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Articles 181 - 209 of 209
Full-Text Articles in Life Sciences
A Novel High-Cell-Density Protein Expression System Based On Ralstonia Eutropha, Sriram Srinivasan, Gavin C. Barnard, Tillman U. Gerngross
A Novel High-Cell-Density Protein Expression System Based On Ralstonia Eutropha, Sriram Srinivasan, Gavin C. Barnard, Tillman U. Gerngross
Dartmouth Scholarship
We describe the development of a novel protein expression system based on the industrial fermentation organism Ralstonia eutropha (formerly known as Alcaligenes eutrophus) NCIMB 40124. This new system over- comes some of the shortcomings of traditional Escherichia coli-based protein expression systems, particularly the propensity of such systems to form inclusion bodies during high-level expression. Using a proteomics approach, we identified promoters that can be induced by simple process parameters or medium compositions in high-density cell culture or shake flasks, respectively. By combining newly developed molecular biological tools with a high-cell-density fermentation process, we were able to produce high levels ( …
Regulation Of Flagellar Dynein By Calcium And A Role For An Axonemal Calmodulin And Calmodulin-Dependent Kinase, Elizabeth F. Smith
Regulation Of Flagellar Dynein By Calcium And A Role For An Axonemal Calmodulin And Calmodulin-Dependent Kinase, Elizabeth F. Smith
Dartmouth Scholarship
Ciliary and flagellar motility is regulated by changes in intraflagellar calcium. However, the molecular mechanism by which calcium controls motility is unknown. We tested the hypothesis that calcium regulates motility by controlling dynein-driven microtubule sliding and that the central pair and radial spokes are involved in this regulation. We isolated axonemes from Chlamydomonasmutants and measured microtubule sliding velocity in buffers containing 1 mM ATP and various concentrations of calcium. In buffers with pCa > 8, microtubule sliding velocity in axonemes lacking the central apparatus (pf18 and pf15) was reduced compared with that of wild-type axonemes. In contrast, at …
Type 4 Pilus Biogenesis And Type Ii-Mediated Protein Secretion By Vibrio Cholerae Occur Independently Of The Tonb-Facilitated Proton Motive Force, Niranjan Bose, Shelley M. Payne, Ronald K. Taylor
Type 4 Pilus Biogenesis And Type Ii-Mediated Protein Secretion By Vibrio Cholerae Occur Independently Of The Tonb-Facilitated Proton Motive Force, Niranjan Bose, Shelley M. Payne, Ronald K. Taylor
Dartmouth Scholarship
In Vibrio cholerae, elaboration of toxin-coregulated pilus and protein secretion by the extracellular protein secretion apparatus occurred in the absence of both TonB systems. In contrast, the cognate putative ATPases were required for each process and could not substitute for each other.
Ube1l Is A Retinoid Target That Triggers Pml/Rarα Degradation And Apoptosis In Acute Promyelocytic Leukemia, Sutisak Kitareewan, Ian Pitha-Rowe, David Sekula, Christopher H. Lowrey, Michael J. Nemeth, Todd R. Golub, Sarah J. Freemantle, Ethan Dmitrovsky
Ube1l Is A Retinoid Target That Triggers Pml/Rarα Degradation And Apoptosis In Acute Promyelocytic Leukemia, Sutisak Kitareewan, Ian Pitha-Rowe, David Sekula, Christopher H. Lowrey, Michael J. Nemeth, Todd R. Golub, Sarah J. Freemantle, Ethan Dmitrovsky
Dartmouth Scholarship
All-trans-retinoic acid (RA) treatment induces remissions in acute promyelocytic leukemia (APL) cases expressing the t(15;17) product, promyelocytic leukemia (PML)/RA receptor α (RARα). Microarray analyses previously revealed induction of UBE1L (ubiquitin-activating enzyme E1-like) after RA treatment of NB4 APL cells. We report here that this occurs within 3 h in RA-sensitive but not RA-resistant APL cells, implicating UBE1L as a direct retinoid target. A 1.3-kb fragment of the UBE1L promoter was capable of mediating transcriptional response to RA in a retinoid receptor-selective manner. PML/RARα, a repressor of RA target genes, abolished this UBE1L promoter activity. A hallmark of …
Erv14p Directs A Transmembrane Secretory Protein Into Copii-Coated Transport Vesicles, Jacqueline Powers, Charles Barlowe
Erv14p Directs A Transmembrane Secretory Protein Into Copii-Coated Transport Vesicles, Jacqueline Powers, Charles Barlowe
Dartmouth Scholarship
Erv14p is a conserved integral membrane protein that traffics in COPII-coated vesicles and localizes to the early secretory pathway in yeast. Deletion of ERV14 causes a defect in polarized growth because Axl2p, a transmembrane secretory protein, accumulates in the endoplasmic reticulum and is not delivered to its site of function on the cell surface. Herein, we show that Erv14p is required for selection of Axl2p into COPII vesicles and for efficient formation of these vesicles. Erv14p binds to subunits of the COPII coat and binding depends on conserved residues in a cytoplasmically exposed loop domain of Erv14p. When mutations are …
Genomic Analysis Of Homotypic Vacuole Fusion, E Scott Seeley, Masashi Kato, Nathan Margolis, William Wickner, Gary Eitzen
Genomic Analysis Of Homotypic Vacuole Fusion, E Scott Seeley, Masashi Kato, Nathan Margolis, William Wickner, Gary Eitzen
Dartmouth Scholarship
Yeast vacuoles undergo fission and homotypic fusion, yielding one to three vacuoles per cell at steady state. Defects in vacuole fusion result in vacuole fragmentation. We have screened 4828 yeast strains, each with a deletion of a nonessential gene, for vacuole morphology defects. Fragmented vacuoles were found in strains deleted for genes encoding known fusion catalysts as well as 19 enzymes of lipid metabolism, 4 SNAREs, 12 GTPases and GTPase effectors, 9 additional known vacuole protein-sorting genes, 16 protein kinases, 2 phosphatases, 11 cytoskeletal proteins, and 28 genes of unknown function. Vacuole fusion and vacuole protein sorting are catalyzed by …
Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum
Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum
Dartmouth Scholarship
Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener, eutrophic lakes often carry less mercury. In this study, we experimentally tested the hypothesis that increasing algal biomass reduces mercury accumulation at higher trophic levels through the dilution of mercury in consumed algal cells. Under bloom dilution, as algal biomass …
Marek's Disease Virus (Mdv) Encodes An Interleukin-8 Homolog (Vil-8): Characterization Of The Vil-8 Protein And A Vil-8 Deletion Mutant Mdv, Mark S. Parcells, Su-Fang Lin, Robert L. Dienglewicz, Vladimir Majerciak, Dan R. Robinson, Hua-Chien Chen, Zining Wu, George R. Dubyak, Peter Brunovskis, Henry D. Hunt
Marek's Disease Virus (Mdv) Encodes An Interleukin-8 Homolog (Vil-8): Characterization Of The Vil-8 Protein And A Vil-8 Deletion Mutant Mdv, Mark S. Parcells, Su-Fang Lin, Robert L. Dienglewicz, Vladimir Majerciak, Dan R. Robinson, Hua-Chien Chen, Zining Wu, George R. Dubyak, Peter Brunovskis, Henry D. Hunt
Dartmouth Scholarship
Chemokines induce chemotaxis, cell migration, and inflammatory responses. We report the identification of an interleukin-8 (IL-8) homolog, termed vIL-8, encoded within the genome of Marek's disease virus (MDV). The 134-amino-acid vIL-8 shares closest homology to mammalian and avian IL-8, molecules representing the prototype CXC chemokine. The gene for vIL-8 consists of three exons which map to the BamHI-L fragment within the repeats flanking the unique long region of the MDV genome. A 0.7-kb transcript encoding vIL-8 was detected in an n-butyrate-treated, MDV-transformed T-lymphoblastoid cell line, MSB-1. This induction is essentially abolished by cycloheximide and herpesvirus DNA polymerase inhibitor phosphonoacetate, indicating …
The Mannose-Sensitive Hemagglutinin Of Vibrio Cholerae Promotes Adherence To Zooplankton, Deborah A. Chiavelli, Jane W. Marsh, Ronald K. Taylor
The Mannose-Sensitive Hemagglutinin Of Vibrio Cholerae Promotes Adherence To Zooplankton, Deborah A. Chiavelli, Jane W. Marsh, Ronald K. Taylor
Dartmouth Scholarship
The bacterium Vibrio cholerae, the etiological agent of cholera, is often found attached to plankton, a property that is thought to contribute to its environmental persistence in aquatic habitats. The V. cholerae O1 El Tor biotype and V. cholerae O139 strains produce a surface pilus termed the mannose-sensitive hemagglutinin (MSHA), whereas V. cholerae O1 classical biotype strains do not. Although V. cholerae O1 classical does not elaborate MSHA, the gene is present and expressed at a level comparable to that of the other strains. Since V. cholerae O1 El Tor and V. cholerae O139 have displaced V. cholerae O1 classical …
Nuclear Export Of 60s Ribosomal Subunits Depends On Xpo1p And Requires A Nuclear Export Sequence-Containing Factor, Nmd3p, That Associates With The Large Subunit Protein Rpl10p, Olivier Gadal, Daniela Strau, Jacques Kessl, Bernard Trumpower
Nuclear Export Of 60s Ribosomal Subunits Depends On Xpo1p And Requires A Nuclear Export Sequence-Containing Factor, Nmd3p, That Associates With The Large Subunit Protein Rpl10p, Olivier Gadal, Daniela Strau, Jacques Kessl, Bernard Trumpower
Dartmouth Scholarship
Nuclear export of ribosomes requires a subset of nucleoporins and the Ran system, but specific transport factors have not been identified. Using a large subunit reporter (Rpl25p-eGFP), we have isolated several temperature-sensitive ribosomal export (rix) mutants. One of these corresponds to the ribosomal protein Rpl10p, which interacts directly with Nmd3p, a conserved and essential protein associated with 60S subunits. We find that thermosensitive nmd3 mutants are impaired in large subunit export. Strikingly, Nmd3p shuttles between the nucleus and cytoplasm and is exported by the nuclear export receptor Xpo1p. Moreover, we show that export of 60S subunits is Xpo1p dependent. We …
Both An N-Terminal 65-Kda Domain And A C-Terminal 30-Kda Domain Of Seca Cycle Into The Membrane At Secyeg During Translocation, Jerry Eichler, William Wickner
Both An N-Terminal 65-Kda Domain And A C-Terminal 30-Kda Domain Of Seca Cycle Into The Membrane At Secyeg During Translocation, Jerry Eichler, William Wickner
Dartmouth Scholarship
SecA, a 102-kDa hydrophilic protein, couples the energy of ATP binding to the translocation of preprotein across the bacterial inner membrane. SecA function and topology were studied with metabolically labeled [35S]SecA and with inner membrane vesicles from cells that overex- pressed SecYEGDFyajC, the integral domain of preprotein translocase. During translocation in the presence of ATP and preprotein, a 65-kDa N-terminal domain of SecA is protected from proteolytic digestion through insertion into the mem- brane, as previously reported for a 30-kDa C-terminal domain [Economou, A. & Wickner, W. (1994) Cell 78, 835–843]. Insertion of both domains occurs at saturable SecYEGDFyajC sites …
The Product Of The Saccharomyces Cerevisiae Rss1 Gene, Identified As A High-Copy Suppressor Of The Rat7-1 Temperature-Sensitive Allele Of The Rat7/Nup159 Nucleoporin, Is Required For Efficient Mrna Export, Veronica Del Priore, Christine A. Snay, Andre Bahr, Charles N. Cole
The Product Of The Saccharomyces Cerevisiae Rss1 Gene, Identified As A High-Copy Suppressor Of The Rat7-1 Temperature-Sensitive Allele Of The Rat7/Nup159 Nucleoporin, Is Required For Efficient Mrna Export, Veronica Del Priore, Christine A. Snay, Andre Bahr, Charles N. Cole
Dartmouth Scholarship
RAT7/NUP159 was identified previously in a screen for genes whose products are important for nucleocytoplasmic export of poly(A)+ RNA and encodes an essential nucleoporin. We report here the identification of RSS1 (Rat Seven Suppressor) as a high-copy extragenic suppressor of the rat7-1 temperature-sensitive allele. Rss1p encodes a novel essential protein of 538 amino acids, which contains an extended predicted coiled-coil domain and is located both at nuclear pore complexes (NPCs) and in the cytoplasm. RSS1 is the first reported high-copy extragenic suppressor of a mutant nucleoporin. Overexpression of Rss1p partially suppresses the defects in nucleocytoplasmic export of poly(A)+ RNA, rRNA …
A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot
A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot
Dartmouth Scholarship
Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, …
Mutation Or Deletion Of The Saccharomyces Cerevisiae Rat3/Nup133 Gene Causes Temperature-Dependent Nuclear Accumulation Of Poly(A)+ Rna And Constitutive Clustering Of Nuclear Pore Complexes, Ou Li, Catherine V. Heath, David C. Amberg, Thomas C. Dockendorff, Connie S. Copeland, Michael Snyder, Charles N. Cole
Mutation Or Deletion Of The Saccharomyces Cerevisiae Rat3/Nup133 Gene Causes Temperature-Dependent Nuclear Accumulation Of Poly(A)+ Rna And Constitutive Clustering Of Nuclear Pore Complexes, Ou Li, Catherine V. Heath, David C. Amberg, Thomas C. Dockendorff, Connie S. Copeland, Michael Snyder, Charles N. Cole
Dartmouth Scholarship
To identify genes whose products play potential roles in the nucleocytoplasmic export of messenger RNA, we isolated temperature-sensitive strains of Saccharomyces cerevisiae and examined them by fluorescent in situ hybridization. With the use of a digoxigen-tagged oligo-(dT)50 probe, we identified those that showed nuclear accumulation of poly(A)+ RNA when cells were shifted to the nonpermissive temperature. We describe here the properties of yeast strains bearing the rat3-1 mutation (RAT-ribonucleic acid trafficking) and the cloning of the RAT3 gene. When cultured at the permissive temperature of 23 degrees C, fewer than 10% of cells carrying the rat3-1 allele showed nuclear accumulation …
Protein-Peptide Interactions Analyzed With The Yeast Two-Hybrid System, Meijia Yang, Zining Wu, Stanley Fields
Protein-Peptide Interactions Analyzed With The Yeast Two-Hybrid System, Meijia Yang, Zining Wu, Stanley Fields
Dartmouth Scholarship
The yeast two-hybrid system was used to screen a library of random peptides fused to a transcriptional activation domain in order to identify peptides capable of binding to the retinoblastoma protein (Rb). Seven peptides were identified, allof which contain the Leu-X-Cys-X-Glu motif found in Rb-binding proteins, although their activity in the yeast assay variedover a 40-fold range. Mutagenesis of the DNA encoding two of these peptides followed by screening in the two-hybrid systemallowed the delineation of residues apart from the invariant Leu, Cys and Glu that affect binding to Rb. Binding affinities of a peptide and one of its variants …
A Thyroid Hormone-Regulated Gene In Xenopus Laevis Encodes A Type Iii Iodothyronine 5-Deiodinase., Donald L. St Germain, Robert Schwartzman, Walburga Croteau, Akira Kanamori, Zhou Wang, Donald D. Brown, Valerie Galton
A Thyroid Hormone-Regulated Gene In Xenopus Laevis Encodes A Type Iii Iodothyronine 5-Deiodinase., Donald L. St Germain, Robert Schwartzman, Walburga Croteau, Akira Kanamori, Zhou Wang, Donald D. Brown, Valerie Galton
Dartmouth Scholarship
The type III iodothyronine 5-deiodinase metabolizes thyroxine and 3,5,3'-triiodothyronine to inactive metabolites by catalyzing the removal of iodine from the inner ring. The enzyme is expressed in a tissue-specific pattern during particular stages of development in amphibia, birds, and mammals. Recently, a PCR-based subtractive hybridization technique has been used to isolate cDNAs prepared from Xenopus laevis tadpole tail mRNA that represent genes upregulated by thyroid hormone during metamorphosis. Sequence analysis of one of these cDNAs (XL-15) revealed regions of homology to the mRNA encoding the rat type I (outer ring) 5'-deiodinase, including a conserved UGA codon that encodes selenocysteine in …
Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel
Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel
Dartmouth Scholarship
Chromatin in eukaryotic nuclei is thought to be partitioned into functional loop domains that are generated by the binding of defined DNA sequences, named MARs (matrix attachment regions), to the nuclear matrix. We have previously identified B-type lamins as MAR-binding matrix components (M. E. E. Ludérus, A. de Graaf, E. Mattia, J. L. den Blaauwen, M. A. Grande, L. de Jong, and R. van Driel, Cell 70:949-959, 1992). Here we show that A-type lamins and the structurally related proteins desmin and NuMA also specifically bind MARs in vitro. We studied the interaction between MARs and lamin polymers in molecular detail …
Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff
Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff
Dartmouth Scholarship
The mechanisms involved in retinoic acid (RA)-mediated regulation of the collagenase gene in a rabbit synovial fibroblast cell line (HIG82) were investigated. When HIG82 cells are cotransfected with expression vectors containing cDNAs for retinoic acid receptor (RAR) α1, β2, or γ1 and collagenase promoter-driven CAT reporter constructs, only RAR-γ1 represses basal CAT expression upon RA treatment, while RAR-α1, β2, and γ1 all suppress phorbol-induced CAT expression. Thus, transcriptional regulation of collagenase by RA is mediated by RARs in an RAR-type specific manner. Using mutatlonal and deletional analysis, we find that interaction between elements within 182 bp collagenase promoter plays an …
Transformation Of A Continuous Rat Embryo Fibroblast Cell Line Requires Three Separate Domains Of Simian Virus 40 Large T Antigen., Jiyue Zhu, Philip W. Rice, Lisa Gorsch, Marina Abate, Charles N. Cole
Transformation Of A Continuous Rat Embryo Fibroblast Cell Line Requires Three Separate Domains Of Simian Virus 40 Large T Antigen., Jiyue Zhu, Philip W. Rice, Lisa Gorsch, Marina Abate, Charles N. Cole
Dartmouth Scholarship
Mouse C3H 10T1/2 cells and the established rat embryo fibroblast cell line REF-52 are two cell lines widely used in studies of viral transformation. Studies have shown that transformation of 10T1/2 cells requires only the amino-terminal 121 amino acids of simian virus 40 (SV40) large T antigen, while transformation of REF-52 cells requires considerably more of large T antigen, extending from near the N terminus to beyond residue 600. The ability of a large set of linker insertion, small deletion, and point mutants of SV40 T antigen to transform these two cell lines and to bind p105Rb was determined. Transformation …
Citrate As A Siderophore In Bradyrhizobium Japonicum., Mary Lou Guerinot, Erik J. Meidl, Ora Plessner
Citrate As A Siderophore In Bradyrhizobium Japonicum., Mary Lou Guerinot, Erik J. Meidl, Ora Plessner
Dartmouth Scholarship
Under iron-limiting conditions, many bacteria secrete ferric iron-specific ligands, generically termed siderophores, to aid in the sequestering and transport of iron. One strain of the nitrogen-fixing soybean symbiont Bradyrhizobium japonicum, 61A152, was shown to produce a siderophore when 20 B. japonicum strains were screened with all six chemical assays commonly used to detect such production. Production by strain 61A152 was detected via the chrome azurol S assay, a general test for siderophores which is independent of siderophore structure. The iron-chelating compound was neither a catechol nor a hydroxamate and was ninhydrin negative. It was determined to be citric acid via …
In Vitro Reconstitution Of Exocytosis From Sea Urchin Egg Plasma Membrane And Isolated Cortical Vesicles, Joseph H. Crabb, Paul A. Modern, Robert C. Jackson
In Vitro Reconstitution Of Exocytosis From Sea Urchin Egg Plasma Membrane And Isolated Cortical Vesicles, Joseph H. Crabb, Paul A. Modern, Robert C. Jackson
Dartmouth Scholarship
We have succeeded in reconstituting an exocytotically active egg cortex fraction by recombining purified cortical vesicles (CVs) with egg plasma membrane (PM). CVs were dislodged from a suspension of egg cortex by gentle homogenization in a dissociative buffer with a pH of 9.1, and purified by two rounds of differential centrifugation. Egg PM was prepared by shearing the cortical vesicles from a cortical lawn preparation with a jet of isotonic buffer. PM lawns produced by this procedure consist of an array of CV-free PM fragments attached via their extracellular surface to a polylysine coated glass slide. When a neutralized suspension …
Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue
Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue
Dartmouth Scholarship
Microtubule proteins isolated from calf brain will undergo gelation-contraction in the presence of ATP. We have now examined this process by video-enhanced contrast microscopy. After ATP addition to steady-state microtubules, slow (1-5 micron/min), linear movements of particles and microtubules toward aggregation centers occur. The resulting structures resemble mitotic spindle asters. During the time when gel contraction occurs, asters move (at 1-5 micron/min) toward other nearby asters. This is accompanied by the apparent shortening of the microtubules running between the asters. This is the first example of isolated microtubules undergoing a process that has similarities to half-spindle shortening during anaphase A. …
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
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- …
Two Separable Functional Domains Of Simian Virus 40 Large T Antigen: Carboxyl-Terminal Region Of Simian Virus 40 Large T Antigen Is Required For Efficient Capsid Protein Synthesis., Joanne Tornow, Maryellen Polvino-Bodnar, George Santangelo, Charles N. Cole
Two Separable Functional Domains Of Simian Virus 40 Large T Antigen: Carboxyl-Terminal Region Of Simian Virus 40 Large T Antigen Is Required For Efficient Capsid Protein Synthesis., Joanne Tornow, Maryellen Polvino-Bodnar, George Santangelo, Charles N. Cole
Dartmouth Scholarship
The carboxyl-terminal portion of simian virus 40 large T antigen is essential for productive infection of CV-1 and CV-1p green monkey kidney cells. Mutant dlA2459, lacking 14 base pairs at 0.193 map units, was positive for viral DNA replication, but unable to form plaques in CV-1p cells (J. Tornow and C.N. Cole, J. Virol. 47:487-494, 1983). In this report, the defect of dlA2459 is further defined. Simian virus 40 late mRNAs were transcribed, polyadenylated, spliced, and transported in dlA2459-infected cells, but the level of capsid proteins produced in infected CV-1 green monkey kidney cells was extremely low. dlA2459 large T …
Isolation Of A Collagenase Cdna Clone And Measurement Of Changing Collagenase Mrna Levels During Induction In Rabbit Synovial Fibroblasts., Robert H. Gross, Lynn A. Sheldon, Colin F. Fletcher, Constance E. Brinckerhoff
Isolation Of A Collagenase Cdna Clone And Measurement Of Changing Collagenase Mrna Levels During Induction In Rabbit Synovial Fibroblasts., Robert H. Gross, Lynn A. Sheldon, Colin F. Fletcher, Constance E. Brinckerhoff
Dartmouth Scholarship
To facilitate our studies on the mechanisms controlling collagenase production at a molecular level in rabbit synovial fibroblasts, we have constructed a cDNA library using mRNAs isolated from cells induced with crystals of monosodium urate monohydrate. We have screened this library with cDNA probes made from induced and control mRNA populations. From among 30 clones that hybridized preferentially to the induced-cell probe, 4 contained collagenase sequences. The largest, a clone of 650 base pairs, was identified by its ability to hybrid select a mRNA that could be translated in a cell-free system into a product that was precipitable with monospecific …
Recombinant Immune Interferon Increases Immunoglobulin G Fc Receptors On Cultured Human Mononuclear Phagocytes, Paul M. Guyre, Peter M. Morganelli, Renee Miller
Recombinant Immune Interferon Increases Immunoglobulin G Fc Receptors On Cultured Human Mononuclear Phagocytes, Paul M. Guyre, Peter M. Morganelli, Renee Miller
Dartmouth Scholarship
Although recent studies suggest that interferons can increase the number of IgG Fc receptor (FcR gamma) sites on mouse macrophages, direct assessment of similar effects on human mononuclear phagocytes is lacking. We therefore measured the specific binding of 125I- and fluorescein-labeled IgG1 to human monocytes and leukemic cell lines after culture in vitro with highly purified human interferons. We report that natural and recombinant human gamma-interferon causes a dramatic (nearly 10-fold) increase in the number of FcR gamma on normal human monocytes and on the human cell lines HL-60 and U-937. Alpha and beta-interferons cause a modest but significant increase …
Spermidine-Condensed Phi X174 Dna Cleavage By Micrococcal Nuclease: Torus Cleavage Model And Evidence For Unidirectional Circumferential Dna Wrapping., Kenneth A. Marx, Thomas C. Reynolds
Spermidine-Condensed Phi X174 Dna Cleavage By Micrococcal Nuclease: Torus Cleavage Model And Evidence For Unidirectional Circumferential Dna Wrapping., Kenneth A. Marx, Thomas C. Reynolds
Dartmouth Scholarship
Spermidine-condensed phi X174 replicative form (RF) II DNA was digested with micrococcal nuclease to yield seven identifiable DNA bands forming an arithmetic fragment-length series. The DNA monomer unit length was found to be 780 +/- 80 base pairs. This result is most consistent with a proposed model for micrococcal nuclease cleavage of a DNA torus organized by the unidirectional, circumferential wrapping of B-geometry DNA. By a topological consideration, the blunt-end-rod-fusion model for torus formation [Eickbush, T. H. & Moudrianakis, E. N. (1978) Cell 13, 295-306] is shown to be inconsistent with our empirical solution results. We propose a continuous, circumferential …
Synthesis Of Low Molecular Weight Heat Shock Peptides Stimulated By Ecdysterone In A Cultured Drosophila Cell Line., Robert C. Ireland, Edward M. Berger
Synthesis Of Low Molecular Weight Heat Shock Peptides Stimulated By Ecdysterone In A Cultured Drosophila Cell Line., Robert C. Ireland, Edward M. Berger
Dartmouth Scholarship
Treatment of Schneider's line 3 Drosophila cells with the steroid hormone ecdysterone rapidly stimulated the synthesis and accumulation of the polypeptide previously designated p7 [Berger, E. M., Ireland, R. C. & Wyss, C. (1980) Somatic Cell Genet. 6, 119-129]. In this report, p7 is identified as the 23,000-dalton heat shock polypeptide (hsp23). In addition to hsp23, the synthesis of the low molecular weight heat shock polypeptides hsp22, hsp26, and hsp27 was also stimulated by ecdysterone, although to different extents. Hybridization of a nick-translated genomic clone containing the hsp23 gene to a total RNA blot showed that ecdysterone stimulation of hsp23 …
Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie
Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie
Dartmouth Scholarship
A physiologically characterized radiolabeled neurotoxin complex obtained from venom of the scorpion Leiurus quinquestriatus has been used to identify detergent-solubilized presumptive sodium channel components in sucrose gradients. This toxin-binding component is found in extracts prepared from three sources of excitable membrane but appears to be absent from similar extracts prepared from nonexcitable membrane or from Torpedo californica membrane. Procedures that destroy the physiological activity of the Leiurus neurotoxin lead to a corresponding loss of toxin binding to the putative sodium channel component. The major component recognized by the Leiurus toxin sediments at 6.5 S. Scatchard analysis of quantitative binding experiments …