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1991

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Articles 1 - 25 of 25

Full-Text Articles in Cell Biology

Discrete Nuclear Domains Of Poly(A) Rna And Their Relationship To The Functional Organization Of The Nucleus, Kenneth C. Carter, Krishan L. Taneja, Jeanne B. Lawrence Dec 1991

Discrete Nuclear Domains Of Poly(A) Rna And Their Relationship To The Functional Organization Of The Nucleus, Kenneth C. Carter, Krishan L. Taneja, Jeanne B. Lawrence

Open Access Articles

The functional organization of the nucleus was studied using a fluorescence microscopy approach which allowed integration of positional information for RNA, DNA, and proteins. In cells from sea urchin to human, nuclear poly(A) RNA was found concentrated primarily within several discrete "transcript domains" which often surrounded nucleoli. Concentrations of poly(A) RNA were coincident with snRNP antigen clusters, providing evidence for the localization of pre-mRNA splicing at these sites. The spatial relationship of transcript domains with respect to various classes of DNA was established, in that the poly(A) RNA-rich regions coincided with discrete regions of low DNA density ...


The Length Of Homology Required For Gene Targeting In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley Nov 1991

The Length Of Homology Required For Gene Targeting In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley

Rivera Lab Publications

Homologous recombination has been used to introduce site-specific mutations into murine embryonic stem (ES) cells with both insertion and replacement vectors. In this study, we compared the frequency of gene targeting with various lengths of homology and found a dramatic increase in targeting with an increase in homology from 1.3 to 6.8 kb. We examined in detail the relationship between the length of homology and the gene-targeting frequency for replacement vectors and found that a critical length of homology is needed for targeting. Adding greater lengths of homology to this critical length has less of an effect on ...


Target Frequency And Integration Pattern For Insertion And Replacement Vectors In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Christine Chang, Allan Bradley Sep 1991

Target Frequency And Integration Pattern For Insertion And Replacement Vectors In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Christine Chang, Allan Bradley

Rivera Lab Publications

Gene targeting has been used to direct mutations into specific chromosomal loci in murine embryonic stem (ES) cells. The altered locus can be studied in vivo with chimeras and, if the mutated cells contribute to the germ line, in their offspring. Although homologous recombination is the basis for the widely used gene targeting techniques, to date, the mechanism of homologous recombination between a vector and the chromosomal target in mammalian cells is essentially unknown. Here we look at the nature of gene targeting in ES cells by comparing an insertion vector with replacement vectors that target hprt. We found that ...


Characterization Of Two Temperature-Sensitive Mutants Of Escherichia Coli Exhibiting An Altered L22 Ribosomal Protein, Bonnie A. Burnette-Vick Aug 1991

Characterization Of Two Temperature-Sensitive Mutants Of Escherichia Coli Exhibiting An Altered L22 Ribosomal Protein, Bonnie A. Burnette-Vick

Electronic Theses and Dissertations

Analysis of E. coli strains SK1047 and SK1048 have shown them to be temperature-sensitive, protein-synthesis deficient. An alteration in ribosomal protein L22 was detected in both strains using two dimensional gel electrophoresis. Protein L22 was purified from both strains by reversed phase high performance liquid chromatography and from two dimensional electrophoretic gels. Purified ribosomal protein L22 was labeled by reductive methylation and used in 23S RNA binding assays with and without ribosomal protein L4. At the permissive temperature, protein L22 from SK1047 bound less efficiently than the control while protein L22 from SK1048 bound as efficiently as the control. At ...


Ribosome Binding To The Endoplasmic Reticulum: A 180-Kd Protein Identified By Crosslinking To Membrane-Bound Ribosomes Is Not Required For Ribosome Binding Activity, Pallia G. Collins, Reid Gilmore Aug 1991

Ribosome Binding To The Endoplasmic Reticulum: A 180-Kd Protein Identified By Crosslinking To Membrane-Bound Ribosomes Is Not Required For Ribosome Binding Activity, Pallia G. Collins, Reid Gilmore

Open Access Articles

We have used the membrane-impermeable, thiol-cleavable, crosslinker 3,3'-dithio bis (sulfosuccinimidylpropionate) to identify proteins that are in the vicinity of membrane-bound ribosomes of the RER. A specific subset of RER proteins was reproducibly crosslinked to the ribosome. Immunoblot analysis of the crosslinked products with antibodies raised against signal recognition particle receptor, ribophorin I, and the 35-kD subunit of the signal sequence receptor demonstrated that these translocation components had been crosslinked to the ribosome, but each to a different extent. The most prominent polypeptide among the crosslinked products was a 180-kD protein that has recently been proposed to be a ...


The Submembrane Machinery For Nicotinic Acetylcholine Receptor Clustering, S. C. Froehner Jul 1991

The Submembrane Machinery For Nicotinic Acetylcholine Receptor Clustering, S. C. Froehner

Open Dartmouth: Faculty Open Access Scholarship

No abstract provided.


Er Translocation Intermediates Are Adjacent To A Nonglycosylated 34-Kd Integral Membrane Protein, Kennan V. Kellaris, Sharon Bowen, Reid Gilmore Jul 1991

Er Translocation Intermediates Are Adjacent To A Nonglycosylated 34-Kd Integral Membrane Protein, Kennan V. Kellaris, Sharon Bowen, Reid Gilmore

Open Access Articles

We have used the homobifunctional cross-linking reagent disuccinimidyl suberate (DSS) to identify proteins that are adjacent to nascent polypeptides undergoing translocations across mammalian rough ER. Translocation intermediates were assembled by supplementing cell free translations of truncated mRNAs with the signal recognition particle (SRP) and microsomal membrane vesicles. Two prominent cross-linked products of 45 and 64 kD were detected. The 64-kD product was obtained when the cell free translation contained SRP, while formation of the 45-kD product required both SRP and translocation competent microsomal membrane vesicles. In agreement with previous investigators, we suggest that the 64-kD product arises by cross-linking of ...


A Highly Polymorphic Dinucleotide Repeat On The Proximal Short Arm Of The Human X Chromosome: Linkage Mapping Of The Synapsin I/A-Raf-1 Genes, Cordula U. Kirchgessner, James A. Trofatter, Melanie M. Mahtani, Huntington F. Willard, Louis J. Degennaro Jul 1991

A Highly Polymorphic Dinucleotide Repeat On The Proximal Short Arm Of The Human X Chromosome: Linkage Mapping Of The Synapsin I/A-Raf-1 Genes, Cordula U. Kirchgessner, James A. Trofatter, Melanie M. Mahtani, Huntington F. Willard, Louis J. Degennaro

Open Access Articles

A compound (AC)n repeat located 1,000 bp downstream from the human synapsin I gene and within the last intron of the A-raf-1 gene has been identified. DNA data-base comparisons of the sequences surrounding the repeat indicate that the synapsin I gene and the A-raf-1 gene lie immediately adjacent to each other, in opposite orientation. PCR amplification of this synapsin I/A-raf-1 associated repeat by using total genomic DNA from members of the 40 reference pedigree families of the Centre d'Etude du Polymorphisme Humaine showed it to be highly polymorphic, with a PIC value of .84 and a ...


Mouse Mast Cell Proteases: Induction, Molecular Cloning, And Characterization, Wei Chu May 1991

Mouse Mast Cell Proteases: Induction, Molecular Cloning, And Characterization, Wei Chu

Electronic Theses and Dissertations

Tryptase, a mast cell-specific serine protease with trypsin-like specificity, has been identified in a mouse mast cell line (ABFTL-6) based on it's enzymatic activity, inhibition properties, and cross-reactivity to a human mast cell tryptase antibody. The effects of fibroblast-conditioned medium and sodium butyrate on ABFTL-6 mast cell differentiation and tryptase expression have been examined. ABFTL-6 mouse mast cells undergo phenotypic changes upon culturing in media supplemented with fibroblast-conditioned media at 50% or 1 mM sodium butyrate. The induced cells increased in size, had larger and more metachromatic cytoplasmic granules, and increased their total cellular protein about four-fold. Tryptase activity ...


Immunohistochemical Labeling Of Vinculin In The Embryonic Chick, Jon Bullman Apr 1991

Immunohistochemical Labeling Of Vinculin In The Embryonic Chick, Jon Bullman

Life and Environmental Sciences Undergraduate Theses

Vinculin is an intracellular protein that links the cytoskeleton with the plasma membrane. It is found in all adhering junctions--both cell-cell and cell-surface. Its location puts it at the center of a fundamental process of embryogenesis--the epithelial-mesenchymal transition. An immunohistochemical labelling technique for the localization of vinculin was developed. This technique could be used in an attempt to understand the fundamental processes of development by applying it to the study of epithelialmesenchymal transitions in the somite of a chick embryo.


Immunohistochemical Localization Of A-Cam In The Embryonic Chick, Larie Smoyer Apr 1991

Immunohistochemical Localization Of A-Cam In The Embryonic Chick, Larie Smoyer

Life and Environmental Sciences Undergraduate Theses

Tissue sections of chick embryos were immunohisto- chemically stained for the presence of A-CAM, a cell surface protein associated with epithelial tissues. This was to determine an effective method of immunohistochemical staining for A-CAM and to study the distribution of A-CAM in the embryonic chick. A method of immunohistochemical staining was developed.


Identification Of Laminin Domains That Promote Tumor Cell Adhesion, Corby Freitag Apr 1991

Identification Of Laminin Domains That Promote Tumor Cell Adhesion, Corby Freitag

Life and Environmental Sciences Undergraduate Theses

The process of metastasis requires tumor cells to migrate through the basement membrane which consists of laminin, a glycoprotein which promotes the adhesion of HT-1080 fibrosarcoma cells. The present study was designed to test four peptides, corresponding to short sequences of the intact laminin molecule, for cell adhesion-promoting activity. By using three different cell migration assays, the four peptides were monitored for their cell adhesive-promoting activity. Results were obtained showing some cell adhesive-promoting activity from all four peptides.


Preservation Of Specific Rna Distribution Within The Chromatin-Depleted Nuclear Substructure Demonstrated By In Situ Hybridization Coupled With Biochemical Fractionation, Yigong P. Xing, Jeanne B. Lawrence Mar 1991

Preservation Of Specific Rna Distribution Within The Chromatin-Depleted Nuclear Substructure Demonstrated By In Situ Hybridization Coupled With Biochemical Fractionation, Yigong P. Xing, Jeanne B. Lawrence

GSBS Student Publications

Biochemical fractionation procedures previously shown to remove 95% of cellular protein, DNA, and phospholipid, were combined with fluorescence in situ hybridization to provide a critical evaluation of the retention and spatial preservation of specific primary transcripts within the chromatin-depleted nuclear substructure, operationally defined as the nuclear "matrix." This unique approach made it possible to directly address whether nuclear extraction procedures preserve, create, or destroy ribonucleoprotein filament structures. Comparison of nuclei before and after fractionation demonstrated that localized foci or "tracks" of specific nRNA are unambiguously retained in the nuclear matrix preparation. Two well-characterized nuclear fractionation procedures were used and three ...


Modulation Of Hexokinase Association With Mitochondria Analyzed With Quantitative Three-Dimensional Confocal Microscopy, Ronald M. Lynch, Kevin E. Fogarty, Fredric S. Fay Feb 1991

Modulation Of Hexokinase Association With Mitochondria Analyzed With Quantitative Three-Dimensional Confocal Microscopy, Ronald M. Lynch, Kevin E. Fogarty, Fredric S. Fay

Open Access Articles

Hexokinase isozyme I is proposed to be associated with mitochondria in vivo. Moreover, it has been suggested that this association is modulated in coordination with changes in cell metabolic state. To test these hypotheses, we analyzed the subcellular distribution of hexokinase relative to mitochondria in paraformaldehyde-fixed astrocytes using immunocytochemistry and quantitative three-dimensional confocal microscopy. Analysis of the extent of colocalization between hexokinase and mitochondria revealed that approximately 70% of cellular hexokinase is associated with mitochondria under basal metabolic conditions. In contrast to the immunocytochemical studies, between 15 to 40% of cellular hexokinase was found to be associated with mitochondria after ...


Photoreactivation Of Uv-Induced Damage In G1 Phase Xenopus Cells That Leads To A Sister Chromatid Exchanged And Cell Death, Dawn Laswell, Jennifer Barber, H. Gaston Griggs Jan 1991

Photoreactivation Of Uv-Induced Damage In G1 Phase Xenopus Cells That Leads To A Sister Chromatid Exchanged And Cell Death, Dawn Laswell, Jennifer Barber, H. Gaston Griggs

Journal of the Arkansas Academy of Science

Experiments were conducted with the A87 Xenopus tissue culture cell line which centered on use of the line's efficient photoreactivation (PR) mechanism to: (1) determine the extent to which sister chromatid exchanges (SCEs), induced by exposing early G1 phase cells to low UV fluenced, are photoreactivable, and (2) determine the extent to which the photoreactivable SCEs resulting from these low UV fluences constitute lethal lesions. For the first determination, UV fluences - SCE frequency relations and UV fluence + PR fluence - SCE frequency relations were established for UV fluences in the range 0-12 J/m2 and a single PR fluence of ...


In Vitro Desmin Assembly And In Vivo Changes In Developing Smooth Muscle , Rong-Ghi Robert Chou Jan 1991

In Vitro Desmin Assembly And In Vivo Changes In Developing Smooth Muscle , Rong-Ghi Robert Chou

Retrospective Theses and Dissertations

This dissertation is divided into two principal parts. The purpose of the first part was to investigate the effects of cations and temperature on the critical concentration of desmin required for filament assembly by using tow independent assays, namely, turbidity and centrifugation. Assembly was done in the presence of 2 mM Ca[superscript]2+, 2 mM Mg[superscript]2+ or 150 mM Na[superscript]+ at 2, 22 and 37°C. Similar values for critical concentration were obtained by both assays. As temperature increased, critical concentration decreased for each cation. Critical concentration was lowest in the presence of Ca[superscript]2 ...


Selected Properties Of The Cytoskeletal Protein Synemin And Its Interactions With Proteins At The Muscle Z-Line , Stephan Roman Bilak Jan 1991

Selected Properties Of The Cytoskeletal Protein Synemin And Its Interactions With Proteins At The Muscle Z-Line , Stephan Roman Bilak

Retrospective Theses and Dissertations

The primary purposes of this study were to: (1) examine selected properties of the intermediate filament-associated protein (IFAP), synemin, (2) identify synemin (or a synemin homolog) in adult mammalian muscle, and (3) examine synemin's ability to interact with proteins located at the myofibrillar Z-line. An integrated biochemical, immunological, and ultrastructural approach was used;Synemin (230 kD) was solubilized from an actomyosin-extracted avian smooth muscle residue and purified by chromatography on two hydroxyapatite columns and one DEAE-Sephacel column in the presence of 6 M urea. Renatured, soluble synemin was obtained by removal of the urea by dialysis against 10 mM ...


Identification Of Intermediate Filaments And Their Proteins In Mature Mammalian Striated Muscle , Masako Maria Bilak Jan 1991

Identification Of Intermediate Filaments And Their Proteins In Mature Mammalian Striated Muscle , Masako Maria Bilak

Retrospective Theses and Dissertations

The major purposes of this study were to: (1) clearly identify intermediate filaments (IFs) and elucidate their structural arrangement at the myofibrillar Z-lines in non-diseased, mature mammalian striated muscle cells, and (2) determine the localization of constituent proteins of the IFs by immunogold localization. IFs running transversely to the long axis of the cell and connecting Z-lines of adjacent myofibrils were identified by high resolution transmission electron microscopy (TEM) of plastic-embedded porcine semitendinosus muscle, especially in areas of cells where myofibrils were less tightly packed. When the plane of section included the periphery of myofibrils at their Z-lines, examination indicated ...


Cadmium Modification Of Cell Growth And Specific Gene Expression In Normal Rat-Kidney Fibroblast Cells , Ning Tang Jan 1991

Cadmium Modification Of Cell Growth And Specific Gene Expression In Normal Rat-Kidney Fibroblast Cells , Ning Tang

Retrospective Theses and Dissertations

The main purpose of this work was to examine how cadmium modifies cell growth and specific gene expression in normal rat kidney fibroblast cells;It was found that cadmium inhibits EGF-induced DNA synthesis, but not myc mRNA accumulation and amino acid incorporation;To further study cadmium's function in these cells, clonal subpopulations were isolated from NRK-49F NM cells. It was found that subclones N1 and N4 show opposite responses to TGF-beta and they also have different cadmium sensitivities. Thus, a subclone N1 which shows highest cadmium sensitivity and also TGF-beta sensitivity in inhibiting EGF-induced DNA synthesis was chosen for ...


In Vitro Culture Systems Of Hybrid Aspen As Tools For Tree Improvement Programs And Commercial Applications , Sung Ho Son Jan 1991

In Vitro Culture Systems Of Hybrid Aspen As Tools For Tree Improvement Programs And Commercial Applications , Sung Ho Son

Retrospective Theses and Dissertations

Tree improvement programs have two important components: (1) induction of desirable types of genetic variation by breeding, and (2) selection and maintenance of the traits by sexual or asexual propagation methods. By combining tissue culture systems and morden DNA technology with conventional breeding methods, both aspects of tree improvement will benfit. New tissue culture systems are also important to the development of commercial applications of improved trees;Therefore, several new approaches to the in vitro culture of hybrid aspen (Populus alba L. x P. grandidentata Michx. 'Crandon') were studied. To investigate multiple shoot regeneration capacity of different cells, tissues, and ...


Relaxin And Progesterone Secretion From Aging Corpora Lutea And Relaxin's Action On The Uterine Cervix Of The Pig , Chang-Jiang Huang Jan 1991

Relaxin And Progesterone Secretion From Aging Corpora Lutea And Relaxin's Action On The Uterine Cervix Of The Pig , Chang-Jiang Huang

Retrospective Theses and Dissertations

Relaxin and progesterone are produced in the corpora lutea of the pig. In hysterectomized gilts, insulin-like growth factor I, luteinizing hormone; and prolactin alone or in combination increase progesterone production by aging luteal tissue from day 110 post-estrus, but they are ineffective at days 113 and 116. In contrast, the same hormone treatments increase relaxin production by these luteal tissues from days 110 and 113 compared with those tissues from the animals on day 116. Insulin-like growth factor I augments the ability of luteinizing hormone and prolactin to increase progesterone and relaxin production by aging corpora lutea;The primary physiological ...


Characterization Of The Mitogen Regulated Protein Receptor , Joseph T. Nelson Jan 1991

Characterization Of The Mitogen Regulated Protein Receptor , Joseph T. Nelson

Retrospective Theses and Dissertations

Mitogen regulated protein (MRP) is a glycoprotein synthesized in murine placenta and secreted into the maternal bloodstream during gestation. The temporal profile of MRP concentration in the plasma during gestation, its synthesis in an organ known to secrete other lactogenic hormones, and its homology to prolactin suggest an hormonal role;A requisite characteristic of a polypeptide hormone is to have a receptor on the plasma membrane of another tissue separate from its site of synthesis. The receptor then mediates the functional effects by binding the hormone. I discovered and characterized a receptor for MRP from murine uterine membrane preparations. The ...


Infected Cell Types In The Ovine Lung Following Exposure To Bovine Respiratory Syncytial Virus , James Toby Meehan Jan 1991

Infected Cell Types In The Ovine Lung Following Exposure To Bovine Respiratory Syncytial Virus , James Toby Meehan

Retrospective Theses and Dissertations

Immunohistochemical and lung organ culture techniques were developed and used to detect bovine respiratory syncytial virus-infected cell types in ovine lung tissue. Lung tissue was evaluated from sheep inoculated with bovine respiratory syncytial virus (BRSV) and from lung organ slices inoculated with BRSV in vitro. Infected sheep were killed at intervals from 0.5 to 8 days post-inoculation. Histological changes consisted of bronchiolitis, interstitial pneumonitis and pneumonia with exudates of neutrophils, lymphocytes and macrophages. Interstitial infiltrates consisted of peribronchiolar and perivascular lymphocytes and macrophages which extended into alveolar septa. Foci of infection were very sparse as determined by immunohistochemistry. Bovine ...


Cloning And Immunogenicity Of A Chlamydia Trachomatis 36 Kilodalton Recombinant Gene Product In Escherichia Coli, Hector Rivera Jan 1991

Cloning And Immunogenicity Of A Chlamydia Trachomatis 36 Kilodalton Recombinant Gene Product In Escherichia Coli, Hector Rivera

Theses Digitization Project

No abstract provided.


Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe Jan 1991

Cell Surface-Binding Sites For Progesterone Mediate Calcium Uptake In Human Sperm, Peter F. Blackmore, Joseph Neulan, Frank Lattanzio, Stephen J. Beebe

Bioelectrics Publications

Recent studies (e.g. Blackmore, P. F., Beebe, S. J., Danforth, D. R., and Alexander, N.) (1990) J. Biol. Chem. 265, 1376-1380) have shown that in human sperm, progesterone produces a rapid increase in intracellular free calcium ([Ca2+]i) and an induction of the acrosome reaction (e.g. Osman, R. A., Andria, M. L., Jones, A. D., and Meizel, S. (1989) Biochem. Biophys. Res. Commun. 160, 828-833). In this study, the location of progesterone receptors on the cell surface of human sperm was identified using progesterone immobilized on bovine serum albumin (BSA) (progesterone 3-(O-carboxymethyl)oxime:BSA) as well as ...