Coexpression of neuroendocrine markers and epithelial cytoskeletal proteins in bronchopulmonary neuroendocrine neoplasms.

Neuroendocrine (NE) neoplasms of the human bronchopulmonary tract were examined by electron microscopy, immunocytochemistry, and gel electrophoresis of cytoskeletal proteins from microdissected tissue samples. All samples (carcinoids, well-differentiated NE carcinoma, NE carcinomas of intermediate type, NE carcinomas of the small cell type) contained significant numbers of cells that immunostained for one or more of the following neuroendocrine markers tested: bombesin, calcitonin, ACTH, leu-enkephalin, gastrin, serotonin, somatostatin, alpha-melanocyte-stimulating hormone, vasoactive intestinal peptide, glucagon, insulin, substance P, and neuron-specific enolase. Electron microscopy revealed typical NE cell features, including variable abundant and frequently heterogeneous neurosecretory granules.

Different patterns of cytokeratin expression in the normal epithelia of the upper respiratory tract.

The distribution and type of cytokeratins present in the normal human epithelia of the nasopharynx, oropharynx, tongue, palatine tonsil, epiglottis, vocal cord, and laryngeal ventricle were studied using immunohistochemical techniques and by gel electrophoresis of cytoskeletal proteins microdissected from frozen tissues. Noncornifying stratified epithelia covering the oropharynx, tongue, surface of the palatine tonsil, pharyngeal surface of the epiglottis, and vocal cord were all found to contain cytokeratins nos. 4, 5, 6, 13, 14, and 15, together with minor amounts of cytokeratin no.

Cytokeratin patterns of human oral epithelia: differences in cytokeratin synthesis in gingival epithelium and the adjacent alveolar mucosa.

Human oral mucosa includes various epithelia that are commonly classified as lining, masticatory, and specialized epithelia. Although adjacent tissues, the gingiva and alveolar mucosa represent two different types of epithelia: the gingiva is cornified and exhibits high rate ridges, whereas the mucosa does not normally cornify and exhibits a relatively smooth-contoured borderline between the epithelium and the underlying connective tissue. We examined the cytokeratin patterns of both epithelia using one- and two-dimensional gel electrophoresis.

Patterns of expression and organization of cytokeratin intermediate filaments.

Cytokeratins are a large multigene family comprising two polypeptide types, i.e. acidic (type I) and basic (type II) ones, which are distinguished on the basis of immunological, peptide mapping, mRNA hybridization, and primary amino acid sequence data.

Distribution of vimentin, cytokeratins, and desmosomal-plaque proteins in human nephroblastoma as revealed by specific antibodies: co-existence of cell groups of different degrees of epithelial differentiation.

The distribution of cytokeratins, desmosomal-plaque proteins (desmoplakins), and vimentin in nephroblastoma tissue was studied by immunofluorescence microscopy using specific antibodies. In undifferentiated blastema cells, desmosomes, as revealed by antibodies to desmoplakins, preceded the advent of significant amounts of cytokeratins, indicating that desmosomes are early and sensitive markers of epithelial differentiation. Cytokeratin-positive tumor cells were seen in the following distribution patterns: groups of loosely arranged and scattered cells containing only scant cytokeratin fibrils surrounded by negative stroma cells; focal accumulation of cytokeratin-positive cells with cytokeratin-specific cytoplasmic fibril meshwork staining; rosettes of cytokeratin-positive cells without formation of distinct lumina, showing concentration of cytokeratin staining in the center; tubules with distinct lumina made up of cytokeratin-positive cells, with cytokeratin staining concentrated in the subapical cell portions.

Characterization of bovine keratin genes: similarities of exon patterns in genes coding for different keratins.

Four different genomic clones which contain the genes coding for epidermal keratins Ia (mol. wt. approximately 68 000), Ib (68 000), III (60 000) and VIb (54 500) have been selected using cDNA probes and identified by hybrid-selection translation.

Vimentin filament-desmosome cytoskeleton of diverse types of human meningiomas. A distinctive diagnostic feature.

Ten human meningiomas of different histologic subtypes (endotheliomatous, transitional, fibroblastic, and angioblastic) were examined for the expression of intermediate-sized filaments (IF) and desmosomal plaque proteins (desmoplakins I and II), using immunofluorescence and immunoelectron microscopy. All meningiomas gave a strong positive reaction for vimentin as well as for desmoplakins. IF of the cytokeratin type, desmin IF, and glial filaments were not detected in any of these tumors.

Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes.

Nuclei of amphibian oocytes contain large amounts of actin, mostly in unpolymerized or short-polymer form. When antibodies to actin or actin-binding proteins (fragmin and the actin modulator from mammalian smooth muscle) are injected into nuclei of living oocytes of Pleurodeles waltlii, transcription of the lampbrush chromosomes, but not of the rRNA genes, is inhibited. When transcription is repressed by drugs or RNA is digested by microinjection of RNAase into oocyte nuclei, an extensive meshwork of actin filament bundles is seen in association with the isolated lampbrush chromosomes.

Identification of two types of keratin polypeptides within the acidic cytokeratin subfamily I.

Cytoskeletal filaments of the alpha-keratin type (cytokeratins) are a characteristic of epithelial cells. In diverse mammals (man, cow and rodents) these cytokeratins consist of a family of approximately 20 polypeptides, which may be divided into the more acidic (I) and the more basic (II) subfamilies. These two subfamilies show only limited amino acid sequence homology.

Transient change of organization of vimentin filaments during mitosis as demonstrated by a monoclonal antibody.

A monoclonal antibody specific for vimentin is described which, by immunofluorescence and immunoelectron microscopy, decorates fibrillar and/or granular structures in mitotic and early postmitotic cells but does not react with vimentin filaments of interphase stages of various cultured cells (rat vascular smooth muscle-derived cell line RVF-SM; SV40-transformed human fibroblasts; bovine kidney epithelial cells of line MDBK). These observations indicate that the organization of vimentin filaments varies during the cell cycle, undergoing a perimitotic change of filament organization. These changes of vimentin filaments are described in relation to those reported for cytokeratin filaments of various epithelial and carcinoma cells.

Heterotypic tetramer (A2D2) complexes of non-epidermal keratins isolated from cytoskeletons of rat hepatocytes and hepatoma cells.

Cytoskeletal residues obtained after extraction of rat liver and cultured rat hepatoma cells (line MH1C1) were used to isolate cytokeratin subunit complexes by solubilization in low salt buffer containing 4 M-urea. Alternatively, the complexes were prepared by solubilization of total cytoskeletal proteins in 9.5 M-urea or 6 M-guanidinium hydrochloride (Gu .

Intermediate filaments of normal and neoplastic tissues of the female genital tract with emphasis on problems of differential tumor diagnosis.

Cytokeratins of normal epithelia and of some neoplasms of the female genital tract were studied by immunofluorescence microscopy of frozen sections and by two-dimensional gel electrophoresis of cytoskeletal proteins from microdissected tissues. All normal epithelia were stained with the monoclonal cytokeratin antibody KG 8.13 whereas certain monoclonal antibodies stained only simple epithelia.

Identification and localization of a novel nucleolar protein of high molecular weight by a monoclonal antibody.

A monoclonal murine antibody (No-114) is described which reacts specifically with a polypeptide of molecular weight (Mr) 180 000 present in low-speed nuclear pellets from oocytes and somatic cells of Xenopus laevis and X. borealis and in isolated amplified nucleoli. Two-dimensional gel electrophoresis has revealed the acidic nature of this polypeptide (isoelectric at pH of ca 4.

Karyophobic proteins. A category of abundant soluble proteins which accumulate in the cytoplasm.

The cytoplasm of oocytes of Xenopus laevis is enriched in several soluble proteins which are either absent from the nucleus or are present there at very low concentrations. These molecules, collectively referred to as karyophobic (from the Greek verbs and which are meant here in the sense of "to be afraid of" or "to avoid") proteins represent more than 20% of the total soluble cytoplasmic proteins and include some of the most abundant soluble cellular components. They may be recovered from high-speed supernatant (S-100) fractions and, following sucrose gradient centrifugation, most of them appear in the form of complexes smaller than 8.

Differences of supranucleosomal organization in different kinds of chromatin: cell type-specific globular subunits containing different numbers of nucleosomes.

Fractions of homogeneously-sized supranucleosomal particles can be obtained in high yield and purity from various types of cells by brief micrococcal nuclease digestion (10 or 20 s) of condensed chromatin in 100 mM NaCl followed by sucrose gradient centrifugation and agarose gel electrophoresis. These chromatin particles, which contain only DNA and histones, differed according to cell type. Sea urchin spermatozoa (Paracentrotus lividus) gave rise to heavy particles (ca.

Cell type-specific expression of bovine keratin genes as demonstrated by the use of complementary DNA clones.

Cytokeratins are a family of polypeptides that form the intermediate-sized filament characteristic of epithelial cells. The cytoskeletons of different types of epithelial cells have been reported to possess specific combinations of the members of this protein family. Therefore, we have sought to examine the correspondence between such differential protein expression and the expression of cytokeratin genes at the nucleic acid level.

Integration of different keratins into the same filament system after microinjection of mRNA for epidermal keratins into kidney epithelial cells.

We have isolated poly (A)+ RNA, highly enriched in keratin mRNA from bovine muzzle epidermis, and injected it into epithelial cells of a different type, i.e., cultured kidney epithelial cells of the same (MDBK) or taxonomically distant (PtK2) species.

Attachment of vimentin filaments to desmosomal plaques in human meningiomal cells and arachnoidal tissue.

Desmosomal proteins are co-expressed with intermediate-sized filaments (IF) of the cytokeratin type in epithelial cells, and these IF are firmly attached to the desmosomal plaque. In meningiomal and certain arachnoidal cells, however, vimentin IF are attached to desmosomal plaques. Meningiomas obtained after surgery, arachnoid "membranes", and arachnoid granulations at autopsy, as well as meningiomal cells grown in short-term culture have been examined by single and double immunofluorescence and immunoelectron microscopy using antibodies to desmoplakins, vimentin, cytokeratins, glial filament protein, neurofilament protein, and procollagen.

Electron microscopic immunolocalization of a karyoskeletal protein of molecular weight 145 000 in nucleoli and perinucleolar bodies of Xenopus laevis.

Amplified nucleoli of Xenopus laevis oocytes contain a major karyoskeletal protein of Mr 145 000 insoluble in low- and high-salt buffer as well as in non-denaturing detergents. Electron microscopic localization on native and high-salt extracted nucleoli using specific murine antibodies against this polypeptide and gold-coupled antibodies for visualization reveals that the Mr 145 000 protein is located in coils of filaments of ca 4 nm diameter. In addition, this protein occurs in the medusoid filament bodies (MFBs) present in the nucleolar cortex and free in the nucleoplasm.

Karyoskeletal proteins and the organization of the amphibian oocyte nucleus.

We have investigated the existence of structural components in the nucleus of the oocyte of Xenopus laevis and other amphibia that are insoluble in non-denaturing detergents and buffers of low and high ionic strength. These cells are particularly suitable for such studies as they have a high frequency of extrachromosomal amplified nucleoli and pore complexes of the nuclear envelope. Using biochemical and immunological techniques, we have shown these structures to contain only two major proteins.

Cytokeratins in normal lung and lung carcinomas. I. Adenocarcinomas, squamous cell carcinomas and cultured cell lines.

The various epithelial cells of the lower respiratory tract and the carcinomas derived from them differ markedly in their differentiation characteristics. Using immunofluorescence microscopy and two-dimensional gel electrophoresis of cytoskeletal proteins from microdissected tissues we have considered whether cytokeratin polypeptides can serve as markers of cell differentiation in epithelia from various parts of the human and bovine lower respiratory tract. In addition , we have compared these protein patterns with those found in the two commonest types of human lung carcinoma and in several cultured lung carcinoma cell lines.