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Articles 61 - 84 of 84

Full-Text Articles in Medical Cell Biology

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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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Cooperative Binding Of Ets-1 And Core Binding Factor To Dna., David Wotton, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen Jan 1994

Cooperative Binding Of Ets-1 And Core Binding Factor To Dna., David Wotton, Jacques Ghysdael, Shuwen Wang, Nancy A. Speck, Michael J. Owen

Dartmouth Scholarship

Two phorbol ester-inducible elements (beta E2 and beta E3) within the human T-cell receptor beta gene enhancer each contain consensus binding sites for the Ets and core binding factor (CBF) transcription factor families. Recombinant Ets-1 and purified CBF bound individually to beta E2 and beta E3, in which the Ets and core sites are directly adjacent. In this report, we show that CBF and Ets-1 bind together to beta E2 and beta E3 and that Ets-1-CBF-DNA complexes are favored over the binding of either protein alone to beta E2. Formation of Ets-1-CBF-DNA complexes increased the affinity of Ets-1-DNA interactions and …

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Use Of Yeast Artificial Chromosomes (Yacs) For Studying Control Of Gene Expression: Correct Regulation Of The Genes Of A Human Beta-Globin Locus Yac Following Transfer To Mouse Erythroleukemia Cell Lines., Kenneth Peterson, Galynn Zitnik, Clare Huxley, Christopher Lowrey Dec 1993

Use Of Yeast Artificial Chromosomes (Yacs) For Studying Control Of Gene Expression: Correct Regulation Of The Genes Of A Human Beta-Globin Locus Yac Following Transfer To Mouse Erythroleukemia Cell Lines., Kenneth Peterson, Galynn Zitnik, Clare Huxley, Christopher Lowrey

Dartmouth Scholarship

We demonstrate that transfer of a yeast artificial chromosome (YAC) containing 230 kb of the human beta-globin locus into mouse erythroleukemia cells by fusion results in correct developmental regulation of the human beta-like globin genes. Additionally, we show that early after hybrid formation, human embryonic epsilon- and fetal gamma-globin genes are coexpressed with the adult beta gene but that after 10-20 weeks in culture, globin gene expression switches to predominantly adult. Thus, in contrast to shorter gene constructs, the globin genes of the beta-globin locus YAC are regulated like the chromosomal globin genes. These results indicate that transfer of YACs …

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Cloning And Characterization Of Subunits Of The T-Cell Receptor And Murine Leukemia Virus Enhancer Core-Binding Factor., Shuwen Wang, Qing Wang, Barbara E. Crute, Irena N. Melnikova, Susanna R. Keller, Nancy A. Speck Jun 1993

Cloning And Characterization Of Subunits Of The T-Cell Receptor And Murine Leukemia Virus Enhancer Core-Binding Factor., Shuwen Wang, Qing Wang, Barbara E. Crute, Irena N. Melnikova, Susanna R. Keller, Nancy A. Speck

Dartmouth Scholarship

Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major determinant of the thymic disease specificity of Moloney virus genetically maps to the conserved viral core motif in the Moloney virus enhancer. Point mutations introduced into the core site significantly shifted the disease specificity of the Moloney virus from thymic leukemia to erythroid leukemia (N.A. Speck, B. Renjifo, E. Golemis, T.N. Fredrickson, J.W. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We previously reported the purification of core-binding factors (CBF) from calf thymus nuclei (S. Wang and N.A. Speck, Mol. Cell. Biol. 12:89-102, 1992). CBF binds …

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Common Elements In Interleukin 4 And Insulin Signaling Pathways In Factor-Dependent Hematopoietic Cells., Ling-Mei Wang, Achsah D. A D Keegan, Weiqun Li, Gustav E. Lienhard May 1993

Common Elements In Interleukin 4 And Insulin Signaling Pathways In Factor-Dependent Hematopoietic Cells., Ling-Mei Wang, Achsah D. A D Keegan, Weiqun Li, Gustav E. Lienhard

Dartmouth Scholarship

Interleukin 4 (IL-4), insulin, and insulin-like growth factor I (IGF-I) efficiently induced DNA synthesis in the IL-3-dependent murine myeloid cell lines FDC-P1 and FDC-P2. Although these factors could not individually sustain long-term growth of these lines, a combination of IL-4 with either insulin or IGF-I did support continuous growth. The principal tyrosine-phosphorylated substrate observed in FDC cells stimulated with IL-4, previously designated 4PS, was of the same size (170 kDa) as the major substrate phosphorylated in response to insulin or IGF-I. These substrates had phosphopeptides of the same size when analyzed by digestion with Staphylococcus aureus V8 protease, and each …

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Isolation Of Interleukin 2-Induced Immediate-Early Genes., Carol Beadling, Kirk W. Johnson, Kendall A. Smith Apr 1993

Isolation Of Interleukin 2-Induced Immediate-Early Genes., Carol Beadling, Kirk W. Johnson, Kendall A. Smith

Dartmouth Scholarship

Clonal expansion of antigen-reactive T lymphocytes is driven by the lymphokine interleukin 2 (IL-2). To further elucidate the mechanisms of IL-2 action, we have utilized a differential hybridization procedure to clone IL-2-induced immediate-early genes from an IL-2-stimulated human T-cell cDNA library. To increase the frequency of IL-2-induced transcripts represented in the library, the protein synthesis inhibitor cycloheximide was included during the 2-hr IL-2 stimulation to superinduce gene expression, and the uridine analogue 4-thiouridine was utilized to enable selective purification of newly synthesized transcripts. From the enriched library, we have isolated eight IL-2-induced genes, six of which represent previously unrecognized human …

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Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel Nov 1992

Indistinguishable Nuclear Factor Binding To Functional Core Sites Of The T-Cell Receptor Delta And Murine Leukemia Virus Enhancers., Juan M. Redondo, Jeffrey L. Pfohl, Cristina Hernandez-Munain, Shuwen Wang, Nancy A. Speck, Michael S. Krangel

Dartmouth Scholarship

We have previously shown that the delta E3 site is an essential element for transcriptional activation by the human T-cell receptor (TCR) delta enhancer and identified two factors, NF-delta E3A and NF-delta E3C, that bound to overlapping core (TGTGGTTT) and E-box motifs within delta E3. In this study, we show that protein binding to the core motif is necessary but not sufficient for transcriptional activation by the delta E3 element. In contrast, protein binding to the E-box motif does not contribute significantly to enhancer activity. A similar core motif present within the enhancers of T-cell-tropic murine retroviruses has been shown …

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Purification Of Core-Binding Factor, A Protein That Binds The Conserved Core Site In Murine Leukemia Virus Enhancers., Shuwen W. Wang, Nancy A. Speck Jan 1992

Purification Of Core-Binding Factor, A Protein That Binds The Conserved Core Site In Murine Leukemia Virus Enhancers., Shuwen W. Wang, Nancy A. Speck

Dartmouth Scholarship

The Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major genetic determinant of the thymic disease specificity of the Moloney virus genetically maps to two protein binding sites in the Moloney virus enhancer, the leukemia virus factor b site and the adjacent core site. Point mutations introduced into either of these sites significantly shifts the disease specificity of the Moloney virus from thymic leukemia to erythroleukemia (N. A. Speck, B. Renjifo, E. Golemis, T. Frederickson, J. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We have purified several polypeptides that bind to the core site …

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Translocation Of The Glucose Transporter Glut4 In Cardiac Myocytes Of The Rat., Jan W. Slot, Hans J. Geuze, Sander Gigengack, David E. James, Gustav E. Lienhard Sep 1991

Translocation Of The Glucose Transporter Glut4 In Cardiac Myocytes Of The Rat., Jan W. Slot, Hans J. Geuze, Sander Gigengack, David E. James, Gustav E. Lienhard

Dartmouth Scholarship

The insulin-regulated glucose transporter GLUT4 was immunolocalized in rat cardiac muscle under conditions of basal and stimulated glucose uptake, achieved by fasting and a combined exercise/insulin stimulus, respectively. In basal myocytes there was very little (less than 1%) GLUT4 in the different domains of the plasma membrane (sarcolemma, intercalated disk, and transverse tubular system). GLUT4 was localized in small tubulo-vesicular elements that occur predominantly near the sarcolemma and the transverse tubular system and in the trans-Golgi region. Upon stimulation approximately 42% of GLUT4 was found in the plasma membrane. Each domain of the plasma membrane contributed equally to this effect. …

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Interleukin-2-Triggered Raf-1 Expression, Phosphorylation, And Associated Kinase Activity Increase Through G1 And S In Cd3-Stimulated Primary Human T Cells., Antanina Zmuidzinas, Harvey J. Mamon, Thomas M. Roberts, Kendall A. Smith May 1991

Interleukin-2-Triggered Raf-1 Expression, Phosphorylation, And Associated Kinase Activity Increase Through G1 And S In Cd3-Stimulated Primary Human T Cells., Antanina Zmuidzinas, Harvey J. Mamon, Thomas M. Roberts, Kendall A. Smith

Dartmouth Scholarship

To gain further insight into the role of Raf-1 in normal cell growth, c-raf-1 mRNA expression, Raf-1 protein production, and Raf-1-associated kinase activity in normal human T cells were analyzed. In contrast to the constitutive expression of Raf-1 in continuously proliferating cell lines, c-raf-1 mRNA and Raf-1 protein levels were barely detectable in freshly isolated G0 T lymphocytes. Previous work with fibroblasts has suggested that Raf-1 plays a signaling role in the G0-G1 phase transition. In T cells, triggering via the T-cell antigen receptor (TCR)-CD3 complex (TCR/CD3) resulted in an approximately fourfold increase in c-raf-1 mRNA. In addition, the promotion …

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Neurospora Crassa Clock-Controlled Genes Are Regulated At The Level Of Transcription., Jennifer J. Loros, Jay C. Dunlap Jan 1991

Neurospora Crassa Clock-Controlled Genes Are Regulated At The Level Of Transcription., Jennifer J. Loros, Jay C. Dunlap

Dartmouth Scholarship

Although an extensive number of biological processes are under the daily control of the circadian biological clock, little is known about how the clock maintains its regulatory networks within a cell. An important aspect of this temporal control is the daily control of gene expression. Previously we identified two morning-specific genes that are regulated by the clock through daily control of gene expression (J. Loros, S. Denome, and J.C. Dunlap, Science 243:385-388, 1989). We have now introduced a method for transcriptional analysis in Neurospora crassa and used this nuclear run-on procedure to show that regulation of mRNA abundance for these …

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K+ Efflux In Nih Mouse 3t3 Cells And Transformed Derivatives: Dependence On Extracellular Ca2+ And Phorbol Esters., Martin Lubin Jul 1988

K+ Efflux In Nih Mouse 3t3 Cells And Transformed Derivatives: Dependence On Extracellular Ca2+ And Phorbol Esters., Martin Lubin

Dartmouth Scholarship

In culture medium deficient in Ca2+, NIH mouse 3T3 cells lose K+, gain Na+, and stop growing. A marked increase in the rate of K+ efflux accounts for this loss; Na+, K+-ATPase pump activity increases but does not fully compensate for enhanced K+ efflux. Phorbol esters and cycloheximide inhibit K+ loss in Ca2+-deficient medium. Phorbol esters inhibit K+ efflux from human fibroblasts as well, even at physiological levels of Ca2+. Two cell lines derived from NIH-3T3, one transformed by a simian virus 40 deletion mutant, the other by the polyoma virus oncogene encoding the middle-sized tumor antigen, retain K+ and …

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Identification Of A Complex Associated With Processing And Polyadenylation In Vitro Of Herpes Simplex Virus Type 1 Thymidine Kinase Precursor Rna., Fang Zhang, Charles N. Cole Sep 1987

Identification Of A Complex Associated With Processing And Polyadenylation In Vitro Of Herpes Simplex Virus Type 1 Thymidine Kinase Precursor Rna., Fang Zhang, Charles N. Cole

Dartmouth Scholarship

Cleavage and polyadenylation of substrate RNAs containing the herpes simplex virus type 1 (HSV-1) thymidine kinase (tk) gene polyadenylation signal region were examined in HeLa cell nuclear extract. 3'-End RNA processing was accurate and efficient and required ATP and Mg2+. Cleavage, but not polyadenylation, occurred in the presence of EDTA or when ATP was replaced with 3' dATP (cordycepin) or AMP(CH2)PP, a nonhydrolyzable analog of ATP. Processing in vitro and in vivo showed the same signal element requirements: a series of substrates containing linker scanning, internal deletion, and small insertion mutations was processed with the same relative efficiencies and at …

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Fine-Structure Analysis Of The Processing And Polyadenylation Region Of The Herpes Simplex Virus Type 1 Thymidine Kinase Gene By Using Linker Scanning, Internal Deletion, And Insertion Mutations., Fang Zhang, Roger M. Denome, Charles N. Cole Dec 1986

Fine-Structure Analysis Of The Processing And Polyadenylation Region Of The Herpes Simplex Virus Type 1 Thymidine Kinase Gene By Using Linker Scanning, Internal Deletion, And Insertion Mutations., Fang Zhang, Roger M. Denome, Charles N. Cole

Dartmouth Scholarship

Most eucaryotic mRNAs are polyadenylated. In higher eucaryotes, the sequence AATAAA is located 7 to 30 base pairs (bp) upstream from the site of processing and polyadenylation and is a critical part of the signal for processing and polyadenylation. Efficient cleavage and polyadenylation also require sequences downstream of polyadenylation sites. The herpes simplex virus type 1 thymidine kinase (tk) gene contains two copies of the AATAAA hexanucleotide and a GT box (18 of 19 consecutive residues are G or T) previously shown to be required for efficient processing and polyadenylation of tk mRNA (C. N. Cole and T. P. Stacy, …

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Absence Of A Structural Basis For Intracellular Recognition And Differential Localization Of Nuclear And Plasma Membrane-Associated Forms Of Simian Virus 40 Large Tumor Antigen., Donald L. Jarvis, Charles N. Cole, Janet S. Butel Mar 1986

Absence Of A Structural Basis For Intracellular Recognition And Differential Localization Of Nuclear And Plasma Membrane-Associated Forms Of Simian Virus 40 Large Tumor Antigen., Donald L. Jarvis, Charles N. Cole, Janet S. Butel

Dartmouth Scholarship

The simian virus 40 large tumor antigen (T-ag) is found in both the nuclei (nT-ag) and plasma membranes (mT-ag) of simian virus 40-infected or -transformed cells. It is not known how newly synthesized T-ag molecules are recognized, sorted, and transported to their ultimate subcellular destinations. One possibility is that these events depend upon structural differences between nT-ag and mT-ag. To test this possibility, we compared the structures of nT-ag and mT-ag from simian virus 40-infected cells. No differences between the two forms of T-ag were detected by migration in polyacrylamide gels, by Staphylococcus aureus V8 partial proteolytic mapping of methionine- …

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Identification Of Sequences In The Herpes Simplex Virus Thymidine Kinase Gene Required For Efficient Processing And Polyadenylation., Charles N. Cole, Terryl P. Stacy Aug 1985

Identification Of Sequences In The Herpes Simplex Virus Thymidine Kinase Gene Required For Efficient Processing And Polyadenylation., Charles N. Cole, Terryl P. Stacy

Dartmouth Scholarship

The herpes simplex virus (HSV) type 1 thymidine kinase gene (tk) was resected from its 3' end with BAL 31 exonuclease. Two sets of plasmids were isolated that lacked information distal to the two copies of the hexanucleotide 5'-AATAAA-3' located at the 3' end of the HSV tk gene. The presence of a simian virus 40 origin of DNA replication in each plasmid facilitated analysis of patterns of transcription in transfected Cos-1 monkey cells. Transcription analyses were performed with an S1 nuclease protection assay. Efficient processing and polyadenylation at the normal site still occurred when all sequences more than 44 …

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Rat Dendritic Cells Function As Accessory Cells And Control The Production Of A Soluble Factor Required For Mitogenic Responses Of T Lymphocytes., Wolfgang E. Klinkert, Jon H. Labadie, James P. O'Brien, Carl F. Beyer, William E. Bowers Sep 1980

Rat Dendritic Cells Function As Accessory Cells And Control The Production Of A Soluble Factor Required For Mitogenic Responses Of T Lymphocytes., Wolfgang E. Klinkert, Jon H. Labadie, James P. O'Brien, Carl F. Beyer, William E. Bowers

Dartmouth Scholarship

Transformation of T lymphocytes, induced by treatment with periodate or with neuraminidase plus galactose oxidase, requires the participation of accessory cells. Procedures were developed for the fractionation of rat lymph node cells, by which most of the lymphocytes can be recovered as a major population of cells that do not respond to mitogenic stimulation unless accessory cells from a separated minor population are added. Further purification led to a 1000-fold overall increase in accessory activity per cell, with a 50-70% yield. The purest preparations were virtually free of macrophages and contained more than 90% typical dendritic cells. Maximum responses occurred …

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