Impaired Nucleoporins Are Present in Sporadic Amyotrophic Lateral Sclerosis Motor Neurons that Exhibit Mislocalization of the 43-kDa TAR DNA-Binding Protein

BACKGROUND AND PURPOSE: Disruption of nucleoporins has been reported in the motor neurons of patients with sporadic amyotrophic lateral sclerosis (sALS). However, the precise changes in the morphology of nucleoporins associated with the pathology of the 43-kDa TAR DNA-binding protein (TDP-43) in the disease process remain unknown. We investigated the expression of nucleoporins that constitute the nuclear pore complex (NPC) in spinal motor neurons that exhibit sALS in relation to TDP-43 pathology, which is a reliable neuropathological hallmark of sALS. METHODS: Paraffin-embedded sections of the lumbar spinal cord were obtained for immunofluorescence analysis from seven control subjects and six sALS patients. Anti-TDP-43 antibody, anti-nucleoporin p62 (NUP62) antibody, and anti-karyopherin beta 1 (KPNB1) antibody were applied as primary antibodies, and then visualized using appropriate secondary antibodies. The sections were then examined under a fluorescence microscope. RESULTS: NUP62 and KPNB1 immunoreactivity appeared as a smooth round rim bordering the nuclear margin in normal spinal motor neurons that exhibited nuclear TDP-43 immunoreactivity. sALS spinal motor neurons with apparent TDP-43 mislocalization demonstrated irregular, disrupted nuclear staining for NUP62 or KPNB1. Some atrophic sALS spinal motor neurons with TDP-43 mislocalization presented no NUP62 immunoreactivity. CONCLUSIONS: Our findings suggest a close relationship between NPC alterations and TDP-43 pathology in the degenerative process of the motor neurons of sALS patients.

Nucleoporin and tumor / 国际肿瘤学杂志

In eukaryotes,the cell(s) material exchange has long existed in its proliferation and apoptosis,while the exchange of nucleus and cytoplasm only through the shuttle movement of the nuclear pore complex (NPC). NPC in the nuclear membrane,achieves the protein,RNA and other substances's transport task through the shuttle movement between nucleus and cytoplasm of eukaryotes.Specific nuclear pore proteins regulate specific transport path,and because of this,the transport and regulation through the NPC is highly selective and coordination,so the NPC play an important role in gene expression,cell signaling networks and maintain the environment.Some of them will change the structure properties of membrane,affecting mitosis,and some can be combined with the kinase leading to abnormal biochemical reactions,or combined with other biological factors in angiogenesis,cell migration or apoptosis of cells leading to abnormal changes,and leading to tumorigenesis.

Dinámica del cmpplejo del poro nuclarr / Dinamicsof nucleear pore compexx

El complejo del poro nuclear (CPN) es un conjunto supra-molecular compuesto de múltiples copias de 30 familias de proteínas diferentes, siendo 456 nucleoporinas (Nups) en total que atraviesan la envoltura nuclear de todos los organismos pertenecientes al dominio Eukaria. El CPN es la compuerta del núcleo por lo tanto, todas las macromoléculas deben atravesarla para transitar del núcleo al citoplasma y viceversa. Durante los últimos años, se han propuesto varios modelos para explicar la regulación y el transporte de macromoléculas a través del CPN. En este escrito se describe la estructura, los mecanismos y procesos involucrados durante el transporte a través del CPN, y cómo estos procesos son regulados por interacciones macromoleculares altamente dinámicas.

The nuclear pore complex (NPC) is a large supramolecular assemble made up of multiple copies of about 30 different families proteins, so in total 456 nucleoporines (Nups) span the nuclear envelope of all Eukariotic organisms. The NPC is considered the gate through which all macromolecules must pass in order to achieve nucleo-cytoplasmic transport. The aim of this review is to describe the structure, mechanisms and processes involved during the transportation of molecules and how of these processes are regulated by highly dynamic macromolecular interactions with molecules of the NPC which have been described during the past years.

The Nucleocytoplasmic Transport of Viral Proteins / 中国病毒学·英文版

Molecules can enter the nucleus by passive diffusion or active transport mechanisms, depending on their size. Small molecules up to size of 50-60 kDa or less than 10 nm in diameter can diffuse passively through the nuclear pore complex (NPC), while most proteins are transported by energy driven transport mechanisms. Active transport of viral proteins is mediated by nuclear localization signals (NLS), which were first identified in Simian Virus 40 large T antigen and had subsequently been identified in a large number of viral proteins. Usually they contain short stretches of lysine or arginine residues. These signals are recognized by the importin super-family (importin α and β) proteins that mediate the transport across the nuclear envelope through Ran-GTP. In contrast, only one class of the leucine-rich nuclear export signal (NES) on viral proteins is known at present. Chromosome region maintenance 1 (CRM1) protein mediates nuclear export of hundreds of viral proteins through the recognition of the leucine-rich NES.

Through The Door to The Nucleus:Progress on Nuclear Translocation Mechanism / 生物化学与生物物理进展

DNA replication and RNA biogenesis happen in the cell nucleus,while protein synthesis occurs in the cytoplasm. Integration of these activities depends on function proteins′ selective transport between the two sub-dimensions. It is a signal mediated process, which needs energy and the participation of soluble factors. By introduction of progress on function protein regulated nuclear translocation, its potential medical application has been explored. With deeper investigation in this field, it will significantly promote the design of anti-virus and gene vector therapy.

Sec13 induces genomic instability in U2OS cells

Sec13p has been known as an endoplasmic reticulum-Golgi transport protein. Recently, it has also been shown to be required for the formation of septation in the fission yeast Schizosaccharomyces pombe. In the present study, we focused on the role of a human homolog of Saccharomyces cerevisiae SEC13, Sec13 protein during mitosis in U2OS cells. We found that the expression of Sec13 was constant throughout the cell cycle, and localized to the kinetochores at metaphase during mitosis. By using green fluorescent protein technology, we observed that Sec13 is required for evasion of mitotic arrest in response to spindle damage, leading to G1-like phase and apoptotic cell death. In addition, cells expressing exogenous Sec13 showed giant nuclei compared to endogenous ones in the absence of nocodazole. These results demonstrate that Sec13 is involved in the regulation of the metaphase/anaphase transition and may be functionally associated with mitotic machinery to maintain genomic stability during mitosis.

Changes in nuclear calcium content and permeability of nuclear pore complex in rat myocardium during ischemia reperfusion injury / 中国病理生理杂志

AIM: To investigate the changes in nuclear calcium content and permeability of nuclear pore complex in rat myocardium during ischemia reperfusion injury.METHODS: The rat model of myocardial ischemia reperfusion injury was established.Myocardial nuclei were purified using sucrose density gradient centrifugation.The nuclear calcium content was measured by atomic absorption spectrophotometer.The permeability of nuclear pore complex was assessed through measuring the amount of calmodulin conjugated Alexa Fluo~(TM) 488 as fluorescent probes transported across nuclear membrane with spectrofluorometer.RESULTS: The nuclear calcium content at 15,30,60,120 and 180 min reperfusion following 30 min sustained ischemia increased 1.31-,1.55-,1.73-,1.94-and 2.14-fold,respectively,as compared with sham-operation group.The permeability of nuclear pore complex at 15 min reperfusion following 30 min sustained ischemia showed no difference from sham-operation group,but it only increased 1.31-,1.38-,1.40-,and 1.48-fold at 30,60,120 and 180 min reperfusion following 30 min sustained ischemia compared with sham-operation group.CONCLUSION: The nuclear calcium content during myocardial ischemia reperfusion injury increases earlier than the permeability of nuclear pore complex does.The increase in the permeability of nuclear pore complex may result in adaptive regulatory effects on nuclear calcium overload to a certain extent during myocardial ischemia reperfusion injury.

MORpHOLOGY OF OOCYTE IN THE CHINESE WOMAN / 解剖学报

Fifty oocytes were studied with light microscope and electron microscope. The shape of oocyte is round, about 50—100?m in diameter. The nucleus is large and spheroidal in shape. The diameter of the nucleus is 15—20?m. All the oocytes are surrounded by zona pellucida and follicular cells. Call-Exner bodies are seen between these follicular cells. A great number of microvilli are present on the surface of oocytes. The paired membranes of nucleus envelope is clearly seen. There are a lot of nuclear pores on nuclear envelope, about 4,000/mm~2. The nuclear pore complex is disinct. The cytoplasm of oocyte abounds with organelles which are distributed regularly. The cristae of mitochondria are short and scarety. The mitochondrial matrix becomes very dense. The cavities of endoplasmic reticulum are distended. Well developed Golgi complex are usually found at the periphery of oocytes. Annulate lamellae consist of parallel flat sacs with a length of 1.5—2.0?m. There are structures like nuclear pores on the flat sac. Some bunchs of fibrous material in the cytoplasm of oocytes are called yolk plates Each yolk plate consists of a regular alternating dark and light bands with a periodicity of 20nm. Cortical granules are round with a diameter of 0.2—0.4?m. They are wrapped up in a membrane. Their electron density is high.

ULTRASTRUCTURAL STUDY ON THE PROCESS OF NUCLEAR RECONSTITUTION IN A CELL-FREE SYSTEM FROM XENOPUS EGGS / 解剖学报

Nuclear reconstitution around Lambda DNA in a cell-free system from Xenopus eggs involves distinct steps at ultrastructural level. First, Lambda DNA polymers were induced to form chromatin-like structures with the proteins in egg extracts. Then, along with membrane vesicles and nuclear pore components attached to them to assemble double nuclear membranes, these chromatin-like structures underwent variations from condensation to decondensation, simultaneously. It is different from the nuclear reconstitution induced by chromatin in that, while membrane vesicles were attaching to the chromatin-like structures to fuse each other, the assembly of nuclear pore complexes occurred practically.