. It is becoming clear that thesedisruptions are not isolated events in the genome, but are affected by genome architecture andthe syntenic relationship of alleles on chromosomes. A better understanding of the genetic andepigenetic changes in cancer is important for the rational design of new therapies. We haverecently shown that background-specific polymorphisms and loci under epigenetic regulationhave a strong effect on cancer susceptibility in a mouse model of astrocytoma. Although thesemice carry mutations in p53 and ras signaling pathways (through mutation of the rasGAPprotein, Nf1), the susceptibility to different tumor types depends strongly on epigeneticregulation and does not show simple Mendelian inheritance. Our results demonstrate theimportance of genome architecture and how tumorigenesis can be accelerated by concomitantloss or gain of multiple genes in a single chromosome rearrangement. Because genomearchitecture is very different between mice and humans, comparing patterns of genomicrearrangement in human cancer and mouse models may help distinguish causal genomic changesfrom correlative changes.     

T-DNA标签在转基因水稻基因组中的整合特点

利用热不对称交错PCR (TAIL-PCR),对200个含T-DNA插入的转基因水稻株系进行分析,获得了159个T-DNA右边界侧翼序列. 其中,92个序列含有T-DNA右边界和侧邻的水稻基因组序列,78个序列与已公布的水稻BAC/PAC克隆有97%～100%的同源性,从而可作为T-DNA标签定位在水稻的12条染色体上. 结合先前定位的169个T-DNA标签,对T-DNA在水稻基因组中的整合特点进行了分析. 结果发现,在T-DNA右边界和侧邻的水稻基因组序列的连接处,14.6%的T-DNA标签含有3～74bp的填充序列. 在不含填充序列的连接处,21.3%的T-DNA标签,在整合后的T-DNA右边界与侧翼的水稻基因组序列之间显示出3～5 bp的微同源性. 填充序列和微同源性的存在,揭示了T-DNA在水稻基因组中的整合既存在双链断裂修补机制,又存在单链裂缝修补机制. T-DNA倾向于整合到富含A/T核苷酸的基因组区域,即主要在基因的5′和3′端调控区以及内含子中.     

水稻基因组中的节段重复

利用１３个多拷贝探针,研究水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）基因组第８、９、１１和１２染色体上的节段重复。由同一探针检测到的多拷贝位点通常位于不同染色体的相同部位。不同探针检测到的多拷贝位点在不同染色体上的位置顺序相同。第８种９染色体上的相同多拷贝位点的线性排列,提示这两条染色体在进行上可能来源于同一原始染色体。而第９染色体上的一个节段与前人报道的以及本研究进一步证实的第１１和第１２染色体短臂     

Segmental Duplications Are Common in Rice Genome

Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.     

T-DNA Integration Category and Mechanism in Rice Genome

T-DNA integration is a key step in the process of plant transformation, which is proven to be important for analyzing T-DNA integration mechanism. The structures of T-DNA right borders inserted into the rice (Oryza sativa L.) genome and their flanking sequences were analyzed. It was found that the integrated ends of the T-DNA right border occurred mainly on five nucleotides "TGACA" in inverse repeat (IR)sequence of 25 bp, especially on the third base "A". However, the integrated ends would sometimes lie inward of the IR sequence, which caused the IR sequence to be lost completely. Sometimes the right integrated ends appeared on the vector sequences rightward of the T-DNA right border, which made the TDNA, carrying vector sequences, integrated into the rice genome. These results seemingly suggest that the IR sequence of the right border plays an important role in the process of T-DNA integration into the rice genome, but is not an essential element. The appearance of vector sequences neighboring the T-DNA right border suggested that before being transferred into the plant cell from Agrobacterium, the entire T-DNA possibly began from the left border in synthesis and then read through at the right border. Several nucleotides in the T-DNA right border homologous with plant DNA and filler DNAs were frequently discovered in the integrated position ofT-DNA. Some small regions in the right border could match with the plant sequence, or form better matches, accompanied by the occurrence of filler DNA, through mutual twisting, and then the TDNA was integrated into plant chromosome through a partially homologous recombination mechanism. The appearance of filler DNA would facilitate T-DNA integration. The fragments flanking the T-DNA right border in transformed rice plants could derive from different parts of the inner T-DNA region; that is, disruption and recombination could occur at arbitrary positions in the entire T-DNA, in which the homologous area was comparatively easier to be disrupted. The structure of flanking sequences of T-DNA integrated in the rice chromosome presented various complexities. These complexities were probably a result of different patterns of recombination in the integrating process. Some types of possible integrating mechanism are detailed.     

T-DNA Integration Category and Mechanism in Rice Genome

T-DNA integration is a key step in the process of plant transformation, which is proven to be important for analyzing T-DNA integration mechanism. The structures of T-DNA right borders inserted into the rice (Oryza sativa L.) genome and their flanking sequences were analyzed. It was found that the integrated ends of the T-DNA right border occurred mainly on five nucleotides “TGACA” in inverse repeat (IR) sequence of 25 bp, especially on the third base “A”. However, the integrated ends would sometimes lie inward of the IR sequence, which caused the IR sequence to be lost completely. Sometimes the right integrated ends appeared on the vector sequences rightward of the T-DNA right border, which made the T-DNA, carrying vector sequences, integrated into the rice genome. These results seemingly suggest that the IR sequence of the right border plays an important role in the process of T-DNA integration into the rice genome, but is not an essential element. The appearance of vector sequences neighboring the T-DNA right border suggested that before being transferred into the plant cell from Agrobacterium, the entire T-DNA possibly began from the left border in synthesis and then read through at the right border. Several nucleotides in the T-DNA right border homologous with plant DNA and filler DNAs were frequently discovered in the integrated position of T-DNA. Some small regions in the fight border could match with the plant sequence, or form better matches, accompanied by the occurrence of filler DNA, through mutual twisting, and then the T-DNA was integrated into plant chromosome through a partially homologous recombination mechanism. The appearance of filler DNA would facilitate T-DNA integration. The fragments flanking the T-DNA fight border in transformed rice plants could derive from different parts of the inner T-DNA region; that is, disruption and recombination could occur at arbitrary positions in the entire T-DNA, in which the homologous area was comparatively easier to be disrupted. The structure of flanking sequences of T-DNA integrated in the rice chromosome presented various complexities. These complexities were probably a result of different patterns of recombination in the integrating process. Some types of possible integrating mechanism are detailed.