甘蓝型油菜细胞质雄性不育系301A线粒体不育基因片段分析

提取细胞质雄性不育系301A、212A和'陕3A'及其共同保持系'中双2号'线粒体DNA,根据已报道的Polima油菜细胞质雄性不育相关基因orf224序列设计引物,对3种不同来源的线粒体DNA PCR产物进行分析.结果显示,这3种甘蓝型油菜细胞质雄性不育材料所获得片段序列完全一致,且与已报道的Polima油菜线粒体中细胞质雄性不育相关基因orf224序列完全相同.研究表明,不育材料301A从分子角度讲属于Polima系统,不育系301A、212A和'陕3A'线粒体中与细胞质雄性不育相关线粒体基因片段orf224具有高度同源性.     

植物线粒体DNA质粒研究进展

本文列出了已发现的高等植物中的线粒体DNA质粒,按分子形状分为线粒体环状DNA质粒和线粒体线状DNA质粒,环状线粒体DNA质粒的特征是分子较小, 序列中有正向/反向重复序列,ORF一般较小。线状线粒体DNA质粒的特征是分子较大,末端有重复序列,5'端与蛋白质共价结合,有较长的ORF。还分别介绍了它们的复制机制、转录和起源。质粒间及质粒与核基因组、线粒体基因组、叶绿体基因组的同源性也作了介绍。最后,综述了植物线粒体DNA质粒与植物的细胞质雄性不育（CMS）之间的关系。     

猕猴桃属植物线粒体DNA片段PCR-RFLP研究初报

猕猴桃属 ( Actinidia)植物 ,全世界有 66个种 ,约 1 1 8个种下分类单位 (变种、变型 ) [1] 。近来通过对猕猴桃属植物的细胞质 DNA研究证实 ,该属植物细胞质 DNA为单亲遗传 ,其线粒体 DNA为严格的母性遗传 [2 ] ,这一单亲遗传特性为研究猕猴桃属植物分类及系统学提供了新的途径。在高等植物中 ,由于线粒体 DNA的高度保守 ,以及重排率高而突变率低 ,加之在植物组织中的含量较低 ,限制了它在系统学研究中的应用 ,不适合属以上高阶元间的比较研究[3 ] ,但线粒体 DNA序列进化速度快 ,在近缘种内或种间显示出了更大的变异性 ,并且线粒体 …     

线粒体DNA及其应用

线粒体DNA是在真核生物中普遍存在的一种核外遗传物质,具有分子小、结构简单、进化速度快、母性遗传、无组织特异性等特点。本综述了线粒体DNA在人类遗传疾病、动植物的亲缘关系、种群分化、群体多样性及植物细胞质雄性不育等研究领域中的应用情况。     

黄瓜生殖细胞分离及其线粒体DNA的观察与拷贝数定量分析

该研究以6～8月上午10点左右摘取的新鲜黄瓜花朵为材料,采用渗透压冲击的方法分离黄瓜生殖细胞,并应用竞争型定量PCR技术测定其线粒体DNA数量,分析生殖细胞在发育过程中线粒体DNA的变化,以明确高丰度线粒体DNA的来源,为进一步研究被子植物调控线粒体DNA扩增的分子机制奠定基础。结果显示:(1)DAPI染色观察发现,黄瓜生殖细胞的细胞核周围存在大量的细胞器DNA荧光点,表明黄瓜生殖细胞的细胞质中存在大量的线粒体DNA。(2)成熟黄瓜生殖细胞平均包含(1 037±126)个线粒体DNA拷贝。(3)成熟生殖细胞内线粒体DNA含量为早期生殖细胞的14.5倍,表明成熟生殖细胞中的线粒体DNA主要来自于生殖细胞形成后其内活跃的线粒体DNA扩增。研究认为,黄瓜生殖细胞内活跃的线粒体DNA是黄瓜线粒体父系遗传的基础。     

用线粒体DNA鉴定玉米雄性不育细胞质的研究

参照Kemble法,通过分析玉米线粒体DNA,鉴定出我国生产上应用的玉米双型和唐徐型雄性不育细胞质属于S组。近年新获得的不育类型Y型属于T组,为玉米种子生产合理应用雄性不育细胞质提供了可靠依据,并对鉴别玉米雄性不育细胞质的方法进行了讨论。     

线粒体与卵母细胞发育

卵子发育、成熟是一个复杂的过程, 细胞核成熟和细胞质成熟过程必须同步化, 才能保证卵子的正常受精和进一步的发育。作为细胞质内最重要的细胞器, 线粒体在卵子成熟过程中的分布的变化、氧化磷酸化产生ATP的能力以及线粒体ＤＮＡ的含量和拷贝数或转录水平对卵母细胞发育成熟有着重要的影响。因此, 对卵子成熟过程中线粒体的分布和功能状况及线粒体DNA的研究, 有利于进一步了解生殖生理, 并为解决辅助生殖技术中及克隆胚胎技术所面临的困难提供新的思路。     

红莲型细胞质雄性不育水稻线粒体DNA的AP-PCR分析

为了研究红莲型细胞质雄性不育与线粒体基因组的关系。以水稻红莲型粤泰细胞质雄性不育系A和保持系B及杂种一代F1为材料。应用AP-PCR分析,用10个单引物对其线粒体DNA进行扩增。实验结果表明,不同的引物在3种材料间均有不同程度的差异。为红莲型细胞质雄性不育分子机理的研究提供了线索;此外,在引物6F1的扩增图谱中找到一条在YTA和F1中特异的带TAF6F2,Sounthern分析TAF6F2不育胞质的特异性,可能与红莲型水稻细胞质雄性 不育性状的形成有关。     

植物细胞质雄性不育分子机理研究进展

本文从线粒体基因组、线粒体基因、线粒体转录RNA、线粒体蛋白、转基因植物以及花粉败育机理六个方面详细介绍了植物细胞质雄性不育分子生物学研究的技术和方法。综述了植物细胞质雄性不育分子机理研究的进展 ,并对植物细胞质雄性不育分子机理的前景作了展望。     

植物细胞质雄性不育分子机理研究进展

本文从线粒体基因组、线粒体基因、线粒体转录 RNA、 线粒体蛋白、转基因植物以及花粉败育机理六个方面详细介绍了植物细胞质雄性不育分子生物学研究的技术和方法。综述了植物细胞质雄性不育分子机理研究的进展,并对植物细胞质雄性不育分子机理的前景作了展望。     

Reassociation and dissociation of cytoplasmic membrane-associated DNA

The relationship between nuclear DNA and cytoplasmic membrane-associated DNA, extracted from a human lymphocyte cell line, was examined by DNA-DNA reannealing and by dissociation of renatured molecules. Up to 2% of the total cellular DNA is found in the cytoplasm as cytoplasmic membrane-associated DNA and of this 2%, approximately 70% is comprised of repeated sequences. These sequences are homologous to only about 4% of the repeated sequences of nuclear DNA. The repeat fraction of cytoplasmic membrane-associated DNA consists of sequences which are only moderately repeated. The number of copies in the average “family” could range from about 1500 copies to as few as 25 copies. A small rapidly reannealing portion of cytoplasmic membrane-associated DNA (C₀t < 4 × 10^?3) appears to consist of sequences derived from a single “family”.About 30% of cytoplasmic membrane-associated DNA reassociates slowly with a $\text{C}{}_0\text{t}\text{1}\text{2}$ value of 223 (unique cytoplasmic membrane-associated DNA). This fraction has homology with about 11% of the unique sequences of nuclear DNA. However, unique cytoplasmic membrane-associated DNA comprises only about 0·6% of the total cellular DNA. If it is assumed that each cell has the same amount of cytoplasmic membrane-associated DNA, homology with 11% of the unique sequences of nuclear DNA suggests that different cells may have different unique nucleotide sequences in the cytoplasm.     

Organelle DNA polymorphism in apple cultivars and rootstocks

Summary Restriction fragment length polymorphisms (RFLPs) have been used to detect chloroplast (cp) and mitochondrial (mt) DNA variation among 18 apple cultivars and three rootstocks. The distribution of RFLP patterns allowed the assignment of these genotypes into three groups of cytoplasmic relatedness. Our results also demonstrate maternal inheritance of cp- and mtDNAs in apple. Thus, the organelle DNA assay provides a convenient and reliable method to assess cytoplasmic diversity within the apple germ-plasm collection and to trace the maternal lineages involved in the evolution of apple.     

Mitochondrial DNA modifications associated with cytoplasmic male sterility in rice

Summary Mitochondrial DNA was isolated from fertile and cytoplasmic male sterile lines of rice. Restriction analysis showed specific modifications in the male sterile cytoplasm. In addition to the major mitochondrial DNA, three small plasmid-like DNA molecules were detected by agarose gel electrophoresis in both cytoplasms. An additional molecule was specifically found in the sterile cytoplasm. These mitochondrial DNA modifications support the hypothesis of the mitochondrial inheritance of the cytoplasmic male sterility in rice.     

旋花科植物雄性细胞的细胞质DNA存在状况及其系统学意义

用DAPI荧光染色方法检测了旋花科4属4种植物——空心菜Ipomoea aquatica Forsk. 、茑萝 Qua- moclit pennata (Desr．)Boj．、月光花 Calonyction aculeatum(L．)House和日本菟丝子Cuscuta japonica Choisy 中生殖细胞和精细胞中细胞质DNA存在的状况。证明除日本菟丝子外,其余3种植物的雄性细胞中都 存在细胞质DNA。此外,在我们曾研究过的5种旋花科种植物的生殖细胞和精细胞中亦显示含有细胞质 DNA,因而可认为这是旋花科较普遍的特性,日本菟丝子精细胞中缺少细胞质DNA,可作为—个新的胚胎学证据,支持此属从旋花科分出独立为菟丝子科。     

Mitochondrial DNA polymorphism induced by protoplast fusion in Cruciferae

Summary The mitochondrial genomes of five rapeseed somatic hybrid plants, which combine in a first experimentBrassica napus chloroplasts and a cytoplasmic male sterility trait coming fromRaphanus sativus, and in a second experiment chloroplasts of a triazine resistantB. compestris and a cytoplasmic male sterility trait fromR. sativus, were analyzed by restriction endonucleases. Restriction fragment patterns indicate that these genomes differ from each other and from both parents. The presence of new bands in the somatic hybrid mitochondrial DNA restriction patterns is evidence of mitochondrial recombination in somatic hybrid cells. In both parental and somatic hybrid plants large quantitative variations in a mitochondrial plasmid-like DNA have been observed. Our results suggest that the cytoplasmic support for male sterility is located in the chromosomal mitochondrial DNA instead of the plasmid-like DNA.     

Ascovirus and its Evolution

Ascoviruses, iridoviruses, asfarviruses and poxviruses are all cytoplasmic DNA viruses. The evolutionary origins of cytoplasmic DNA viruses have never been fully addressed. Morphological, genetic and molecular data were used to test if all four cytoplasmic virus families (Ascoviridae, Iridoviridae, Asfarviridae, and Poxvirirdae) evolved from nuclear replicating baculoviruses and how the four virus groups are related. Molecular phylogenetic analyses using DNA polymerase predicted that cytoplasmic DNA viruses might have evolved from nuclear replicating baculoviruses, and that poxviruses and asfarviruses share a common ancestor with iridoviruses. These three cytoplasmic viruses again shared a common ancestor with ascoviruses. Morphological and genetic data predicted the same evolutionary trend as molecular data predicted. A genome sequence comparison showed that ascoviruses have more baculovirus protein homologues than do iridoviruses, which suggested that ascoviruses have evolved from baculoviruses and iridoviruses evolved from ascoviruses. Poxviruses showed genetic and morphological similarity to other cytoplamic viruses, such as ascoviruses, suggesting it has undergone reticulate evolution via hybridization, recombination and lateral gene transfer with other viruses. Within the ascovirus family, we tested if molecular phylogenetic analyses agree with biological inference; that is, ascovirus had an evolutionary trend of increasing genome size, expanding host range and widening tissue tropism for these viruses. Both molecular and biological data predicted this evolutionary trend. The phylogenetic relationship among the four species of ascovirus was predicted to be that TnAV-2 and HvAV-3 shared a common ancestor with SfAV-1 and the three virus species again shared a common ancestor with DpAV-4.     

PRMT1 Arginine Methyltransferase Accumulates in Cytoplasmic Bodies that Respond to Selective Inhibition and DNA Damage

Protein arginine methyltransferases (PRMTs) are responsible for symmetric and asymmetric methylation of arginine residues of nuclear and cytoplasmic proteins. In the nucleus, PRMTs belong to important chromatin modifying enzymes of immense functional significance that affect gene expression, splicing and DNA repair. By time-lapse microscopy we have studied the sub-cellular localization and kinetics of PRMT1 after inhibition of PRMT1 and after irradiation. Both transiently expressed and endogenous PRMT1 accumulated in cytoplasmic bodies that were located in the proximity of the cell nucleus. The shape and number of these bodies were stable in untreated cells. However, when cell nuclei were microirradiated by UV-A, the mobility of PRMT1 cytoplasmic bodies increased their, size was reduced, and they disappeared within approximately 20 min. The same response occurred after γ-irradiation of the whole cell population, but with delayed kinetics. Treatment with PRMT1 inhibitors induced disintegration of these PRMT1 cytoplasmic bodies and prevented formation of 53BP1 nuclear bodies (NBs) that play a role during DNA damage repair. The formation of 53BP1 NBs was not influenced by PRMT1 over-expression. Taken together, we show that PRMT1 concentrates in cytoplasmic bodies, which respond to DNA injury in the cell nucleus, and to treatment with various PRMT1 inhibitors.     

Ascovirus and its evolution

Ascoviruses, iridoviruses, asfarviruses and poxviruses are all cytoplasmic DNA viruses. The evolutionary origins of cytoplasmic DNA viruses have never been fully addressed. Morphological, genetic and molecular data were used to test if all four cytoplasmic virus families (Ascoviridae, Iridoviridae, Asfarviridae, and Poxvirirdae) evolved from nuclear replicating baculoviruses and how the four virus groups are related. Molecular phylogenetic analyses using DNA polymerase predicted that cytoplasmic DNA viruses might have evolved from nuclear replicating baculoviruses, and that poxviruses and asfarviruses share a common ancestor with iridoviruses. These three cytoplasmic viruses again shared a common ancestor with ascoviruses. Morphological and genetic data predicted the same evolutionary trend as molecular data predicted. A genome sequence comparison showed that ascoviruses have more baculovirus protein homologues than do iridoviruses, which suggested that ascoviruses have evolved from baculoviruses and iridoviruses evolved from ascoviruses. Poxviruses showed genetic and morphological similarity to other cytoplamic viruses, such as ascoviruses, suggesting it has undergone reticulate evolution via hybridization, recombination and lateral gene transfer with other viruses. Within the ascovirus family, we tested if molecular phylogenetic analyses agree with biological inference; that is, ascovirus had an evolutionary trend of increasing genome size, expanding host range and widening tissue tropism for these viruses. Both molecular and biological data predicted this evolutionary trend. The phylogenetic relationship among the four species of ascovirus was predicted to be that TnAV-2 and HvAV-3 shared a common ancestor with SfAV-1 and the three virus species again shared a common ancestor with DpAV-4.      

Heat shock protein 90α (Hsp90α) is phosphorylated in response to DNA damage and accumulates in repair foci

DNA damage triggers a complex signaling cascade involving a multitude of phosphorylation events. We found that the threonine 7 (Thr-7) residue of heat shock protein 90α (Hsp90α) was phosphorylated immediately after DNA damage. The phosphorylated Hsp90α then accumulated at sites of DNA double strand breaks and formed repair foci with slow kinetics, matching the repair kinetics of complex DNA damage. The phosphorylation of Hsp90α was dependent on phosphatidylinositol 3-kinase-like kinases, including the DNA-dependent protein kinase (DNA-PK) in particular. DNA-PK plays an essential role in the repair of DNA double strand breaks by nonhomologous end-joining and in the signaling of DNA damage. It is also present in the cytoplasm of the cell and has been suggested to play a role in cytoplasmic signaling pathways. Using stabilized double-stranded DNA molecules to activate DNA-PK, we showed that an active DNA-PK complex could be assembled in the cytoplasm, resulting in phosphorylation of the cytoplasmic pool of Hsp90α. In vivo, reverse phase protein array data for tumors revealed that basal levels of Thr-7-phosphorylated Hsp90α were correlated with phosphorylated histone H2AX levels. The Thr-7 phosphorylation of the ubiquitously produced and secreted Hsp90α may therefore serve as a surrogate biomarker of DNA damage. These findings shed light on the interplay between central DNA repair enzymes and an essential molecular chaperone.     

Exceptional inheritance of plastids via pollen in Nicotiana sylvestris with no detectable paternal mitochondrial DNA in the progeny

Plastids and mitochondria, the DNA‐containing cytoplasmic organelles, are maternally inherited in the majority of angiosperm species. Even in plants with strict maternal inheritance, exceptional paternal transmission of plastids has been observed. Our objective was to detect rare leakage of plastids via pollen in Nicotiana sylvestris and to determine if pollen transmission of plastids results in co‐transmission of paternal mitochondria. As father plants, we used N. sylvestris plants with transgenic, selectable plastids and wild‐type mitochondria. As mother plants, we used N. sylvestris plants with Nicotiana undulata cytoplasm, including the CMS‐92 mitochondria that cause cytoplasmic male sterility (CMS) by homeotic transformation of the stamens. We report here exceptional paternal plastid DNA in approximately 0.002% of N. sylvestris seedlings. However, we did not detect paternal mitochondrial DNA in any of the six plastid‐transmission lines, suggesting independent transmission of the cytoplasmic organelles via pollen. When we used fertile N. sylvestris as mothers, we obtained eight fertile plastid transmission lines, which did not transmit their plastids via pollen at higher frequencies than their fathers. We discuss the implications for transgene containment and plant evolutionary histories inferred from cytoplasmic phylogenies.