A comprehensive study on the isolation and characterization of the HeLa S3 nuclear matrix

1991 ◽  
Vol 98 (3) ◽  
pp. 281-291
Author(s):  
P. Belgrader ◽  
A.J. Siegel ◽  
R. Berezney
Keyword(s):  
Nuclear Matrix ◽  
Intermediate Filament ◽  
Structural Integrity ◽  
Rnase A ◽  
Matrix Proteins ◽  
Intermediate Filament Proteins ◽  
Isolation And Characterization ◽  
Hela S3

Different agents have been employed to extract the histones and other soluble components from isolated HeLa S3 nuclei during nuclear matrix isolation. We report that 0.2M (NH4)2SO4 is a milder extracting agent than NaCl and LIS (lithium 3,5-diiodosalicylate), on the basis of the apparent preservation of the elaborate fibrogranular network and the residual nucleolus that resemble the in situ structures in whole cells and nuclei, minimal aggregation, and sufficient solubilization of DNA and histones. The importance of intermolecular disulfide bonds, RNA and 37 degrees C stabilization on the structural integrity of the nuclear matrix was examined in detail using sulfydryl alkylating, reducing and oxidizing agents, and RNase A. The data suggest that any disulfides formed during the isolation are not essential for maintaining the structural integrity of the in vitro matrix. However, structural integrity of the matrix is dependent upon RNA and to some degree on disulfides that presumably existed in situ. Sodium tetrathionate and 37 degrees C stabilization of isolated nuclei resulted in nuclear matrices containing an approximately twofold greater amount of protein, RNA and DNA than control preparations. The 37 degrees C incubation, unlike the sodium tetrathionate stabilization, does not appear to induce intermolecular disulfide bond formation. Neither stabilizations resulted in significant differences of the major matrix polypeptide pattern on two-dimensional (2-D) gels stained with Coomassie Blue as compared to that of unstabilized matrix. The major nuclear matrix proteins, other than the lamins, did not react to the Pruss murine monoclonal antibody (IFA) that recognizes all known intermediate filament proteins, suggesting that the internal matrix proteins are not related to the lamins in intermediate filament-like quality.

scholarly journals HIGH-YIELD PREPARATION OF ISOLATED RAT LIVER PARENCHYMAL CELLS

1969 ◽  
Vol 43 (3) ◽  
pp. 506-520 ◽  
Author(s):  
M. N. Berry ◽  
D. S. Friend
Keyword(s):  
Gap Junctions ◽  
Rat Liver ◽  
Structural Integrity ◽  
Cell Injury ◽  
High Yield ◽  
Isolated Cells ◽  
Nylon Mesh ◽  
Parenchymal Cells

A new technique employing continuous recirculating perfusion of the rat liver in situ, shaking of the liver in buffer in vitro, and filtration of the tissue through nylon mesh, results in the conversion of about 50% of the liver into intact, isolated parenchymal cells. The perfusion media consist of: (a) calcium-free Hanks' solution containing 0.05% collagenase and 0.10% hyaluronidase, and (b) magnesium and calcium-free Hanks' solution containing 2 mM ethylenediaminetetraacetate. Biochemical and morphologic studies indicate that the isolated cells are viable. They respire in a medium containing calcium ions, synthesize glucose from lactate, are impermeable to inulin, do not stain with trypan blue, and retain their structural integrity. Electron microscopy of biopsies taken during and after perfusion reveals that desmosomes are quickly cleaved. Hemidesmosome-containing areas of the cell membrane invaginate and appear to pinch off and migrate centrally. Tight and gap junctions, however, persist on the intact, isolated cells, retaining small segments of cytoplasm from formerly apposing parenchymal cells. Cells which do not retain tight and gap junctions display swelling of Golgi vacuoles and vacuoles in the peripheral cytoplasm. Cytoplasmic vacuolization in a small percentage of cells and potassium loss are the only indications of cell injury detected. By other parameters measured, the isolated cells are comparable to normal hepatic parenchymal cells in situ in appearance and function.

scholarly journals Tissue type-specific expression of intermediate filament proteins in a cultured epithelial cell line from bovine mammary gland

1983 ◽  
Vol 96 (1) ◽  
pp. 37-50 ◽  
Author(s):  
E Schmid ◽  
DL Schiller ◽  
C Grund ◽  
J Stadler ◽  
WW Franke
Keyword(s):  
Mammary Gland ◽  
Epithelial Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Intermediate Filament ◽  
Striking Difference ◽  
Intermediate Filament Proteins ◽  
Cell Clones ◽  
Vimentin Filaments

Different clonal cell lines have been isolated from cultures of mammary gland epithelium of lactating cow's udder and have been grown in culture media containing high concentrations of hydrocortisone, insulin, and prolactin. These cell (BMGE+H), which grow in monolayers of typical epithelial appearance, are not tightly packed, but leave intercellular spaces spanned by desmosomal bridges. The cells contain extended arrays of cytokeratin fibrils, arranged in bundles attached to desmosomes. Gel electophoresis show that they synthesize cytokeratins similar, if not identical, to those found in bovine epidermis and udder, including two large (mol wt 58,500 and 59,000) and basic (pH range: 7-8) and two small (mol wt 45,500 and 50,000) and acidic (pH 5.32 and 5.36) components that also occur in phosphorylated forms. Two further cytokeratins of mol wts 44,000 (approximately pH 5.7) and 53,000 (pH 6.3) are detected as minor cytokeratins in some cell clones. BMGE+H cells do not produce vimentin filaments as determined by immunofluorescence microscopy and gel electrophoresis. By contrast, BMGE-H cells, which have emerged from the same original culture but have been grown without hormones added, are not only morphologically different, but also contain vimentin filaments and a different set of cytokeratins, the most striking difference being the absence of the two acidic cytokeratins of mol wt 50,000 and 45,500. Cells of the BMGE+H line are characterized by an unusual epithelial morphology and represent the first example of a nonmalignant permanent cell line in vitro that produces cytokeratin but not vimentin filaments. The results show that (a) tissue-specific patterns of intermediate filament expression can be maintained in permanent epithelial cell lines in culture, at least under certain growth conditions; (b) loss of expression of relatively large, basic cytokeratins is not an inevitable consequence of growth of epithelial cells in vitro. Our results further show that, during culturing, different cell clones with different cytoskeletal composition can emerge from the same cell population and suggest that the presence of certain hormones may have an influence on the expression of intermediate filament proteins.

Interaction of plakophilins with desmoplakin and intermediate filament proteins: an in vitro analysis

2000 ◽  
Vol 113 (13) ◽  
pp. 2471-2483 ◽  
Author(s):  
I. Hofmann ◽  
C. Mertens ◽  
M. Brettel ◽  
V. Nimmrich ◽  
M. Schnolzer ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intermediate Filament ◽  
Solid Phase ◽  
Specific Interaction ◽  
Binding Assays ◽  
Intermediate Filament Proteins ◽  
Amino Terminal ◽  
Vitro Analysis

Plakophilin 1 and 2 (PKP1, PKP2) are members of the arm-repeat protein family. They are both constitutively expressed in most vertebrate cells, in two splice forms named a and b, and display a remarkable dual location: they occur in the nuclei of cells and, in epithelial cells, at the plasma membrane within the desmosomal plaques. We have shown by solid phase-binding assays that both PKP1a and PKP2a bind to intermediate filament (IF) proteins, in particular to cytokeratins (CKs) from epidermal as well as simple epithelial cells and, to some extent, to vimentin. In line with this we show that recombinant PKP1a binds strongly to IFs assembled in vitro from CKs 8/18, 5/14, vimentin or desmin and integrates them into thick (up to 120 nm in diameter) IF bundles extending for several microm. The basic amino-terminal, non-arm-repeat domain of PKP1a is necessary and sufficient for this specific interaction as shown by blot overlay and centrifugation experiments. In particular, the binding of PKP1a to IF proteins is saturable at an approximately equimolar ratio. In extracts from HaCaT cells, distinct soluble complexes containing PKP1a and desmoplakin I (DPI) have been identified by co-immunoprecipitation and sucrose density fractionation. The significance of these interactions of PKP1a with IF proteins on the one hand and desmoplakin on the other is discussed in relation to the fact that PKP1a is not bound - and does not bind - to extended IFs in vivo. We postulate that (1) effective cellular regulatory mechanisms exist that prevent plakophilins from unscheduled IF-binding, and (2) specific desmoplakin interactions with either PKP1, PKP2 or PKP3, or combinations thereof, are involved in the selective recruitment of plakophilins to the desmosomal plaques.

Isolation and Characterization of Human Epidermal Stem Cells

1996 ◽  
Vol 91 (2) ◽  
pp. 141-146 ◽  
Author(s):  
P. H. Jones
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Matrix Proteins ◽  
Stem Cell Markers ◽  
Epidermal Stem Cells ◽  
Cell Behaviour ◽  
Isolation And Characterization ◽  
Integrin Family

1. The keratinocytes in human epidermis are constantly turned over and replaced by a population of stem cells located in the basal epidermal layer. Until recently there were no markers allowing the isolation of viable epidermal stem cells. However, it has now been shown that epidermal stem cells can be isolated both in vitro and direct from the epidermis as they express high levels of functional β1 integrin family receptors for extracellular matrix proteins. 2. The evidence for integrins as stem cell markers and the insights that have been gained into stem cell behaviour are reviewed.

Proteolysis of vimentin and desmin by the Ca2+-activated proteinase specific for these intermediate filament proteins

1983 ◽  
Vol 3 (6) ◽  
pp. 1146-1156
Author(s):  
W J Nelson ◽  
P Traub
Keyword(s):  
Intermediate Filament ◽  
Degradation Products ◽  
Polyacrylamide Gel Electrophoresis ◽  
Phosphorylation Site ◽  
Limited Proteolysis ◽  
Complete Removal ◽  
Product Inhibition ◽  
Nucleic Acid Binding ◽  
Intermediate Filament Proteins

The degradation of vimentin and desmin by the Ca2+-activated proteinase specific for these intermediate filament proteins proceeds in two stages in the form of a limited proteolysis. At first, the reaction is very rapid, with the stepwise and complete removal of a peptide (ca. 9,000 daltons) from the N-terminal of vimentin and desmin. This results in the production of a characteristic "staircase" of degradation products, as seen in two-dimensional polyacrylamide gel electrophoresis. The second stage of proteolysis is characterized by the accumulation of peptides which are resistant to further proteolysis; this is due not to product inhibition but to the fact that these peptides are not substrates for the proteinase and therefore do not protect the latter from inactivation (autodigestion). In vitro phosphorylation of the substrates does not affect proteinase activity, probably because the phosphorylation site is located towards the C-terminal of the molecules. The specific and limited proteolysis of vimentin and desmin results in the deletion of the nucleic acid binding and filament assembly site of these proteins, indicating that the Ca2+-activated proteinase plays a role in regulating the function(s) of these intermediate filament proteins, rather than their simple turnover during the cell cycle.

scholarly journals alpha-Internexin, a 66-kD intermediate filament-binding protein from mammalian central nervous tissues.

1985 ◽  
Vol 101 (4) ◽  
pp. 1316-1322 ◽  
Author(s):  
J S Pachter ◽  
R K Liem
Keyword(s):  
Optic Nerve ◽  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Peptide Mapping ◽  
Exchange Chromatography ◽  
Filament Assembly ◽  
Antigen Antibody

In this paper we describe a 66-kD protein that co-purifies with intermediate filaments from rat optic nerve and spinal cord but can be separated further by ion-exchange chromatography. This protein is distinct from the 68-kD neurofilament subunit protein as judged by isoelectric focusing, immunoblotting, peptide mapping, and tests of polymerization competence. This protein is avidly recognized by the monoclonal anti-intermediate filament antigen antibody, previously demonstrated to recognize a common antigenic determinant in all five known classes of intermediate filaments. Also, when isolated this protein binds to various intermediate filament subunit proteins, which suggests an in vivo interaction with the intermediate filament cytoskeleton, and it appears to be axonally transported in the rat optic nerve. Because of this ability to bind to intermediate filaments in situ and in vitro we have named this protein alpha-internexin. A possible functional role for the protein in organizing filament assembly and distribution is discussed.

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