BACKGROUND: Malignant cell nuclei, in general, have increased amounts of heterochromatin and decreased electron densities of euchromatin, making the chromatin pattern coarser than that of benign cell nuclei. The chromatin pattern in benign and malignant cells, however, is barely explained in terms of molecular structure. In this study, the chromatin pattern of metaplastic and carcinomatous squamous cells of the uterine cervix was correlated with transcriptional activity by ultrastructural autoradiography. METHODS: Punch-biopsied tissues were cultured with 3H-uridine for 5 minutes and processed for electron microscopy. Thin sections of the tissues on nickel grids were covered with photosensitive emulsion and kept cold in a dark room for 10 to 16 weeks. After development and staining, the tissues were observed by electron microscopy. RESULTS: The nuclei of the metaplastic squamous cells consisted mostly of euchromatin. A few silver grains were observed, mainly at the periphery of the nuclei. The nuclei of the carcinomatous cells had increased amounts of heterochromatin along the nuclear membrane, and also in the euchromatin area. Silver grains were observed mainly at the boundary between the heterochromatin and euchromatin. CONCLUSION: These findings suggest that an increased amount of heterochromatin in carcinomatous cells results in an increase of the boundary area between the heterochromatin and euchromatin, an area which may be a transcriptionally active site.
Autoradiography ; Catalytic Domain ; Cell Nucleus ; Edible Grain ; Cervix Uteri ; Chromatin ; Euchromatin* ; Female ; Heterochromatin* ; Microscopy, Electron ; Molecular Structure ; Nickel ; Nuclear Envelope ; RNA, Messenger* ; Silver

Nucleolar organizer regions(NORs) are argyrophilic and have a loops of DNA that tran scribes to ribosomal RNA by RNA Polymerase I and are involved in formation of nucleolus. They are used in measuring proliferative activity of cells. Mean AgNORs count is increased or large and NORs are irregular in shape in malignant tumors. To examine the relationship of AgNORs to the survival rate of the patients with invasive colorectal adenocarcinoma, we counted mean AgNORs in 200 tumor cells and mean AgNORs#(mean AgNORs in counting AgNORs of the upper 40 nuclei after sorting AgNORs counts of 200 cell nuclei in descending order) after AgNOR staining using 45 cases of formalin-fixed, paraffin-embedded tissue surgically excised at Kang-Dong Sacred heart hospital. The survival rates were not related to age, sex, locations, differentiation, mAgNORs and mAgNORs# except Dukes'stages. There were only statistical significances in AgNORs# between high and low age group(p=0.0001), and between colon and rectum(p=0.005). But it is known that there could be different results according to staining time, fixation and preservation of tissues, counting methods in measuring AgNORs. There might be clinical usefulness of AgNOR if more cases are examined together with better tissue processing and staining methods.
Adenocarcinoma ; Cell Nucleus ; Colon ; Colorectal Neoplasms ; DNA ; Heart ; Humans ; Nucleolus Organizer Region ; RNA Polymerase I ; RNA, Ribosomal ; Survival Rate*

Linear chromatin is compacted into eukaryotic nucleus through a complex and multi-layered architecture. Consequently, chromatin conformation in a local or long-distance manner is strongly correlated with gene expression. Chromosome conformation capture (3C) technology, together with its variants like 4C/5C/Hi-C, has been well developed to study chromatin looping and whole genome structure. In this review, we introduce new technologies including chromosome capture combined with immunoprecipitation, nuclei acid-based hybridization, single cell and genome sequencing, as well as their application.
Cell Nucleus ; Chromatin/genetics* ; Chromosomes/genetics* ; Genetic Techniques ; Genome/genetics*

Three-dimensional (3D) genomics is an emerging discipline that studies the 3D spatial structure and function of genomes, focusing on the 3D spatial conformation of genome sequences in the nucleus and its biological effects on biological processes such as DNA replication, DNA recombination and gene expression regulation. The invention of chromosome conformation capture (3C) technology speeds up the research on 3D genomics and its related fields. Furthermore, the development of 3C-based technologies, such as the genome-wide chromosome conformation capture (Hi-C) and chromatin interaction analysis using paired-end tag sequencing (ChIA-PET), help scientists get insight into the 3D genomes of various species. Aims of 3D genomics are to reveal the spatial genome organization, chromosomal interaction patterns, mechanisms underlying the transcriptional regulation and formation of biological traits of microorganism, plant, animal. Additionally, the identification of key genes and signaling pathways associated with biological processes and disease via chromosome 3C technology boosts the rapid development of agricultural science, life science and medical science. This paper reviews the research progress of 3D genomics, mainly in the concept of 3D genomics, the development of chromosome 3C technologies and their applications in agricultural science, life science and medical science, specifically in the field of tumor.
Animals ; Cell Nucleus ; Chromatin/genetics* ; Chromosomes/genetics* ; Genome ; Genomics

Chromatin texture, which partly reflects nuclear organization, is evolving as an important parameter indicating cell activation or transformation. In this study, chromatin pattern was evaluated by image analysis of the electron micrographs of follicular and papillary carcinoma cells of the thyroid gland and tested for discrimination of the two neoplasms. Digital grey images were converted from the electron micrographs; nuclear images, excluding nucleolus and intranuclear cytoplasmic inclusions, were obtained by segmentation; grey levels were standardized; and grey level histograms were generated. The histograms in follicular carcinoma showed Gaussian or near-Gaussian distribution and had a single peak, whereas those in papillary carcinoma had two peaks(bimodal), one at the black zone and the other at the white zone. In papillary carcinoma. the peak in the black zone represented an increased amount of heterochromatin particles and that at the white zone represented decreased electron density of euchromatin or nuclear matrix. These results indicate that the nuclei of follicular and papillary carcinoma cells differ intheir chromatin pattern and the difference may be due to decondensed chromatin and/or matrix substances.
Carcinoma, Papillary ; Chromatin* ; Discrimination (Psychology)* ; Euchromatin ; Heterochromatin ; Inclusion Bodies ; Normal Distribution ; Nuclear Matrix ; Thyroid Gland*

Transportation between the cytoplasm and the nucleoplasm is critical for many physiological and pathophysiological processes including gene expression, signal transduction, and oncogenesis. So, the molecular mechanism for the transportation needs to be studied not only to understand cell physiological processes but also to develop new diagnostic and therapeutic targets. Recent progress in the research of the nuclear transportation (import and export) via nuclear pore complex and four important factors affecting nuclear transport (nucleoporins, Ran, karyopherins, and nuclear localization signals/nuclear export signals) will be discussed. Moreover, the clinical significance of nuclear transport and its application will be reviewed. This review will provide some critical insight for the molecular design of therapeutics which need to be targeted inside the nucleus.
Active Transport, Cell Nucleus* ; Carcinogenesis ; Cell Physiological Processes ; Cytoplasm ; Gene Expression ; Karyopherins ; Nuclear Localization Signals ; Nuclear Pore ; Nuclear Pore Complex Proteins ; Signal Transduction ; Transportation

Emerging evidence suggests that intron-detaining transcripts (IDTs) are a nucleus-detained and polyadenylated mRNA pool for cell to quickly and effectively respond to environmental stimuli and stress. However, the underlying mechanisms of detained intron (DI) splicing are still largely unknown. Here, we suggest that post-transcriptional DI splicing is paused at the Bact state, an active spliceosome but not catalytically primed, which depends on Smad Nuclear Interacting Protein 1 (SNIP1) and RNPS1 (a serine-rich RNA binding protein) interaction. RNPS1 and Bact components preferentially dock at DIs and the RNPS1 docking is sufficient to trigger spliceosome pausing. Haploinsufficiency of Snip1 attenuates neurodegeneration and globally rescues IDT accumulation caused by a previously reported mutant U2 snRNA, a basal spliceosomal component. Snip1 conditional knockout in the cerebellum decreases DI splicing efficiency and causes neurodegeneration. Therefore, we suggest that SNIP1 and RNPS1 form a molecular brake to promote spliceosome pausing, and that its misregulation contributes to neurodegeneration.
Spliceosomes/metabolism* ; Introns/genetics* ; RNA Splicing ; RNA, Messenger/genetics* ; Cell Nucleus/metabolism*

AIMTo simultaneously determine the localization of histones and protamines within human sperm nuclei.

METHODSImmunofluorescence of the core histones and protamines and fluorescence in situ hybridization of the telomere region of chromosome 16 was assessed in decondensed human sperm nuclei.

RESULTSImmunofluorescent localization of histones, protamine 1 (PRM1) and protamine 2 (PRM2) along with fluorescence in situ hybridization localization of chromosome 16 telomeric sequences revealed a discrete distribution in sperm nuclei. Histones localized to the posterior ring region (i.e. the sperm nuclear annulus), whereas PRM1 and PRM2 appeared to be dispersed throughout the entire nucleus.

CONCLUSIONThe co-localization of the human core sperm histones with the telomeric regions of chromosome 16 is consistent with the reorganization of specific non-protamine regions into a less compacted state.

Cell Nucleus ; metabolism ; Chromosomes, Human, Pair 16 ; metabolism ; Histones ; metabolism ; Humans ; Male ; Protamines ; metabolism ; Spermatozoa ; metabolism ; Telomere ; metabolism

Bidirectional trafficking of macromolecules between the cytoplasm and the nucleus is mediated by the nuclear pore complexes (NPCs) embedded in the nuclear envelope (NE) of eukaryotic cell. The NPC functions as the sole pathway to allow for the passive diffusion of small molecules and the facilitated translocation of larger molecules. Evidence shows that these two transport modes and the conformation of NPC can be regulated by calcium stored in the lumen of nuclear envelope and endoplasmic reticulum. However, the mechanism of calcium regulation remains poorly understood. In this review, we integrate data on the observations of calciumregulated structure and function of the NPC over the past years. Furthermore, we highlight challenges in the measurements of dynamic conformational changes and transient transport kinetics in the NPC. Finally, an innovative imaging approach, single-molecule superresolution fluorescence microscopy, is introduced and expected to provide more insights into the mechanism of calcium-regulated nucleocytoplasmic transport.
Active Transport, Cell Nucleus ; physiology ; Animals ; Calcium ; metabolism ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Diffusion ; Endoplasmic Reticulum ; metabolism ; Eukaryotic Cells ; metabolism ; Humans ; Ion Transport ; physiology ; Microscopy, Fluorescence ; Molecular Conformation ; Nuclear Pore ; chemistry ; metabolism ; Nuclear Pore Complex Proteins ; chemistry ; metabolism ; Oocytes ; cytology ; metabolism ; Signal Transduction ; Xenopus laevis

To study the impact of the enterovirus 71(EV71) on the nuclear transport mechanism,The pGFP-NLS vector with nuclear location signal(NLS) was constructed, RD cells transfected by the pGFP-NLS vector were inoculated with the EV71 or cotransfected by EV71-2A vector. The results showed that GFP protein with NLS was expressed in the cytoplasm due to the inhibition of nuclear transport. In order to further study the mechanism of the EV71 to prevent nuclear transport,Nup62 was detected by Western blotting after RD cells were infected with EV71 or transfected by EV71-2A vector. The results showed that decreased expression of Nup62 could be detected after infection with EV71 and transfection by EV71-2A vector. This study demonstrates that the cleavage of Nup62 by EV71 2A protease may be the mechanism of nuclear transport inhibition.
Active Transport, Cell Nucleus ; Cell Line, Tumor ; Cell Nucleus ; metabolism ; Enterovirus A, Human ; enzymology ; genetics ; metabolism ; Enterovirus Infections ; virology ; Gene Expression Regulation, Viral ; Genetic Vectors ; Green Fluorescent Proteins ; metabolism ; Humans ; Membrane Glycoproteins ; metabolism ; Nuclear Localization Signals ; metabolism ; Nuclear Pore Complex Proteins ; metabolism ; Peptide Hydrolases ; metabolism ; Recombinant Fusion Proteins ; metabolism ; Transfection