鲤鱼线粒体tRNA^CYS基因和轻链复制起始区的结构分析

我们测定了鲁鱼线粒体半胱氨酸ｔＲＮＡ基因和轻链复制起始区的核苷酸序列,绘制了半胱氨酸ｔＲＮＡ三叶草形的二级结构以及Ｌ链复制区的茎环结构。通过种脊椎动物ｔＲＮＡ＾ＣＹＳ基因的核苷酸序列分析发现,鲤鱼线粒体ｔＲＮＡ＾ＣＹＳ基因的不寻常的结构特点。鲤鱼线粒体Ｌ链复制起始区含有３６个碱基,复制起始区茎环名的茎含有１１对碱基,而环则是由１４个碱基组成。同其它１０种脊椎动物Ｌ－链复制起始区的核苷酸序列比较发现     

熊超科的分子系统发生研究

有关熊超科的系统发生与演化存在很多争议。本工作测定了黑足鼬、南方海狮和非洲猎犬线粒体细胞色素ｂ、１２ＳｒＲＮＡ、ｔＲＮＡｔｈｒ和ｔＲＮＡＰｒｏ基因片段的ＤＮＡ序列。结合我们过去确定的熊超科其他动物的ＤＮＡ序列,我们采用简约法和距离法构建了较为系统的熊超科分子系统树。结果表明：浣熊科与鼬科、熊科与大熊猫科分别具有较近的共同祖先;鳍脚类不是一个独立的目,它们应归入熊超科;鳍脚类可能是单起源的,它们与浣熊科和鼬科的关系较与其他科更紧密;小熊猫科与其他科的关系并不密切。     

鲤鱼线粒体tRNA~（phe）基因结构的特异性

在脊椎动物线粒体基因组的研究中,迄今为止已测定了人、牛、大鼠、爪蟾、鲸鱼、海豹、鸡等动物线粒体基因组的全序列。结果表明,脊椎动物线粒体基因组结构排列非常紧密。２２个ｔＲＮＡ基因分布于结构基因和ｒＲＮＡ基因之间,并随其临近的基因一起转录,随后被精确地剪切下来,继续加工成熟。线粒体ｔＲＮＡ与细胞质ｔＲＮＡ相比有许多不同之处,如：Ｄ环碱基数目明显减少;ＴΨＣ环中缺少Ｔ５４－Ｃ－Ｐｕ－Ａ序列;且各个臂上有高比例的碱基错配;同时在线粒体ｔＲＮＡ中Ａ＋Ｕ含量很高。目前有报道指出线粒体中某些ｔＲＮＡ三叶草结构的变化与物种的进化相关联,但这一说法是否具有普遍性尚须探讨。我们最近完成了鲤鱼线粒体ｔＲＮＡｐｈｅ基因的结构分析（图一）,并将其与上述已报导的几种脊椎动物线粒体ｔＲＮＡｐｈｅ基因进行了比较（表一）,发现这些ｔＲＮＡｐｈｅ基因的Ｄ臂上都存在一个１３ｂｐ的强保守区,而其它２１种线粒体ｔＲＮＡ基因上的这一区域却是最不保守的。我们将此保守区前７个碱基与真核生物ＲＮＡＰｏｌⅢ识别的Ａ区相比较,发现ＲＮＡＰｏｌⅢ识别的Ａ区的３个强保守碱基在碱基类型与碱基排列位置上完全与此保守区相同（图二）。考虑到ｔＲＮＡｐｈｅ基因在线粒体基因组     

马来熊的DNA序列分析与遗传多样性研究

马来熊在ＩＵＩＣＮ红皮中被列为受胁动物,其保护受到广泛的关注,本文研究了４只马来熊的线粒体ＤＮＡ序列,其中１只来自云南,其余３只产地不详,但来自不同的搜集渠道,对于每个个体,我们测定了３９７ｂｐ的细胞色素ｂ基因,３４６ｂｐ的１２ＳｒＲＮＡ基因,９８ｂｐ的ｔＲＮＡ基因和３３３ｂｐ的Ｄ环区序列,共计１１７４ｂｐ。经与黑犀牛序列比较,发现ＲＮＡ基因的空间结构对基因的进化有显著影响,环区的进化明显快于茎区     

鲤鱼线粒体tRNAphe基因结构的特异性

鲤鱼线粒体ｔＲＮＡｐｈｅ基因的核酸序列已被测定。在鲸、人、抓蟾、牛、小鼠、鸡和锂鱼中对此基因序列比较发现在Ｄ茎存在一个奇怪的保守结构,然而Ｄ茎在其余种类的已经测定的脊椎动物线粒体ｔＲＮＡ基因和细胞质ｔＲＮＡ基因中是极不保守的。这一保结构饮食有１３ｂｐ碱基,我们将此保守区前７个碱基与真核生物ＲＮＡＰｏｌⅢ识别的Ａ区要比较, 此不同物种的两种序列存在部分的同源性。考虑到ｔＲＮＡｐｈｅ基因在编码区之间这     

豌豆5SrRNA的cDNA克隆、全序列及结构特征分析

以赤霉素（ＧＡ）处理后的Ｇ２豌豆为材料,构建了一个２．０×１０６的ｃＤＮＡ文库,用随机筛选法从该ｃＤＮＡ文库中得到一个完整的ｃＤＮＡ．其中１１１５ｂｐ全序列分析表明,它编码了豌豆５Ｓ核糖体ＲＮＡ（５ＳｒｉｂｏｓｏｍａｌＲＮＡ,５ＳｒＲＮＡ）,基因内部存在着与核糖体蛋白Ｌ５及５ＳｒＲＮＡ结合蛋白（５ＳｒＲＮＡＢｉｎｄｉｎｇＰｒｏｔｅｉｎ）同源的区段,这些同源区段是蛋白与ＲＮＡ结合的位点．基因内部还存在着大量的重复序列．     

一组丝瓜籽小分子核糖体失活蛋白LuffinS的分离,纯化 …

通过硫酸铵分级沉淀、ＣＭ－５２阳离子交换层析、ＨＲＬＣ分子排阻层析及ＦＰＬＣ Ｍｏｎｏ Ｓ离子交换层析等步骤,从丝瓜籽中分离到一组分子量为８ｋＤ左右的小分子核糖体失活蛋白－ＬｕｆｆｉｎＳ１、ＬｕｆｆｉｎＳ２、ＬｕｆｆｉｎＳ３。末端分析结果表明,它们的Ｎ端氨基酸分别为Ａｌａ、Ｐｒｏ和Ｔｈｒ。氨基酸序列分析确定了ＬｕｆｆｉｎＳ２的Ｎ端９个氨基酸的序列是Ｐｒｏ－Ａｒｇ－Ｇｌｙ－Ｇｌｎ－Ａｌａ－Ｐｈｅ－Ａ     

线粒体和细胞核的互作

线粒体是一个半自主的细胞器,它有自己的基因组,能进行ＤＮＡ的复制、转录和翻译,可以编码自身的ｒＲＮＡ、ｔＲＮＡ以及少量蛋白质。但这些过程并不是线粒体完全独立地进行的,它离不开核基因组的指导与调控。线粒体基因表达所必需的一些蛋白质,如ＲＮＡ聚合酶、核糖体大亚单位以及许多调控因子都是由核基因编码,在细胞质的核糖体上合成后,运输进线粒体后再起作用。线粒体功能的正常发挥需要线粒体基因组和核基因组的互作。组成呼吸链的一系列结构蛋白是由线粒体和细胞核共同编码的,这些蛋白质的正确组装,受核基因的控制。同时,研…     

瓦草中三个新环肽

从云南民间中草药瓦草（Ｓｉｌｅｎｅｓｚｅｃｈｕｅｎｓｉｓ）的根中分离鉴定了３个新的环肽,分别命名为瓦草环肽Ａ,Ｂ,Ｃ（ｓｉｌｅｎｉｎｓＡ,Ｂ,Ｃ）用光谱和化学方法确定它们均为环八肽,其结构分别为：ｓｉｌｅｎｉａＡ－ｃｙｃｌｏ－（Ｐｒｏ－Ｌｅｕ－Ｓｅｒ－Ｐｈｅ－Ｐｒｏ－Ｔｙｒ－Ｌｅｕ－Ｖａｌ）,ｓｉｌｅｎｉｎＢ－－ｃｙｃｌｏ－（Ｐｈｅ－Ｌｅｕ－Ａｌａ－Ｐｒｏ－Ｌｅｕ－Ｐｒｏ－Ｐｈｅ－Ｐｒｏ）,ｓｉｌ     

CAR－bacillus菌亚单位核糖核酸RNA限制性内切酶图谱的研究

利用生物体中编码亚单位核糖核酸ＲＮＡ（ｓｍａｌｌｓｕｂｕｎｉｔｒｉｂｏｓｏｍａｌ　ＲＮＡ,ＳＳＵｒＲＮＡ）的ＤＮＡ序列为引物,经ＰＣＲ法扩增到ＣＡＲ－ｂａｃｉｌｌｕｓ的大约１．５ｋｂ的ＳＳＵｒＲＮＡ序列,采用ＨｉｎｄⅡ、ＨｉｎｆⅠ、ＥｃｏＴ１４,ＨａｅⅢ和ｘｈｏⅠ等５种限制性内切酶进行酶切电泳分析,同时比较了来源于小鼠的ＣＢＭ株及来源于大鼠的ＣＢＲ株,未发现两者有差异。     

Gene rearrangements in snake mitochondrial genomes: highly concerted evolution of control-region-like sequences duplicated and inserted into a tRNA gene cluster

Mitochondrial DNA (mtDNA) regions corresponding to two major tRNA gene clusters were amplified and sequenced for the Japanese pit viper, himehabu. In one of these clusters, which in most vertebrates characterized to date contains three tightly connected genes for tRNA(Ile), and tRNA(Gln), and tRNA(Met), a sequence of approximately 1.3 kb was found to be inserted between the genes for tRNA(Ile) and tRNA(Gln). The insert consists of a control-region-like sequence possessing some conserved sequence blocks, and short flanking sequences which may be folded into tRNA(Pro), tRNA(Phe), and tRNA(Leu) genes. Several other snakes belonging to different families were also found to possess a control-region-like sequence and tRNA(Leu) gene between the tRNA(Ile)and tRNA(Gln) genes. We also sequenced a region surrounded by genes for cytochrome b and 12S rRNA, where the control region and genes for tRNA(Pro) and tRNA(Phe) are normally located in the mtDNAs of most vertebrates. In this region of three examined snakes, a control-region- like sequence exists that is almost completely identical to the one found between the tRNA(Ile) and tRNA(Gln) genes. The mtDNAs of these snakes thus possess two nearly identical control-region-like sequences which are otherwise divergent to a large extent between the species. These results suggest that the duplicate state of the control-region- like sequences has long persisted in snake mtDNAs, possibly since the original insertion of the control-region-like sequence and tRNA(Leu) gene into the tRNA gene cluster, which occurred in the early stage of the divergence of snakes. It is also suggested that the duplicated control-region-like sequences at two distant locations of mtDNA have evolved concertedly by a mechanism such as frequent gene conversion. The secondary structures of the determined tRNA genes point to the operation of simplification pressure on the T psi C arm of snake mitochondrial tRNAs.      

基于第二代测序技术兰州鲇线粒体基因组全序列测定与分析

研究采用高通量第二代测序技术,构建获得兰州鲇（Silurus lanzhouensis）线粒体基因组全序列,并对全序列特征和结构进行了分析。研究结果表明,兰州鲇线粒体基因组全序列长度为16523 bp,碱基组成具有高A+T低G+C含量的偏向性,具有脊椎动物典型的结构组成。13个PCG基因中存在2种启动子（ATG、GTG）、3种终止子（TAG、TAA和T或TA）。除tRNA-Ser（AGN）基因二级结构中DHU臂缺失,其余21个tRNA基因可折叠成典型三叶草结构。12S rRNA二级结构由45个茎环结构组成4个结构域,16S rRNA由54个茎环结构组成6个结构域。含有关键序列标签的控制区（CR）可分为3个不同的结构域:终止序列区（TAS1、TAS2）、中央保守区（CSB-F、CSB-E和CSB-D）和保守序列区（CSB1、CSB2和CSB3）。非编码区含有一段保守的控制轻链复制起始的序列区（O_L）。基于线粒体基因组全序列和通用标签COX1基因标记可区分兰州鲇同其他鲇形目鱼类种质进化关系。     

Sequence variation and structural conservation in the D-loop region and flanking genes of mitochondrial DNA from Japanese pond frogs

The nucleotide sequences of the D-loop region and its flanking genes of the mitochondrial DNA (mtDNA) from Japanese pond frogs were determined by the methods of PCR, cloning, and sequencing. The frogs belonged to two species, one subspecies, and one local race. The gene arrangements adjacent to the D-loop region were analyzed. The frogs shared a unique mitochondrial gene order that was found in Rana catesbeiana; i.e., cyt b--D-loop region--tRNA(Leu(CUN))--tRNA(Thr)--tRNA(Pro)--tRNA(Phe)--12S rRNA. The arrangements of the three tRNA genes of these frogs were different from those of X. laevis, a species which has the same overall structure as in mammals. Highly repetitive sequences with repeat units (16-bp or 17-bp sequence specific for each taxon) were found in the D-loop region. The length of repetitive sequences varied from 0.6 kbp to 1.2 kbp, and caused the extensive size variation in mtDNA. Several short sequence elements such as putative TAS, OH, CSB-1, and CSB-2 were found in the D-loop region of these frogs. The sequences of these short regulatory elements were conserved in R. catesbeiana, X. laevis, and also in human. The comparison of sequence divergences of the D-loop region and its adjacent genes among various taxa revealed that the rates of nucleotide substitutions depend on genes. The nucleotide sequences of the 3'-side segment of the D-loop region were the most variable among taxa, whereas those of the tRNA and 12S rRNA genes were the most conservative.     

The complete mitochondrial genome of the marbled rockfish Sebastiscus marmoratus (Scorpaeniformes, Scorpaenidae): genome characterization and phylogenetic considerations

The complete mitochondrial genome sequence of the marbled rockfish Sebastiscus marmoratus (Scorpaeniformes, Scorpaenidae) was determined and phylogenetic analysis was conducted to elucidate the evolutionary relationship of the marbled rockfish with other Sebastinae species. This mitochondrial genome, consisting of 17301 bp, is highly similar to that of most other vertebrates, containing the same gene order and an identical number of genes or regions, including 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, and one putative control region. Most of the genes are encoded on the H-strand, while the ND6 and seven tRNA genes (for Gln, Ala, Asn, Tyr, Ser (UCA), Glu, and Pro) are encoded on the L-strand. The reading frame of two pairs of genes overlapped on the same strand (the ATPase 8 and 6 genes overlapped by ten nucleotides; ND4L and ND4 genes overlapped by seven nucleotides). The possibly nonfunctional light-strand replication origin folded into a typical stem-loop secondary structure and a conserved motif (5'-GCCGG-3') was found at the base of the stem within the tRNA(Cys) gene. An extent termination-associated sequence (ETAS) and conserved sequence blocks (CSB) were identified in the control region, except for CSB-1; unusual long tandem repeats were found at the 3' end of the control region. Phylogenetic analyses supported the view that Sebastinae comprises four genera (Sebates, Hozukius, Helicolenus, and Sebasticus).     

Rearrangements of mitochondrial transfer RNA genes in marsupials

Summary The nucleotide sequences of the mitochondrial origin of light-strand replication and the five tRNA genes surrounding it were determined for three marsupials. The region was found to be rearranged, leaving only the tRNA^Tyr gene at the same position as in placental mammals andXenopus. Distribution of the same rearranged genotype among two marsupial families indicates that the events causing the rearrangements took place in an early marsupial ancestor. The putative mitochondrial light-strand origin of replication in marsupials contains a hairpin structure similar to other vertebrate origins and, in addition, extensive flanking sequences that are not found in other vertebrates. Sequence comparisons among the marsupials as well as placentals indicate that the tRNA^Tyr gene has been evolving under more constraints than the other tRNA genes.Deceased July 21, 1991     

The complete mitochondrial genome of the marbled rockfish <Emphasis Type="Italic">Sebastiscus marmoratus</Emphasis> (Scorpaeniformes,Scorpaenidae): Genome characterization and phylogenetic considerations

The complete mitochondrial genome sequence of the marbled rockfish Sebastiscus marmoratus (Scorpaeniformes, Scorpaenidae) was determined and phylogenetic analysis was conducted to elucidate the evolutionary relationship of the marbled rockfish with other Sebastinae species. This mitochondrial genome, consisting of 17301 bp, is highly similar to that of most other vertebrates, containing the same gene order and an identical number of genes or regions, including 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, and one putative control region. Most of the genes are encoded on the H-strand, while the ND6 and seven tRNA genes (for Gln, Ala, Asn, Tyr, Ser (UCA), Glu, and Pro) are encoded on the L-strand. The reading frame of two pairs of genes overlapped on the same strand (the ATPase 8 and 6 genes overlapped by ten nucleotides; ND4L and ND4 genes overlapped by seven nucleotides). The possibly nonfunctional light-strand replication origin folded into a typical stem-loop secondary structure and a conserved motif (5′-GCCGG-3′) was found at the base of the stem within the tRNA^Cys gene. An extent termination-associated sequence (ETAS) and conserved sequence blocks (CSB) were identified in the control region, except for CSB-1; unusual long tandem repeats were found at the 3′ end of the control region. Phylogenetic analyses supported the view that Sebastinae comprises four genera (Sebastes, Hozukius, Helicolenus, and Sebastiscus).     

The complete mitochondrial genomes of two schizothoracine fishes (Teleostei,Cypriniformes): A novel minisatellite in fish mitochondrial genomes

Minisatellites, a class of variable number tandem repeats (VNTRs), are abundant throughout the control region in animal mitochondrial DNA (mtDNA) but rare in other regions of animal mtDNA. Here, we reported a novel minisatellite in fish mitochondrial genomes. We first determined the complete mitochondrial genomes of two schizothoracine fishes (Herzensteinia microcephalus and Schizopygopsis pylzovi) and found a type of minisatellites in a novel region between the tRNA‐Thr and tRNA‐Pro genes in their mtDNA. To explore the origin and evolution of the minisatellites in different schizothoracine and closely related fishes, we analyzed the available 80 fish mitogenomes which represent five closely related tribes of cyprinine fishes. The results from the phylogenetic analyses show that the schizothoracine fishes sensu stricto is not a monophyletic group and is divided into two clades (Schizothoracini and Schizopygopsini); and the minisatellite is only present in Schizopygopsini distributed in the region between the two tRNA genes (tRNA‐Thr and tRNA‐Pro) of the mtDNA. This is the first record of a minisatellite in a non‐control region of fish mitogenome.     

Editing corrects mispairing in the acceptor stem of bean and potato mitochondrial phenylalanine transfer RNAs.

Editing is a general event in plant mitochondrial messenger RNAs, but has never been detected in a plant mitochondrial transfer RNA (tRNA). We demonstrate here the occurrence of a tRNA editing event in higher plant mitochondria: in both bean and potato, the C encoded at position 4 in the mitochondrial tRNA(Phe)(GAA) gene is converted into a U in the mature tRNA. This nucleotide change corrects the mismatched C4-A69 base-pair which appears when folding the gene sequence into the cloverleaf structure and it is consistent with the fact that C to U transitions constitute the common editing events affecting plant mitochondrial messenger RNAs. The tRNA(Phe)(GAA) gene is located upstream of the single copy tRNA(Pro)(UGG) gene in both the potato and the bean mitochondrial DNAs. The sequences of potato and bean tRNA(Pro)(UGG) genes are colinear with the sequence of the mature bean mitochondrial tRNA(Pro)(UGG), demonstrating that this tRNA is not edited. A single copy tRNA(Ser)(GCU) gene was found upstream of the tRNA(Phe) gene in the potato mitochondrial DNA. A U6-U67 mismatched base-pair appears in the cloverleaf folding of this gene and is maintained in the mature potato mitochondrial tRNA(Ser)(GCU), which argues in favour of the hypothesis that the editing system of plant mitochondria can only perform C to U or occasionally U to C changes.     

Cloning and characterization of a microsatellite in the mitochondrial control region of the African side-necked turtle,Pelomedusa subrufa

The nucleotide sequence of the African side-necked turtle mitochondrial control region and its flanking tRNA genes was determined. This 73% A+T-rich region is 1194 bp long. Several conserved motifs involved in the regulation of the mitochondrial genome replication process, including one conserved sequence block (CSB1), and three termination-associated sequences were identified. The most remarkable feature found in this control region was the presence of six microsatellite-containing tandem repeats between the CSB1 motif and the tRNA^Phe gene. The potential usefulness of this microsatellite sequence for population-level studies is enhanced by its unique localization in the maternally inherited mitochondrial molecule.