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Search Results: 1 - 10 of 2053 matches for " Zhonghe Zhai "
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Relation between nuclear envelope and nuclear lamina in nuclear assemblyin vitro
Shutao Cai,Zhonghe Zhai
Science China Life Sciences , 1997, DOI: 10.1007/BF02882687
Abstract: Xenopus laevis egg extracts cell-free nuclear assembly system was used as an experimental model to study the process of nuclear lamina assembly in nuclear reconstitutionin vitro. The experimental results showed that lamin was involved in the nuclear assemblyin vitro. The assembly of nuclear lamina was preceded by the assembly of nuclear matrix, and probably, inner nuclear matrix assembly provided the basis for nuclear lamina assembly. Inhibition of normal assembly of nuclear Iknina, by preincubating egg extracts cell-free system with anti-lamin antibodies, resulted in abnormal assembly of nuclear envelope, suggesting that nuclear envelope assembly is closely associated with nuclear lamina assembly.
Relation between nuclear envelope and nuclear lamina in nuclear assembly in vitro

CAI Shutao,ZHAI Zhonghe,

中国科学C辑(英文版) , 1997,
Abstract: Xenopus laevis egg extracts cell-free nuclear assembly system was used as an experimental model to study the process of nuclear lamina assembly in nuclear reconstitutionin vitro. The experimental results showed that lamin was involved in the nuclear assemblyin vitro. The assembly of nuclear lamina was preceded by the assembly of nuclear matrix, and probably, inner nuclear matrix assembly provided the basis for nuclear lamina assembly. Inhibition of normal assembly of nuclear Iknina, by preincubating egg extracts cell-free system with anti-lamin antibodies, resulted in abnormal assembly of nuclear envelope, suggesting that nuclear envelope assembly is closely associated with nuclear lamina assembly. Project supported by the National Natural Science Foundation of China.
Nuclear reassemblyin vitro is independent of nucleosome/chromatin assembly
Zhengfan Jiang,Bo Zhang,Zhonghe Zhai
Science China Life Sciences , 1998, DOI: 10.1007/BF02882889
Abstract: It was show11 that nuclear reassembly was induced by small pieces of DNA fragments in cell-free extracts ofXenopus. In an attempt to learn the relationship between the nuclear reassembly and nucleosome/chromatin assembly, limited amounts of CM-Cellulose are used to eliminate the capacity of the egg extract S-150 to assemble chromatin. while the forming of nucleosomes is checked with DNA supercoiling by plasmid DNA pBR322 incubated in the extract, and further analysed by micrococcal nuclease digestion. This depleted extract is then used to induce nuclear reassembly around demembraned sperms with membrane vesicles. It is found that CM-Cellulose depletes histones H2A and H2B efficiently and blocks the assembly of nucleosomes, the demembraned sperms are yet reconstituted into nuclei in the treated S-150, although the chromatin in reassembled nuclei does not produce protected DNA fragments when digested with micrococcal nuclease. It suggests that in the cell-free system ofXenopus, DNA can be formed into nuclei without assembly of nucleosomes or chromatin.
Nuclear reconstitution of demembranatedOrychophragmus violaceus sperm inXenopus laevis egg extracts
Ping Lu,Min Ren,Zhonghe Zhai
Science China Life Sciences , 2002, DOI: 10.1007/BF02879750
Abstract: The cell-free extracts from animalXenopus laevis egg could induce chromatin decondensation and pronuclear formation from demembranated plant (Orychophragmus violaceu) sperm. The demembranatedOrychophragmus violaceus sperm began to swell in 30 min incubation, and then were gradually decondensed. The reassembly of nuclear envelope in the reconstituted nuclei had been visualized by means of electron microscopy and fluorescent microscopy. Membrane vesicles fused to form the double envelope around the periphery of the decondensed chromatin. The morphology of the newly formed nucleus, with a double membrane, was similar to those nuclei after fertilization. Transmission electron microscope micrograph of the whole mount prepared nuclear matrix-lamina showed the reconstituted nucleus to be filled with a dense network.
Nicotiana ovule extracts induce nuclear reconstitution of demembranated Xenopus sperm in cell-free system
Ping Lu,Min Ren,Zhonghe Zhai
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9072
Abstract: Nicotiana tabaccum ovule extracts induced nuclear reconstitution of demembranated Xenopus leavis sperm in a cell-free system. Demembranated Xenopus sperm began to swell after 15 min of incubation with Nicotiana ovule extracts. Accompanying the process of incubation, Xenopus sperm decondensed and their shapes changed gradually from long and ellipse to round. The completely decondensed chromatin was surrounded with membrane structure, which was a mixture envelope of a double membrane and a single membrane. Nucleosome assembly was verified by means of micrococcal nuclease digestion to reconstituted nuclei and DNA electrophoresis. Nicotiana ovule extracts supplied one more experimental model and system. The new system could promote powerfully the research on mechanisms of cell division and cell cycle regulation.
Coil-1 of rod domain of NF-L is essential for its assemblyin vivo
Xiangjun Tong,Zhonghe Zhai,Jianguo Chen
Science China Life Sciences , 1999, DOI: 10.1007/BF02881767
Abstract: Neurofilaments take highly ordered structures composed of parallel mays of 10 nm filaments linked to each other with frequent cross-bridge. It is composed of three components named NF-L, NF-M and NF-H. NF-L is able to form filamentous network alone in Sf9 cells, while M could not. To identify which domain is essential for the assembly of NF-L, two chimera proteins named ML and MML were constructed: ML was composed of the head domain of NF-M and other domains of NF-L; MML was composed of the head and Coil-1 domains of NF-M and Coil-2 and tail domains of NF-L. ML was not only able to form filaments in Sf9 cells, but also co-assemble with NF-M into parallel filamentous bundles. MML could not assemble into filaments. Thus the Coil-1 domain of NF-L was essential for its assembly.
50 ku keratin-like protein and β-microtublin coexist in higher plant cells
Danying Chen,Cheng Yang,Zhonghe Zhai
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02884666
Abstract: IF-like proteins have been obtained from suspension cells ofNicotiana tabacum by selective extraction. Western blot analysis shows that the major components of IF-like proteins are 6 keratin-like proteins of 64, 58, 55, 54, 50 and 45 ku. Specially the 50 ku protein also reacts with polyantibody against microtublin. Two-dimensional gel electrophoresis shows that the 50 ku protein is composed of two different proteins and their amino acid sequences have been determined. Part of the sequence of one protein is identical to that of β-microtublin and the other protein’s sequence has no significant homologue, which should be a new sequence-unknown protein. These results suggest that 50 ku keratin-like protein and β-microtublin coexist in higher plant cells, and that may lead to the phenomenon of co-distribution of IF and microtuble in plant cells.
Nuclear reassembly in vitro is independent of nucleosome/chromatin assembly

JIANG Zhengfan,ZHANG Bo,ZHAI Zhonghe,

中国科学C辑(英文版) , 1998,
Abstract: It was show11 that nuclear reassembly was induced by small pieces of DNA fragments in cell-free extracts ofXenopus. In an attempt to learn the relationship between the nuclear reassembly and nucleosome/chromatin assembly, limited amounts of CM-Cellulose are used to eliminate the capacity of the egg extract S-150 to assemble chromatin. while the forming of nucleosomes is checked with DNA supercoiling by plasmid DNA pBR322 incubated in the extract, and further analysed by micrococcal nuclease digestion. This depleted extract is then used to induce nuclear reassembly around demembraned sperms with membrane vesicles. It is found that CM-Cellulose depletes histones H2A and H2B efficiently and blocks the assembly of nucleosomes, the demembraned sperms are yet reconstituted into nuclei in the treated S-150, although the chromatin in reassembled nuclei does not produce protected DNA fragments when digested with micrococcal nuclease. It suggests that in the cell-free system ofXenopus, DNA can be formed into nuclei without assembly of nucleosomes or chromatin. Projrrt supported by the National Natural Science Foundation of China (Grant No. 39730240)
Nuclear reconstitution of demembranatedOrychophragmus violaceus sperm inXenopus laevis egg extracts

Ping Lu,Min Ren,Zhonghe Zhai,

中国科学C辑(英文版) , 2002,
Abstract: The cell-free extracts from animalXenopus laevis egg could induce chromatin decondensation and pronuclear formation from demembranated plant (Orychophragmus violaceu) sperm. The demembranatedOrychophragmus violaceus sperm began to swell in 30 min incubation, and then were gradually decondensed. The reassembly of nuclear envelope in the reconstituted nuclei had been visualized by means of electron microscopy and fluorescent microscopy. Membrane vesicles fused to form the double envelope around the periphery of the decondensed chromatin. The morphology of the newly formed nucleus, with a double membrane, was similar to those nuclei after fertilization. Transmission electron microscope micrograph of the whole mount prepared nuclear matrix-lamina showed the reconstituted nucleus to be filled with a dense network.
Coil-1 of rod domain of NF-L is essential for its assembly in vivo

TONG Xiangjun,ZHAI Zhonghe,CHEN Jianguo,

中国科学C辑(英文版) , 1999,
Abstract: Neurofilaments take highly ordered structures composed of parallel mays of 10 nm filaments linked to each other with frequent cross-bridge. It is composed of three components named NF-L, NF-M and NF-H. NF-L is able to form filamentous network alone in Sf9 cells, while M could not. To identify which domain is essential for the assembly of NF-L, two chimera proteins named ML and MML were constructed: ML was composed of the head domain of NF-M and other domains of NF-L; MML was composed of the head and Coil-1 domains of NF-M and Coil-2 and tail domains of NF-L. ML was not only able to form filaments in Sf9 cells, but also co-assemble with NF-M into parallel filamentous bundles. MML could not assemble into filaments. Thus the Coil-1 domain of NF-L was essential for its assembly. Project supported by the National Grant for Outstanding Young Scientists.
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