On the history of nuclear matrix manifestation

The nonchromatin proteinous residue of the cell nucleus was revealed in our laboratory as early as in 1948 and then identified by light and electron microscopy as residual nucleoli,intranuclear network and nuclear envelope before 1960,This structure termed afterwards as “nuclear residue“,“nuclear skeleton“,“nuclear cage“,“nuclear carcass“etc.,was much later(in 1974) isolated,studied and entitled as “nuclear matrix“ by Berezney and Coffey,to whom the discovery of this residual structure is often wronly ascribed.The real history of nuclear matrix manifestation is reported in this paper.     

Specificity of antinuclear autoantibodies in diseases with systemic destruction of connective tissue]

By using the fluorescent antibody technique several patterns of antinuclear antibodies (ANA) were detected in the systemic connective tissue diseases, as well as in some other diseases and in healthy donors, depending on the character of nuclear fluorescence. Homogeneous nuclear fluorescence, homogeneous fluorescence free of nucleaolar fluorescence, ring-shaped fluorescence, lumpy fluorescence, selective nuclealar fluorescence, nuclear fluorescence in the form of long fine plexiform bands associated with fluorescence in the nuclear membrane region. The latter ANA pattern was found only in several forms of lupus erythematosus, and this fluorescence was different from the previously reported "reticular" and "filamentous" patterns.     

Melting fine structure of filamentous fungus nuclear DNA.

Melting fine structure of the nuclear DNA isolated from the filamentous fungus Fusarium graminearum Schwabe is presented. Optical melting profiles of nuclear DNA were analyzed by using a combination of curve fitting and derivative techniques. The "melting components" were obtained from the derivative curve by a simple decomposition technique. Differential optical melting curves of unsheared nuclear DNA indicate the presence of 15 "melting components" in filamentous fungus nuclear genome. It should be emphasized that the "melting components" observed here are different from the "thermalites" which can be observed in bacteriophage DNA. The "melting components" reported here represent the separately melting of large "blocks" of fungus nuclear DNA.     

Influence of light/dark, seasonal and lunar cycles on the nuclear size of the pinealocytes of the rat

Morphological and physiological studies suggest a possible division of the pineal parenchyma into an external or "cortical" and another central or "medullar" layer. We have studied the possible influence of the light/dark, seasonal and lunar cycles on the nuclear size of the pinealocytes of the rat in both the hypothetical "cortical" and "medullar" layers. Forty male Wistar rats were used. Experiment was carried out in two seasons, winter and spring, two lunar phases, full moon and new moon, and the two circadian phases, photophase and scotophase. The nuclear volume of the pinealocytes, calculated from the Jacobj's formula, was the karyometric parameter used as measurement of the nuclear size. Main results showed that nuclear volume of the cortical pinealocytes was greater than that of the medullar pinealocytes only during the photophases of winter new-moon days and spring full moon days, whereas in all the remaining situations, the greater nuclear sizes were found in the pinealocytes of the medullar layer. These results support the existence of independent morphological variations of the pinealocyte in the central and peripheral zones of the pineal gland.     

Hepatic over-expression of peroxisome proliferator activated receptor γ2 in the ob/ob mouse model of non‐insulin dependent diabetes mellitus

The binding of nuclear factor on the promoter region of the regucalcin gene and the expression of regucalcin in the kidney cortex of rats was investigated. Nuclear extracts from kidney cortex were used for oligonucleotide competition gel mobility shift assay. An oligonucleotide between position –523 and –506 in the 5-flanking region of the rat regucalcin gene, which contains a nuclear factor I (NF1) consensus motif TTGGC(N)₆CC, competed with the probe for the binding of the nuclear protein from kidney cortex. The mutation of TTGGC in the consensus sequence caused an inhibition of the binding of nuclear factors. The binding of nuclear factor on the 5-flanking region was clearly reduced in the kidney cortex obtained at 1, 2, and 3 days after a single intraperitoneal administration of cisplatin (1.0 mg/100 g body wt) to rats. Moreover, cisplatin administration caused a remarkable decrease in regucalcin mRNA levels and regucalcin concentration in the kidney cortex. Also, serum regucalcin concentration was significantly decreased by cisplatin administration. Meanwhile, serum urea nitrogen concentration was markedly elevated by cisplatin administration. The present study demonstrates that the specific nuclear factor binds to the NF1-like sequence in the promotor region of regucalcin gene in the kidney cortex of rats, and that the nuclear factor binding and regucalcin expression are suppressed by cisplatin administration.     

A ligand-activated nuclear localization signal in cellular retinoic acid binding protein-II

Primary sequences of proteins often contain motifs that serve as "signatures" for subcellular targeting, such as a nuclear localization signal (NLS). However, many nuclear proteins do not harbor a recognizable NLS, and the pathways that mediate their nuclear translocation are unknown. This work focuses on CRABP-II, a cytosolic protein that moves to the nucleus upon binding of retinoic acid. While CRABP-II does not contain an NLS in its primary sequence, such a motif could be recognized in the protein's tertiary structure. We map the retinoic acid-induced structural rearrangements that result in the presence of this NLS in holo- but not apo-CRABP-II. The signal, whose three-dimensional configuration aligns strikingly well with a "classical" NLS, mediates ligand-induced association of CRABP-II with importin alpha and is critical for nuclear localization of the protein. The ligand-controlled NLS "switch" of CRABP-II may represent a general mechanism for posttranslational regulation of the subcellular distribution of a protein.     

Nuclear DNA,nuclear area and nuclear dry mass in thirteen species of Crotalaria (Angiospermae,Leguminosae)

Estimations on nuclear DNA content, nuclear area and nuclear dry mass were made on 13 species of Crotalaria, with the help of Vicker's M 85 microdensitometer and Vicker's interferometer. Highly significant differences for all three characters were found between species. DNA density (DNA/area) increased with increase in DNA content. The cultivated species, C. juncea had a lower DNA density relative to its DNA content.—Nuclear DNA made only a small fraction of nuclear dry mass (115). Although total dry mass and non-nucleolar nuclear dry mass showed significant regression on DNA content, the nucleolar dry mass gave a much wider scatter, indicating that nucleolar mass is not equally dependent on nuclear DNA content.     

Preselection of alarms in a hybrid system for screening of cervical cancer.

In this report, a preselection of alarms in a system for automated screening of cervical cancer based on depositing the cell sample linearly as a "cell trace" on a tape and analyzing it at different decision levels with increasing complexity, and preliminary results on analyzing cervical material with this system are discussed. The "cell trace" is analyzed with the slit-scan technique. Six parameters are computed: 1) cellular diameter; 2) nuclear diameter; 3) nuclear fluorescence (acriflavin-Feulgen) as nuclear DNA; 4) cellular fluorescence; 5) nuclear to cytoplasm ratio (N/C ratio); and 6) nuclear density. At present, only nuclear fluorescence is used to define a decision boundary between normal and potentially atypical cells. Under this criteria the slit-scan analysis leaves 5% of the events in a sample that must be rechecked at a second decision level in normal cell samples. A further reduction is expected when several slit-scan parameters are used at the first decision step. All events declared suspicious will be investigated in more detail by a two dimensional image analyzing system where the fluorescence image is generated by a laser scanning system. Results obtained in preliminary experiments are discussed in this paper.     

The origin of annulate lamellae in the oocyte of the ascidian,Boltenia villosa stimpson

Summary The formation of the extranuclear annulate lamellae has been revealed to be connected with a process of nuclear emission which is very active during the previtellogenetic stages of the Boltenia oocyte development. This process involves both of the nuclear membranes. At many spots on the surface of the nuclear envelope, the outer membrane pulls away from the inner membrane, thus forming what has been designated as blisters of various sizes and shapes. Masses of nuclear content, apparently not from the nucleolus, are pushed into the blisters. These blisters may become detached from the nuclear envelope and lie free in the cytoplasm. But in many cases, the detachment seems delayed, and in each blister many emission masses are squeezed tightly together and flat one on top of the other. These masses, in sections, may present the appearance of a stack of elongated outlines. The membrane, limiting any two adjacent masses in close contact, develop annuli. It is thus that an annulate lamella is formed. Whether an annulate lamella is formed between a pair of neighboring masses depends on their proximity. So the production of the annulate lamellae is incidental to, but not a necessary part of the process of nuclear emission. After the original outer nuclear membrane forming the blister has disintegrated, the annulate lamellae are left exposed in the cytoplasm.It is clear that, 1. both membranes of an annulate lamella are of inner nuclear membrane origin, 2. they hold between them some of the content of the enlarged perinuclear space resulting from the raising of the outer nuclear membrane when the blister is formed, and 3. the material held between any two lamellae is from the nucleus.The intranuclear annulate lamellae simply arise from the narrow pouches formed by the inner nuclear membrane towards the interior of the nucleus, and on these narrow pouches annuli are developed. So the intranuclear annulate lamellae is also composed of two membranes of an inner nuclear membrane origin holding between them a quantity of the content of the perinuclear space.Supported by Grant GM-11858 of National Institute of Health. The author is indebted to Dr. Richard Cloney of the Department of Zoology, University of Washington, for the use of the electron microscope.     

Filipin-sterol complexes in golden hamster sperm membranes with special reference to epididymal maturation

Summary The distribution of membrane filipin-sterol complexes (FSCs) was qualitatively surveyed on freeze-fracture replicas of spermatozoa from the male reproductive tract and ejaculates of golden hamster. In the head, the acrosomal plasma membrane showed the strongest filipin labeling on the principal segment, but it was absent in the quilt-like pattern areas. These latter were observed in both caput and corpus epididymal spermatozoa, but were absent in mature spermatozoa. The postacrosomal plasma membrane had few FSCs and both the outer and inner acrosomal membranes were always negative to filipin. The nuclear membrane of the principal segment was constantly filipinpositive. The nuclear membrane of the postacrosomal region had more FSCs than that of the principal segment, particularly in mature spermatozoa. Many linear, rod-like FSCs were observed on the postacrosomal nuclear membrane of mature spermatozoa, especially in the uterine spermatozoan samples. In the neck, the plasma membrane had only a few FSCs. The redundant nuclear membrane was slightly filipin-positive, while the membrane scroll of mature spermatozoa was heavily labeled. In the tail, the plasma membrane of both the middle and principal piece was moderately labeled.     

Electron Microscope Studies of Nuclear Extrusions in Pancreatic Acinar Cells of the Rat

This paper describes "blebs" protruding from the surface of the nucleus into the cytoplasm. The "blebs" are separated from the cytoplasm by 2 membranes which are continuous with the outer and inner nuclear membranes. The "blebs" contain 3 structurally distinct substances. Two of these substances (β and γ substances) are similar to extranucleolar karyoplasm and nucleolar material. The other substance (α substance) is present in every "bleb," but it cannot be readily compared to a recognizable nuclear structure. Cytoplasmic vesicles are described that are apparently different from the Golgi vesicles or the vesicular component of the ergastoplasm. It is suggested that these vesicles may be of nuclear "bleb" origin. A dark karyoplasmic zone extending from the region of the nucleolus into the nuclear "bleb" is shown. This zone may be similar in some respects to the preformed pathway ("Leitbahn") described by Altmann (3) and Hertl (28) and could reflect movement of nuclear material from the nucleolar region into the cytoplasm. The "blebs" are thought to be homologous to structures described by many light microscopists, but they are considerably larger than the nuclear "blebs" described previously by electron microscopists.     

Rigidity of the nucleus during nuclear rotation in 3T3 cells

Using near infrared microscopy and ultraviolet fluorescence microscopy of living 3T3 cells stained with the fluorochrome Hoechst 33342, we have demonstrated that the nucleoli and Hoechst 33342-stained chromocenters in the nucleus maintain a fixed pattern during nuclear rotation. We conclude that the term "nuclear rotation" refers to rotation of the entire nucleus in the cytoplasm of interphase cells, and that nuclear rotation is not an expression of karyoplasmic streaming. In conjunction with earlier results on nuclear rotation the data imply that the interface of nuclear rotation is located either between the two nuclear membranes or in the adjacent cytoplasm.     

THE DISSOCIABILITY OF DEOXYRIBONUCLEIC ACID SYNTHESIS FROM THE DEVELOPMENT OF MULTINUCLEARITY OF MUSCLE CELLS IN CULTURE

The effects of a nitrogen mustard on both the morphology and several synthetic capacities of embryonic chick skeletal muscle cells in monolayer culture have been examined. Concentrations of nitrogen mustard which profoundly inhibit deoxyribonucleic acid synthesis specifically do not inhibit the development of multinuclearity in the contractile "ribbons" which form rapidly in culture. Nitrogen mustard affects the nuclear morphology of "fibroblast-like" and multinuclear muscle cells differentially. The mononucleated cells in treated cultures exhibit extreme nuclear enlargement which distinguishes them from the multinuclear cells as well as from both types of cells in control cultures. The nuclei of the multinuclear cells which form after nitrogen mustard treatment, however, do give evidence of having been affected by the treatment. They exhibit somewhat less uniformity of size than similar cells in control cultures. Analogous differences were described by Bodenstein (3) between potentially proliferating cells and postmitotic differentiating cells, marked nuclear enlargement being characteristic of cells in the proliferative zone. The results are more compatible with the hypothesis that multinuclearity arises through successive cell fusion than through amitotic nuclear multiplication, since it is unlikely that any form of nuclear replication could occur in the absence of DNA synthesis.     

Tyrosination-detyrosination of tubulin and microtubules during the development of chick erythrocytes

The protein composition of nuclear matrices containing different amount of DNA was examined. It was found that, in matrices containing 2% to 80% of total DNA, the quantity of DNA-bound proteins remains relatively constant varying from 10% to 15% of total nuclear proteins. Electrophoretic patterns do not differ substantially, but autoradiograms with in vitro ¹²⁵I labelled proteins show quantitative variations in the actin content. Application of radioimmunoassay (RIA) enabled to determine the exact content of actin in GAT nuclei and nuclear matrices – 5 g/ml in nuclei, of which 50% are bound to DNA and 3001o being a component of the protein part of the nuclear matrix. These results are supported by electron microscopic data, where immunogold technique was performed on thin sections and spread material. The applied methods suggest that part of the nuclear actin is tightly bound (resistant to 2 M NaCI) to DNA and represents a component of the internal nuclear matrix.     

The nuclear matrix from cells of different origin. Evidence for a common set of matrix proteins

We compared the protein composition of the nuclear matrix isolated from several murine embryonal carcinoma cells and mature tissues by two-dimensional gel electrophoresis. Two nuclear matrix fractions were investigated: the "peripheral" nuclear matrix (matrix proteins that remain insoluble after reduction), and the "internal" nuclear matrix (matrix proteins released by reduction). The two subfractions have completely different protein compositions. Although numerous differences in nuclear matrix protein composition among different cell types were observed, a limited set of polypeptides common to all mouse cell types was identified. A majority of these common proteins was also present in cells from other mammalian species (i.e. rat and human). For this set of proteins, we coin the term "minimal matrix." As expected, lamin B, known to be expressed throughout differentiation, is part of the common set of peripheral nuclear matrix proteins. Lamins A and C are not because these proteins were absent from undifferentiated embryonal carcinoma cells. Since these common nuclear matrix proteins occur in all mammalian nuclear matrices analyzed so far, it is likely that they have a basic role in nuclear organization and function.     

Balbiani ring RNA content and half-life in nucleus and cytoplasm of Chironomus tentans salivary gland cells

The content of RNA with an origin in the Balbiani rings 1 and 2 (BR 1+2) has been determined in chromosomes, nuclear sap and cytoplasm of Chironomus tentans salivary gland cells. Together with information on rate and completeness of export this permits an estimation of half-life of this RNA in cytoplasm and its residence time in the nucleus. The quantities in the BR, nuclear sap, and cytoplasm are roughly related as 110200. The 75 S RNA in the nuclear sap with an origin in the BR 1+2 must to a high extent be a precursor to the cytoplasmic 75 S RNA in vivo. The half-life of the cytoplasmic component is about 20 h and the half-life (residence time) for BR 1+2 RNA in the nuclear sap around one hour. The presence of a large pool of BR RNA in the sap explains the previously observed delay in its cytoplasmic appearance in vivo.     

Divergent strategies for controlling the nuclear membrane satisfy geometric constraints during nuclear division

Eukaryotes segregate chromosomes in "open" or "closed" mitosis, depending on whether their nuclear envelopes (NEs) break down or remain intact. Here we show that the control of the nuclear surface area may determine the choice between these two modes. The dividing nucleus does not expand its surface in the fission yeast Schizosaccharomyces japonicus, confining the mitotic spindle and causing it to?buckle. The NE ruptures in anaphase, releasing the compressive stress and allowing chromosome segregation.?Blocking the NE expansion in the related species Schizosaccharomyces pombe that undergoes closed mitosis induces spindle buckling and collapse in the absence of an intrinsic NE rupture mechanism. We propose that scaling considerations could have shaped the evolution of eukaryotic mitosis by necessitating either nuclear surface expansion or the NE breakdown.