In this study, freeze - fractured specimens of Allium cepa root tip meristems were examined under the scanning electron microscope (SEM). This technique permitted the visualization of the outer membrane of the nuclear...In this study, freeze - fractured specimens of Allium cepa root tip meristems were examined under the scanning electron microscope (SEM). This technique permitted the visualization of the outer membrane of the nuclear envelope with nuclear pore complexes and polyribosomes. Some of the cell nuclei prepared with this procedure had fissures of various widths on their nuclear envelopes through which the nuclear lamina-like filaments (LLF) underneath the nucleoplasmic side of the envelopes were clearly visible. The diameters of these filaments varied between 25 and 125 nm. Many of the LLFs showed granular thickenings at places, and were attached to the inner surface of nuclear envelope in some regions. Similar LLFs were also seen at the peripheries of the freeze -fractured faces of nuclei. Meanwhile,the spatial relation between the nuclear matrix filaments (NMF) and other nuclear structures (nucleoli, chromatin and peripheral lamina - like filaments) was revealed in these fractured preparations. In addition, the methods and techniques in studying the nuclear lamina morphology and the roles played by NMFs in activities of various nuclear structures were discussed in brief.展开更多
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 reconstitution in vitro. The experimental results showed that ...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 reconstitution in vitro. The experimental results showed that lamin was involved in the nuclear assembly in 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 lamina, 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.展开更多
The fine structure of the nuclear lamina （NL） in sperm cells of \%Ginkgo biloba\% was visualised using high resolution low\|voltage scanning electron microscopy （LVSEM）. It was shown that the nuclear lamina was co...The fine structure of the nuclear lamina （NL） in sperm cells of \%Ginkgo biloba\% was visualised using high resolution low\|voltage scanning electron microscopy （LVSEM）. It was shown that the nuclear lamina was composed of 10 nm filaments which formed a fine network. Lamins were purified from cultured carrot suspension cells and assembled \%in vitro.\% Long 8\12 nm diameter filaments were seen and sometimes subfilaments could be distinguished. Western blot of filament preparations showed that these contained the 66 and 84 ku lamins. These data demonstrate that plant lamins are capable of assembling into filaments \%in vitro.\%展开更多
目的:近年来,肿瘤微环境在恶性肿瘤中的作用受到广泛关注,但胃癌与肿瘤微环境的关系尚不完全清楚。本研究旨在探讨核纤层蛋白B2(nuclear lamina protein B2,LMNB2)在胃癌中的表达及其与肿瘤微环境的关系。方法:通过癌症基因组图谱(The C...目的:近年来,肿瘤微环境在恶性肿瘤中的作用受到广泛关注,但胃癌与肿瘤微环境的关系尚不完全清楚。本研究旨在探讨核纤层蛋白B2(nuclear lamina protein B2,LMNB2)在胃癌中的表达及其与肿瘤微环境的关系。方法:通过癌症基因组图谱(The Cancer Genome Atlas,TCGA)分析LMNB2基因在胃癌组织及正常胃黏膜组织中的表达差异。收集92例手术切除的胃癌及相应癌旁5 cm以上的胃黏膜组织标本,采用免疫组织化学方法检测其中LMNB2的表达情况,并分析LMNB2的表达水平与胃癌患者临床病理特征之间的关系。运用Kaplan-Meier生存曲线分析LMNB2表达水平与胃癌生存预后的关系。通过R软件和TISIDB(an integrated repository portal for tumor-immune system interactions)数据库对目标基因进行基因本体(Gene Ontology,GO)和京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析,并分析其与肿瘤免疫特征之间的相关性。基于CIBERSORT(Cell-type Identification by Estimating Relative Subsets of RNA Transcripts)算法进行LMNB2表达与免疫细胞浸润水平相关性预测,评价LMNB2表达水平对肿瘤微环境的影响。结果:TCGA数据库分析显示:胃癌组织中的LMNB2基因表达水平较正常胃黏膜组织明显增高(P<0.001)。LMNB2的表达水平与胃癌患者的淋巴结转移、肿瘤浸润深度、TNM分期及远处转移均有关(均P<0.05),与患者性别、年龄、肿瘤大小等无关(均P>0.05)。Kaplan-Meier生存曲线显示:LMNB2表达阳性患者总体生存时间较LMNB2阴性患者显著缩短(P<0.001)。LMNB2差异基因主要集中富集在体液免疫反应的调节等过程。此外LMNB2差异基因的表达与M0型巨噬细胞、CD4^(+)记忆T细胞等免疫细胞浸润水平均呈正相关(均P<0.05)。结论:LMNB2在胃癌组织中呈高表达,与患者预后生存不良相关,LMNB2与胃癌预后和免疫微环境高度相关,有望成为胃癌免疫治疗的潜在生物标志物。展开更多
Herpesviruses assemble and fill their capsids in the infected cell nucleus, and must then move this enormous macromolecular assembly across the nuclear membrane and into the cytoplasm. Doing so is a complex, multi-ste...Herpesviruses assemble and fill their capsids in the infected cell nucleus, and must then move this enormous macromolecular assembly across the nuclear membrane and into the cytoplasm. Doing so is a complex, multi-step process that involves envelopment of the capsid at the inner nuclear membrane and de-envelopment by fusion with the outer nuclear membrane. This process is orchestrated by viral proteins, but requires the modification of cellular structures and mechanisms including the nuclear lamina. In this review I summarize recent research on the mechanism of nuclear envelopment and the viral and cellular systems involved in its execution.展开更多
The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezo...The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezoa Giardia lamblia already possessed nuclear matrix within its two nuclei. The finest fibrils of the nuclear matrix of Giardia lamblia were measured to be about 11 to 13 nm in thickness. However, the nuclear lamina and nucleolus have never been observed. These results seem to suggest that nuclear matrix is an indispensable intranuclear structural component even in the primitive nucleus.展开更多
After lamins A, B and C were isolated and purified from rat liver, their assembly properties were examined by electron microscopy and scanning tunneling microscopy using negative staining and the glycerol coating meth...After lamins A, B and C were isolated and purified from rat liver, their assembly properties were examined by electron microscopy and scanning tunneling microscopy using negative staining and the glycerol coating method,respectively By varying the assembly time or the ionic conditions under which polymerization takes place, we have observed different stages of lamin assembly, which may provide clues on the structure of the 10 nm lamin filaments. At the first level of structural organization, two lamin polypeptides associate laterally into dimers with the two domains being parallel and in register. At the second level of structural organization, two dimers associate in a half-staggered and atiparallel fashion to form a tetramer 75 nm in length. At the third level of structural organization, 4-10 lamin tetramers associate laterally in register to form 75 nm long 10nm filaments, which in turn combine head to head into long, fully assembled lamin filaments.The assembled lamin filaments are nonpolar.展开更多
文摘In this study, freeze - fractured specimens of Allium cepa root tip meristems were examined under the scanning electron microscope (SEM). This technique permitted the visualization of the outer membrane of the nuclear envelope with nuclear pore complexes and polyribosomes. Some of the cell nuclei prepared with this procedure had fissures of various widths on their nuclear envelopes through which the nuclear lamina-like filaments (LLF) underneath the nucleoplasmic side of the envelopes were clearly visible. The diameters of these filaments varied between 25 and 125 nm. Many of the LLFs showed granular thickenings at places, and were attached to the inner surface of nuclear envelope in some regions. Similar LLFs were also seen at the peripheries of the freeze -fractured faces of nuclei. Meanwhile,the spatial relation between the nuclear matrix filaments (NMF) and other nuclear structures (nucleoli, chromatin and peripheral lamina - like filaments) was revealed in these fractured preparations. In addition, the methods and techniques in studying the nuclear lamina morphology and the roles played by NMFs in activities of various nuclear structures were discussed in brief.
基金Project supported by the National Natural Science Foundation of China.
文摘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 reconstitution in vitro. The experimental results showed that lamin was involved in the nuclear assembly in 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 lamina, 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.
文摘The fine structure of the nuclear lamina （NL） in sperm cells of \%Ginkgo biloba\% was visualised using high resolution low\|voltage scanning electron microscopy （LVSEM）. It was shown that the nuclear lamina was composed of 10 nm filaments which formed a fine network. Lamins were purified from cultured carrot suspension cells and assembled \%in vitro.\% Long 8\12 nm diameter filaments were seen and sometimes subfilaments could be distinguished. Western blot of filament preparations showed that these contained the 66 and 84 ku lamins. These data demonstrate that plant lamins are capable of assembling into filaments \%in vitro.\%
文摘目的:近年来,肿瘤微环境在恶性肿瘤中的作用受到广泛关注,但胃癌与肿瘤微环境的关系尚不完全清楚。本研究旨在探讨核纤层蛋白B2(nuclear lamina protein B2,LMNB2)在胃癌中的表达及其与肿瘤微环境的关系。方法:通过癌症基因组图谱(The Cancer Genome Atlas,TCGA)分析LMNB2基因在胃癌组织及正常胃黏膜组织中的表达差异。收集92例手术切除的胃癌及相应癌旁5 cm以上的胃黏膜组织标本,采用免疫组织化学方法检测其中LMNB2的表达情况,并分析LMNB2的表达水平与胃癌患者临床病理特征之间的关系。运用Kaplan-Meier生存曲线分析LMNB2表达水平与胃癌生存预后的关系。通过R软件和TISIDB(an integrated repository portal for tumor-immune system interactions)数据库对目标基因进行基因本体(Gene Ontology,GO)和京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析,并分析其与肿瘤免疫特征之间的相关性。基于CIBERSORT(Cell-type Identification by Estimating Relative Subsets of RNA Transcripts)算法进行LMNB2表达与免疫细胞浸润水平相关性预测,评价LMNB2表达水平对肿瘤微环境的影响。结果:TCGA数据库分析显示:胃癌组织中的LMNB2基因表达水平较正常胃黏膜组织明显增高(P<0.001)。LMNB2的表达水平与胃癌患者的淋巴结转移、肿瘤浸润深度、TNM分期及远处转移均有关(均P<0.05),与患者性别、年龄、肿瘤大小等无关(均P>0.05)。Kaplan-Meier生存曲线显示:LMNB2表达阳性患者总体生存时间较LMNB2阴性患者显著缩短(P<0.001)。LMNB2差异基因主要集中富集在体液免疫反应的调节等过程。此外LMNB2差异基因的表达与M0型巨噬细胞、CD4^(+)记忆T细胞等免疫细胞浸润水平均呈正相关(均P<0.05)。结论:LMNB2在胃癌组织中呈高表达,与患者预后生存不良相关,LMNB2与胃癌预后和免疫微环境高度相关,有望成为胃癌免疫治疗的潜在生物标志物。
基金supported by US Public health Service award AI 41478
文摘Herpesviruses assemble and fill their capsids in the infected cell nucleus, and must then move this enormous macromolecular assembly across the nuclear membrane and into the cytoplasm. Doing so is a complex, multi-step process that involves envelopment of the capsid at the inner nuclear membrane and de-envelopment by fusion with the outer nuclear membrane. This process is orchestrated by viral proteins, but requires the modification of cellular structures and mechanisms including the nuclear lamina. In this review I summarize recent research on the mechanism of nuclear envelopment and the viral and cellular systems involved in its execution.
文摘The nuclear matrix of diplomonad Giardia lamblia was detected for the first time with DGD embedmentsectioning- embedment free electron microscopy after a series of specific extractions. The result showed that archaezoa Giardia lamblia already possessed nuclear matrix within its two nuclei. The finest fibrils of the nuclear matrix of Giardia lamblia were measured to be about 11 to 13 nm in thickness. However, the nuclear lamina and nucleolus have never been observed. These results seem to suggest that nuclear matrix is an indispensable intranuclear structural component even in the primitive nucleus.
文摘After lamins A, B and C were isolated and purified from rat liver, their assembly properties were examined by electron microscopy and scanning tunneling microscopy using negative staining and the glycerol coating method,respectively By varying the assembly time or the ionic conditions under which polymerization takes place, we have observed different stages of lamin assembly, which may provide clues on the structure of the 10 nm lamin filaments. At the first level of structural organization, two lamin polypeptides associate laterally into dimers with the two domains being parallel and in register. At the second level of structural organization, two dimers associate in a half-staggered and atiparallel fashion to form a tetramer 75 nm in length. At the third level of structural organization, 4-10 lamin tetramers associate laterally in register to form 75 nm long 10nm filaments, which in turn combine head to head into long, fully assembled lamin filaments.The assembled lamin filaments are nonpolar.
