Open Access. Powered by Scholars. Published by Universities.®

Medical Cell Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1861 - 1890 of 1927

Full-Text Articles in Medical Cell Biology

Auto-Inhibition Of Ets-1 Is Counteracted By Dna Binding Cooperativity With Core-Binding Factor Α2, Tamara L. Goetz, Ting-Lei Gu, Nancy A. Speck, Barbara J. Graves Jan 2000

Auto-Inhibition Of Ets-1 Is Counteracted By Dna Binding Cooperativity With Core-Binding Factor Α2, Tamara L. Goetz, Ting-Lei Gu, Nancy A. Speck, Barbara J. Graves

Dartmouth Scholarship

Auto-inhibition is a common transcriptional control mechanism that is well characterized in the regulatory transcription factor Ets-1. Autoinhibition of Ets-1 DNA binding works through an inhibitory module that exists in two conformations. DNA binding requires a change in the inhibitory module from the packed to disrupted conformation. This structural switch provides a mechanism to tightly regulate Ets-1 DNA binding. We report that the Ets-1 partner protein core-binding factor α2 (CBFα2; also known as AML1 or PEBP2) stimulates Ets-1 DNA binding and counteracts auto-inhibition. Support for this conclusion came from three observations. First, the level of cooperative DNA binding (10-fold) was …

Go to article

A Ligand Binding Domain Mutation In The Mouse Glucocorticoid Receptor Functionally Links Chromatin Remodeling And Transcription Initiation, Lynn A. Sheldon, Catharine L. Smith, Jack E. Bodwell, Allan U. Munck, Gordon L. Hager Dec 1999

A Ligand Binding Domain Mutation In The Mouse Glucocorticoid Receptor Functionally Links Chromatin Remodeling And Transcription Initiation, Lynn A. Sheldon, Catharine L. Smith, Jack E. Bodwell, Allan U. Munck, Gordon L. Hager

Dartmouth Scholarship

We utilized the mouse mammary tumor virus (MMTV) long terminal repeat (LTR) in vivo to understand how the interaction of the glucocorticoid receptor (GR) with a nucleosome-assembled promoter allows access of factors required for the transition from a repressed promoter to a derepressed, transcriptionally competent promoter. A mutation (C644G) in the ligand binding domain (LBD) of the mouse GR has provided information regarding the steps required in the derepression/activation process and in the functional significance of the two major transcriptional activation domains, AF1 and AF2. The mutant GR activates transcription from a transiently transfected promoter that has a disordered nucleosomal …

Go to article

Three V-Snares And Two T-Snares, Present In A Pentameric Cis-Snare Complex On Isolated Vacuoles, Are Essential For Homotypic Fusion, Christian Ungermann, Gabriele F. Von Mollard, Ole N. Jensen, Nathan Margolis, Tom H. Stevens, William Wickner Jun 1999

Three V-Snares And Two T-Snares, Present In A Pentameric Cis-Snare Complex On Isolated Vacuoles, Are Essential For Homotypic Fusion, Christian Ungermann, Gabriele F. Von Mollard, Ole N. Jensen, Nathan Margolis, Tom H. Stevens, William Wickner

Dartmouth Scholarship

Vacuole SNAREs, including the t-SNAREs Vam3p and Vam7p and the v-SNARE Nyv1p, are found in a multisubunit "cis" complex on isolated organelles. We now identify the v-SNAREs Vti1p and Ykt6p by mass spectrometry as additional components of the immunoisolated vacuolar SNARE complex. Immunodepletion of detergent extracts with anti-Vti1p removes all the Ykt6p that is in a complex with Vam3p, immunodepletion with anti-Ykt6p removes all the Vti1p that is complexed with Vam3p, and immunodepletion with anti-Nyv1p removes all the Ykt6p in complex with other SNAREs, demonstrating that they are all together in the same cis multi-SNARE complex. After priming, which disassembles …

Go to article

Interaction Between Fgf And Bmp Signaling Pathways Regulates Development Of Metanephric Mesenchyme., Andrew T. Dudley, R. E. Godin, E. J. Robertson Jun 1999

Interaction Between Fgf And Bmp Signaling Pathways Regulates Development Of Metanephric Mesenchyme., Andrew T. Dudley, R. E. Godin, E. J. Robertson

Journal Articles: Genetics, Cell Biology & Anatomy

Nephrogenesis in the mouse kidney begins at embryonic day 11 and ends approximately 10 days postpartum. During this period, new nephrons are continually being generated from a stem-cell population-the nephrogenic mesenchyme-in response to signals emanating from the tips of the branching ureter. Relatively little is known about the mechanism by which the nephrogenic mesenchyme cell population is maintained at the tips of the ureter in the presence of signals promoting tubulogenesis. Previous studies have shown that a loss of Bmp7 function leads to kidney defects that are a likely result of progressive loss of nephrogenic mesenchyme by apoptosis. The studies …

Go to article

Characterizing Erythrocyte Motions In Flowing Blood, Markos Leggas Jun 1999

Characterizing Erythrocyte Motions In Flowing Blood, Markos Leggas

Theses and Dissertations (ETD)

Characterizing the probabilistic motions of cells is a prerequisite for the development of a general model of transport and surface deposition of white cells and platelets (WBC/P). These phenomena differ greatly when red blood cells (RBC) are present at normal levels, but follow convective diffusion in dilute suspensions. A critical need is to understand and characterize dispersion and diffusion as they apply to red cells in suspension flow. The dispersive motions of
0.5-micrometer beads and fluorescently labeled human RBC flowing in dilute (0.003%) and concentrated (25%) RBC suspensions, respectively, were characterized using fluorescence videomicroscopy methods, and times for individual tracer …

Go to article

Staphylococcal Enterotoxin B Primes Cytokine Secretion And Lytic Activity In Response To Native Bacterial Antigens, K. M. Mason, T. D. Dryden, Nancy J. Bigley, P. S. Fink Nov 1998

Staphylococcal Enterotoxin B Primes Cytokine Secretion And Lytic Activity In Response To Native Bacterial Antigens, K. M. Mason, T. D. Dryden, Nancy J. Bigley, P. S. Fink

Neuroscience, Cell Biology & Physiology Faculty Publications

Superantigens stimulate T-lymphocyte proliferation and cytokine production, but the effects of superantigen exposure on cell function within a complex, highly regulated immune response remain to be determined. In this study, we demonstrate that superantigen exposure significantly alters the murine host response to bacterial antigens in an in vitro coculture system. Two days after exposure to the superantigen staphylococcal enterotoxin B, splenocytes cultured with Streptococcus mutans produced significantly greater amounts of gamma interferon (IFN-gamma) and interleukin-12 than did sham-injected controls. The majority of IFN-gamma production appeared to be CD8(+) T-cell derived since depletion of this cell type dramatically reduced the levels …

Go to article

Identifying Swelling-Activated Channels From Ion Selectivity Patterns, Dan R. Halm Sep 1998

Identifying Swelling-Activated Channels From Ion Selectivity Patterns, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

No abstract provided.

Go to article

Subcellular Localization Of Mineralocorticoid Receptors In Living Cells: Effects Of Receptor Agonists And Antagonists, Géza Fejes-Tóth, David Pearce, Anikó Náray-Fejes-Tóth Mar 1998

Subcellular Localization Of Mineralocorticoid Receptors In Living Cells: Effects Of Receptor Agonists And Antagonists, Géza Fejes-Tóth, David Pearce, Anikó Náray-Fejes-Tóth

Dartmouth Scholarship

Results on the subcellular localization of the mineralocorticoid receptor (MR) have been controversial. To determine the subcellular distribution and trafficking of the MR in living cells after binding of agonists and antagonists, we expressed a MR-green fluorescent protein (GFP) chimera in mammalian cells lacking endogenous MR. The GFP-tagged MR (GFP-MR) remained transcriptionally active, as determined in cotransfection experiments with the MR-responsive reporter, TAT3-LUC. The subcellular localization of GFP-MR was monitored by fluorescence time-lapse microscopy. In the absence of hormone, MR was present both in the cytoplasm and nucleus. Aldosterone induced a rapid nuclear accumulation of the MR. Aldosterone-bound GFP-MR was …

Go to article

A Vacuolar V–T-Snare Complex, The Predominant Form In Vivo And On Isolated Vacuoles, Is Disassembled And Activated For Docking And Fusion, Christian Ungermann, Benjamin J. Nichols, Hugh R. B. Pelham, William Wickner Jan 1998

A Vacuolar V–T-Snare Complex, The Predominant Form In Vivo And On Isolated Vacuoles, Is Disassembled And Activated For Docking And Fusion, Christian Ungermann, Benjamin J. Nichols, Hugh R. B. Pelham, William Wickner

Dartmouth Scholarship

Homotypic vacuole fusion in yeast requires Sec18p (N-ethylmaleimide-sensitive fusion protein [NSF]), Sec17p (soluble NSF attachment protein [alpha-SNAP]), and typical vesicle (v) and target membrane (t) SNAP receptors (SNAREs). We now report that vacuolar v- and t-SNAREs are mainly found with Sec17p as v-t-SNARE complexes in vivo and on purified vacuoles rather than only transiently forming such complexes during docking, and disrupting them upon fusion. In the priming reaction, Sec18p and ATP dissociate this v-t-SNARE complex, accompanied by the release of Sec17p. SNARE complex structure governs each functional aspect of priming, as the v-SNARE regulates the rate of Sec17p release and, …

Go to article

Characterization Of The Promoter And Upstream Activation Sequences Of Sporulation-Specific Genes Spr1 (Ssg1) And Spr2 In Saccharomyces Cerevisiae, Sharmini S. Soosaithasan Jan 1998

Characterization Of The Promoter And Upstream Activation Sequences Of Sporulation-Specific Genes Spr1 (Ssg1) And Spr2 In Saccharomyces Cerevisiae, Sharmini S. Soosaithasan

Theses, Dissertations and Capstones

Sporulation is a developmental process in which temporally distinct sets of genes regulate the processes of meiosis and ascospore formation. Sporulation-specific genes are classified into early, middle, and late genes based on their peak time of expression during sporulation. Regulation of two late genes, SPR1 and SPR2, was studied. The function of SPR2 is unknown. Its regulatory region contains two Mid Sporulation Elements (MSE) repeated in tandem that are sufficient to confer sporulation-specific regulation to a CYCl-lacZ reporter. These sequences have UAS (upstream activation sequence) properties, as each 14 base pair element is sufficient to confer sporulation-specific regulation …

Go to article

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers Dec 1997

Direct Demonstration Of Retroviral Recombination In A Rhesus Monkey, Dawn P. Wooley, Randall A. Smith, Susan Czajak, Ronald C. Desrosiers

Neuroscience, Cell Biology & Physiology Faculty Publications

Recombination may be an important mechanism for increasing variation in retroviral populations. Retroviral recombination has been demonstrated in tissue culture systems by artificially creating doubly infected cells. Evidence for retroviral recombination in vivo is indirect and is based principally on the identification of apparently mosaic human immunodeficiency virus type 1 genomes from phylogenetic analyses of viral sequences. We infected a rhesus monkey with two different molecularly cloned strains of simian immunodeficiency virus. One strain of virus had a deletion in vpx and vpr, and the other strain had a deletion in nef. Each strain on its own induced low virus …

Go to article

Mitotic Spindle Poles Are Organized By Structural And Motor Proteins In Addition To Centrosomes, Tirso Gaglio, Mary A. Dionne, Duane A. Duane A. Compton Sep 1997

Mitotic Spindle Poles Are Organized By Structural And Motor Proteins In Addition To Centrosomes, Tirso Gaglio, Mary A. Dionne, Duane A. Duane A. Compton

Dartmouth Scholarship

The focusing of microtubules into mitotic spindle poles in vertebrate somatic cells has been assumed to be the consequence of their nucleation from centrosomes. Contrary to this simple view, in this article we show that an antibody recognizing the light intermediate chain of cytoplasmic dynein (70.1) disrupts both the focused organization of microtubule minus ends and the localization of the nuclear mitotic apparatus protein at spindle poles when injected into cultured cells during metaphase, despite the presence of centrosomes. Examination of the effects of this dynein-specific antibody both in vitro using a cell-free system for mitotic aster assembly and in …

Go to article

Sqt1, Which Encodes An Essential Wd Domain Protein Of Saccharomyces Cerevisiae, Suppresses Dominant-Negative Mutations Of The Ribosomal Protein Gene Qsr1., Dominic P. Eisinger, Frederick A. Dick, Elke Denke, Bernard L. Trumpower Sep 1997

Sqt1, Which Encodes An Essential Wd Domain Protein Of Saccharomyces Cerevisiae, Suppresses Dominant-Negative Mutations Of The Ribosomal Protein Gene Qsr1., Dominic P. Eisinger, Frederick A. Dick, Elke Denke, Bernard L. Trumpower

Dartmouth Scholarship

QSR1 is an essential Saccharomyces cerevisiae gene, which encodes a 60S ribosomal subunit protein required for joining of 40S and 60S subunits. Truncations of QSR1 predicted to encode C-terminally truncated forms of Qsr1p do not substitute for QSR1 but do act as dominant negative mutations, inhibiting the growth of yeast when expressed from an inducible promoter. The dominant negative mutants exhibit a polysome profile characterized by 'half-mer' polysomes, indicative of a subunit joining defect like that seen in other qsr1 mutants (D. P. Eisinger, F. A. Dick, and B. L. Trumpower, Mol. Cell. Biol. 17:5136-5145, 1997.) By screening a high-copy …

Go to article

Qsr1p, A 60s Ribosomal Subunit Protein, Is Required For Joining Of 40s And 60s Subunits., Dominic P. Eisinger, Frederick A. Dick, Bernard L. Trumpower Sep 1997

Qsr1p, A 60s Ribosomal Subunit Protein, Is Required For Joining Of 40s And 60s Subunits., Dominic P. Eisinger, Frederick A. Dick, Bernard L. Trumpower

Dartmouth Scholarship

QSR1 is a recently discovered, essential Saccharomyces cerevisiae gene, which encodes a 60S ribosomal subunit protein. Thirty-one unique temperature-sensitive alleles of QSR1 were generated by regional codon randomization within a conserved 20-amino-acid sequence of the QSR1-encoded protein. The temperature-sensitive mutants arrest as viable, large, unbudded cells 24 to 48 h after a shift to 37 degrees C. Polysome and ribosomal subunit analysis by velocity gradient centrifugation of lysates from temperature-sensitive qsr1 mutants and from cells in which Qsr1p was depleted by down regulation of an inducible promoter revealed the presence of half-mer polysomes and a large pool of free 60S …

Go to article

Assembly And Regulation Of The Cd40 Receptor Complex In Human B Cells, Michelle R. Kuhné, Michael Robbins, John E. Hambor, Matthew F. Mackey, Yoko Kosaka, Toshihide Nishimura, Jason P. Gigley, Randolph J. Noelle, David M. Calderhead Jul 1997

Assembly And Regulation Of The Cd40 Receptor Complex In Human B Cells, Michelle R. Kuhné, Michael Robbins, John E. Hambor, Matthew F. Mackey, Yoko Kosaka, Toshihide Nishimura, Jason P. Gigley, Randolph J. Noelle, David M. Calderhead

Dartmouth Scholarship

CD40 is a member of the tumor necrosis factor (TNF) receptor superfamily. Studies with human B cells show that the binding of CD154 (gp39, CD40L) to CD40 recruits TNF receptor– associated factor 2 (TRAF2) and TRAF3 to the receptor complex, induces the downregulation of the nonreceptor-associated TRAFs in the cell and induces an increased expression of Fas on the cell surface. Combined signaling through the interluekin 4 receptor and CD40 induces an increased expression of Fas with a commensurate increase in the level of TRAF2, but not TRAF3, that is recruited to the receptor complex. In contrast, engagement of the …

Go to article

The Glucose Transporter Glut4 And The Aminopeptidase Vp165 Colocalise In Tubulo-Vesicular Elements In Adipocytes And Cardiomyocytes, Sally Martin, Jacqueline E. Rice, Gwyn W. Gould, Susanna R. Keller Jun 1997

The Glucose Transporter Glut4 And The Aminopeptidase Vp165 Colocalise In Tubulo-Vesicular Elements In Adipocytes And Cardiomyocytes, Sally Martin, Jacqueline E. Rice, Gwyn W. Gould, Susanna R. Keller

Dartmouth Scholarship

The aminopeptidase vp165 is one of the major polypeptides enriched in GLUT4-containing vesicles immuno-isolated from adipocytes. In the present study we have confirmed and quantified the high degree of colocalisation between GLUT4 and vp165 using double label immuno-electron microscopy on vesicles isolated from adipocytes and heart. The percentage of vp165-containing vesicles that also contained GLUT4 was 91%, 76%, and 86% in rat adipocytes, 3T3-L1 adipocytes, and rat heart, respectively. Internalisation of a transferrin/HRP (Tf/HRP) conjugate by 3T3-L1 adipocytes, followed by diaminobenzidine treatment in intact cells, resulted in ablation of only 41% and 45% of GLUT4 and vp165, respectively, whereas endosomal …

Go to article

Identification Of A Novel Antiapoptotic Functional Domain In Simian Virus 40 Large T Antigen., Suzanne D. Conzen, Christine A. Snay, Charles N. Cole Jun 1997

Identification Of A Novel Antiapoptotic Functional Domain In Simian Virus 40 Large T Antigen., Suzanne D. Conzen, Christine A. Snay, Charles N. Cole

Dartmouth Scholarship

The ability of DNA tumor virus proteins to trigger apoptosis in mammalian cells is well established. For example, transgenic expression of a simian virus 40 (SV40) T-antigen N-terminal fragment (N-termTag) is known to induce apoptosis in choroid plexus epithelial cells. SV40 T-antigen-induced apoptosis has generally been considered to be a p53-dependent event because cell death in the brain is greatly diminished in a p53-/- background strain and is abrogated by expression of wild-type (p53-binding) SV40 T antigen. We now show that while N-termTags triggered apoptosis in rat embryo fibroblasts cultured in low serum, expression of full-length T antigens unable to …

Go to article

C-Terminal Truncations Of The Yeast Nucleoporin Nup145p Produce A Rapid Temperature-Conditional Mrna Export Defect And Alterations To Nuclear Structure., Thomas C. Dockendorff, Catherine V. Heath, Alan L. Goldstein, Christine A. Snay, C N. Cole Feb 1997

C-Terminal Truncations Of The Yeast Nucleoporin Nup145p Produce A Rapid Temperature-Conditional Mrna Export Defect And Alterations To Nuclear Structure., Thomas C. Dockendorff, Catherine V. Heath, Alan L. Goldstein, Christine A. Snay, C N. Cole

Dartmouth Scholarship

A screen for temperature-sensitive mutants of Saccharomyces cerevisiae defective in nucleocytoplasmic trafficking of poly(A)+ RNA has identified an allele of the NUP145 gene, which encodes an essential nucleoporin. NUP145 was previously identified by using a genetic synthetic lethal screen (E. Fabre, W. C. Boelens, C. Wimmer, I. W. Mattaj, and E. C. Hurt, Cell 78:275-289, 1994) and by using a monoclonal antibody which recognizes the GLFG family of vertebrate and yeast nucleoporins (S. R. Wente and G. Blobel, J. Cell Biol. 125:955-969, 1994). Cells carrying the new allele, nup145-10, grew at 23 and 30 degrees C but were unable to …

Go to article

Analysis Of Mutant Platelet-Derived Growth Factor Receptors Expressed In Pc12 Cells Identifies Signals Governing Sodium Channel Induction During Neuronal Differentiation., Gary R. Fanger, Richard R. Vaillancourt, Lynn E. Heasley, Jean-Pierre P. Montmayeur, Gary L. Johnson, Robert A. Maue Jan 1997

Analysis Of Mutant Platelet-Derived Growth Factor Receptors Expressed In Pc12 Cells Identifies Signals Governing Sodium Channel Induction During Neuronal Differentiation., Gary R. Fanger, Richard R. Vaillancourt, Lynn E. Heasley, Jean-Pierre P. Montmayeur, Gary L. Johnson, Robert A. Maue

Dartmouth Scholarship

The mechanisms governing neuronal differentiation, including the signals underlying the induction of voltage-dependent sodium (Na+) channel expression by neurotrophic factors, which occurs independent of Ras activity, are not well understood. Therefore, Na+ channel induction was analyzed in sublines of PC12 cells stably expressing platelet-derived growth factor (PDGF) beta receptors with mutations that eliminate activation of specific signalling molecules. Mutations eliminating activation of phosphatidylinositol 3-kinase (PI3K), phospholipase C gamma (PLC gamma), the GTPase-activating protein (GAP), and Syp phosphatase failed to diminish the induction of type II Na+ channel alpha-subunit mRNA and functional Na+ channel expression by PDGF, as determined by RNase …

Go to article

The Role Of Fas And Fas Ligand In Apoptosis During Regression Of The Corpus Luteum, Sharon Roughton Jan 1997

The Role Of Fas And Fas Ligand In Apoptosis During Regression Of The Corpus Luteum, Sharon Roughton

Theses : Honours

Apoptosis, a form of physiological cell death, has been found to occur during regression of the corpus luteum (Juengel etal, 1993; Dharmarajan etal, 1994). The pathways involved in this process, however, have yet to be specified. One possible mediator of corpus luteum regression is the Fas (or AP0-1 or CD95) receptor, a transmembrane protein which induces apoptosis in the cell when ligated. In order to further confirm this hypolhesis, the present study establishes and quantitates the presence and regulation of Fas receptor and Fas ligand (Fasl) in the rat corpus luteum during pregnancy and post-partum. The animals used were sexually …

Go to article

A Recombinant Inwardly Rectifying Potassium Channel Coupled To Gtp-Binding Proteins, Kim W. Chan, M. Noelle Langan, Jin Liang Sui, J. Ashot Kozak, Amanda Pabon, John A. A. Ladias, Diomedes E. Logothetis Mar 1996

A Recombinant Inwardly Rectifying Potassium Channel Coupled To Gtp-Binding Proteins, Kim W. Chan, M. Noelle Langan, Jin Liang Sui, J. Ashot Kozak, Amanda Pabon, John A. A. Ladias, Diomedes E. Logothetis

Neuroscience, Cell Biology & Physiology Faculty Publications

GTP-binding (G) proteins have been shown to mediate activation of inwardly rectifying potassium (K+) channels in cardiac, neuronal and neuroendocrine cells. Here, we report functional expression of a recombinant inwardly rectifying channel which we call KGP (or hpKir3.4), to signify that it is K+ selective, G-protein-gated and isolated from human pancreas. KGP expression in Xenopus oocytes resulted in sizeable basal (or agonist-independent) currents while coexpression with a G-protein-linked receptor, yielded additional agonist-induced currents. Coexpression of KGP and hGIRK1 (a human brain homolog of GIRK1/Kir3.1) produced much larger basal currents than those observed with KGP or hGIRK1 alone, and upon coexpression …

Go to article

Antisense Oligodeoxynucleotide Inhibition Of A Swelling-Activated Cation Channel In Osteoblast-Like Osteosarcoma Cells., Randall L. Duncan, Neil Kizer, Elizabeth L. Barry, Peter P A Friedman, Keith A. Hruska Mar 1996

Antisense Oligodeoxynucleotide Inhibition Of A Swelling-Activated Cation Channel In Osteoblast-Like Osteosarcoma Cells., Randall L. Duncan, Neil Kizer, Elizabeth L. Barry, Peter P A Friedman, Keith A. Hruska

Dartmouth Scholarship

By patch-clamp analysis, we have shown that chronic, intermittent mechanical strain (CMS) increases the activity of stretch-activated cation channels of osteoblast-like UMR-106.01 cells. CMS also produces a swelling-activated whole-cell conductance (Gm) regulated by varying strain levels. We questioned whether the swelling-activated conductance was produced by stretch-activated cation channel activity. We have identified a gene involved in the increase in conductance by using antisense oligodeoxynucleotides (ODN) derived from the alpha 1-subunit genes of calcium channels found in UMR-106.01 cells (alpha1S, alpha1C, and alpha1D). We demonstrate that alpha 1C antisense ODNs abolish the increase in Gm in response to hypotonic swelling following …

Go to article

Distinct Cis-Acting Elements Mediate Clock, Light, And Developmental Regulation Of The Neurospora Crassa Eas (Ccg-2) Gene., Deborah Bell-Pedersen, Jay C. Dunlap, Jennifer J. Loros Feb 1996

Distinct Cis-Acting Elements Mediate Clock, Light, And Developmental Regulation Of The Neurospora Crassa Eas (Ccg-2) Gene., Deborah Bell-Pedersen, Jay C. Dunlap, Jennifer J. Loros

Dartmouth Scholarship

The Neurospora crassa eas (ccg-2) gene, which encodes a fungal hydrophobin, is transcriptionally regulated by the circadian clock. In addition, eas (ccg-2) is positively regulated by light and transcripts accumulate during asexual development. To sort out the basis of this complex regulation, deletion analyses of the eas (ccg-2) promoter were carried out to localize the cis-acting elements mediating clock, light, and developmental control. The primary sequence determinants of a positive activating clock element (ACE) were found to reside in a 45-bp region, just upstream from the TATA box. Using a novel unregulated promoter/reporter system developed for this study, we show …

Go to article

Gtpase-Deficient G Alpha 16 And G Alpha Q Induce Pc12 Cell Differentiation And Persistent Activation Of Cjun Nh2-Terminal Kinases., Lynn E. Heasley, Brooke Storey, Gary R. Fanger, Laura Butterfield, J Zamarripa, D Blumberg, R A. Maue Feb 1996

Gtpase-Deficient G Alpha 16 And G Alpha Q Induce Pc12 Cell Differentiation And Persistent Activation Of Cjun Nh2-Terminal Kinases., Lynn E. Heasley, Brooke Storey, Gary R. Fanger, Laura Butterfield, J Zamarripa, D Blumberg, R A. Maue

Dartmouth Scholarship

Persistent stimulation of specific protein kinase pathways has been proposed as a key feature of receptor tyrosine kinases and intracellular oncoproteins that signal neuronal differentiation of rat pheochromocytoma (PC12) cells. Among the protein serine/threonine kinases identified to date, the p42/44 mitogen-activated protein (MAP) kinases have been highlighted for their potential role in signalling PC12 cell differentiation. We report here that retrovirus-mediated expression of GTPase-deficient, constitutively active forms of the heterotrimeric Gq family members, G alpha qQ209L and G alpha 16Q212L, in PC12 cells induces neuronal differentiation as indicated by neurite outgrowth and the increased expression of voltage-dependent sodium channels. Differentiation …

Go to article

The Effect Of Estrogen In A Murine Model Of Peritoneal Adhesion Formation, Michelle Rene Frazier-Jessen Jan 1996

The Effect Of Estrogen In A Murine Model Of Peritoneal Adhesion Formation, Michelle Rene Frazier-Jessen

Dissertations

No abstract provided.

Go to article

Gas1-Induced Growth Suppression Requires A Transactivation-Independent P53 Function., Giannino Del Sal, Elisabetta M. Ruaro, Rene Utrera, Charles N. Cole Dec 1995

Gas1-Induced Growth Suppression Requires A Transactivation-Independent P53 Function., Giannino Del Sal, Elisabetta M. Ruaro, Rene Utrera, Charles N. Cole

Dartmouth Scholarship

In normal cells, induction of quiescence is accompanied by the increased expression of growth arrest-specific genes (gas). One of them, gas1, is regulated at the transcriptional level and codes for a membrane-associated protein (Gas1) which is down regulated during the G0-to-S phase transition in serum-stimulated cells. Gas1 is not expressed in growing or transformed cells, and when overexpressed in normal fibroblasts, it blocks the G0-to-S phase transition. Moreover, Gas1 blocks cell proliferation in several transformed cells with the exception of simian virus 40- or adenovirus-transformed cell lines. In this paper, we demonstrate that overexpression of Gas1 blocks cell proliferation in …

Go to article

A Requirement For Bone Morphogenetic Protein-7 During Development Of The Mammalian Kidney And Eye., Andrew T. Dudley, K. M. Lyons, E. J. Robertson Nov 1995

A Requirement For Bone Morphogenetic Protein-7 During Development Of The Mammalian Kidney And Eye., Andrew T. Dudley, K. M. Lyons, E. J. Robertson

Journal Articles: Genetics, Cell Biology & Anatomy

BMP-7/OP-1, a member of the transforming growth factor-beta (TGF-beta) family of secreted growth factors, is expressed during mouse embryogenesis in a pattern suggesting potential roles in a variety of inductive tissue interactions. The present study demonstrates that mice lacking BMP-7 display severe defects confined to the developing kidney and eye. Surprisingly, the early inductive tissue interactions responsible for establishing both organs appear largely unaffected. However, the absence of BMP-7 disrupts the subsequent cellular interactions required for their continued growth and development. Consequently, homozygous mutant animals exhibit renal dysplasia and anophthalmia at birth. Overall, these findings identify BMP-7 as an essential …

Go to article

Transactivation Of The Moloney Murine Leukemia Virus And T-Cell Receptor Beta-Chain Enhancers By Cbf And Ets Requires Intact Binding Sites For Both Proteins., Wanwen Sun, Barbara J. Graves, Nancy A. Speck Aug 1995

Transactivation Of The Moloney Murine Leukemia Virus And T-Cell Receptor Beta-Chain Enhancers By Cbf And Ets Requires Intact Binding Sites For Both Proteins., Wanwen Sun, Barbara J. Graves, Nancy A. Speck

Dartmouth Scholarship

The Moloney murine leukemia virus (Mo-MLV) enhancer contains binding sites (LVb and LVc) for the ets gene family of proteins and a core site that binds the polyomavirus enhancer-binding protein 2/core-binding factor (cbf) family of proteins. The LVb and core sites in the Mo-MLV enhancer contribute to its constitutive activity in T cells. All three binding sites (LVb, LVc, and core) are required for phorbol ester inducibility of the Mo-MLV enhancer. Adjacent binding sites for the ets and cbf proteins likewise constitute a phorbol ester response element within the human T-cell receptor beta-chain (TCR beta) enhancer and contribute to constitutive …

Go to article

Increased Abundance Of The Receptor-Type Protein-Tyrosine Phosphatase Lar Accounts For The Elevated Insulin Receptor Dephosphorylating Activity In Adipose Tissue Of Obese Human Subjects, Falyaz Ahmad, Robert V. Considine, Barry J. Goldstein Jun 1995

Increased Abundance Of The Receptor-Type Protein-Tyrosine Phosphatase Lar Accounts For The Elevated Insulin Receptor Dephosphorylating Activity In Adipose Tissue Of Obese Human Subjects, Falyaz Ahmad, Robert V. Considine, Barry J. Goldstein

Department of Medicine Faculty Papers

Protein-tyrosine phosphatases (PTPases) have an essential role in the regulation of the steady-state phosphorylation of the insulin receptor and other proteins in the insulin signalling pathway. To examine whether increased PTPase activity is associated with adipose tissue insulin resistance in human obesity we measured PTPase enzyme activity towards the insulin receptor in homogenates of subcutaneous adipose tissue from a series of six lean and six nondiabetic, obese (body mass index > 30) subjects. The obese subjects had a mean 1.74-fold increase in PTPase activity (P < 0.0001) with a striking positive correlation by linear regression analysis between PTPase activity and body mass index among all of the samples (R = 0.918; P < 0.0001). The abundance of three candidate insulin receptor PTPases in adipose tissue was also estimated by immunoblot analysis. The most prominent increase was a 2.03-fold rise in the transmembrane PTPase LAR (P < 0.001). Of the three PTPase examined, only immunodepletion of LAR protein from the homogenates with neutralizing antibodies resulted in normalization of the PTPase activity towards the insulin receptor, demonstrating that the increase in LAR was responsible for the enhanced PTPase activity in the adipose tissue from obese subjects. These studies suggest that increased PTPase activity towards the insulin receptor is a pathogenetic factor in the insulin resistance of adipose tissue in human obesity and provide evidence for a potential role of the LAR PTPase in the regulation of insulin signalling in disease states.

Go to article

The Gtp-Bound Form Of The Yeast Ran/Tc4 Homologue Blocks Nuclear Protein Import And Appearance Of Poly(A)+ Rna In The Cytoplasm., Gabriel Schlenstedt, Claudio Saavedra, Jonathan D. Loeb, Charles N. Cole, Pamela A. Silver Jan 1995

The Gtp-Bound Form Of The Yeast Ran/Tc4 Homologue Blocks Nuclear Protein Import And Appearance Of Poly(A)+ Rna In The Cytoplasm., Gabriel Schlenstedt, Claudio Saavedra, Jonathan D. Loeb, Charles N. Cole, Pamela A. Silver

Dartmouth Scholarship

Ran/TC4, a Ras-like GTP-binding protein, and its nucleotide exchanger, RCC1, have been implicated in control of protein movement into the nucleus and cytoplasmic accumulation of mRNA. Saccharomyces cerevisiae contains two homologues of the mammalian Ran/TC4, encoded by the GSP1 and GSP2 genes. We have constructed yeast strains that overproduce either wild-type Gsp1 or a form of Gsp1 with glycine-21 converted to valine (Gsp1-G21V), which we show stabilizes the GTP-bound form. Cells producing Gsp1-G21V have defects in localization of nuclear proteins; nuclear proteins accumulate in the cytoplasm following galactose induction of Gsp1-G21V. Similarly, cells producing Gsp1-G21V retain poly(A)+ RNA in their …

Go to article

First Prev Next Last