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1995

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Articles 1 - 30 of 36

Full-Text Articles in Cell Biology

Connexin32 Is A Myelin-Related Protein In The Pns And Cns, Steven S. Scherer, Suzanne M. Deschênes, Yi-Tian Xu, Judith B. Grinspan, Kenneth H. Fischbeck, David L. Paul Dec 1995

Connexin32 Is A Myelin-Related Protein In The Pns And Cns, Steven S. Scherer, Suzanne M. Deschênes, Yi-Tian Xu, Judith B. Grinspan, Kenneth H. Fischbeck, David L. Paul

Biology Faculty Publications

We have examined the expression of a gap junction protein, connexin32 (Cx32), in Schwann cells and oligodendrocytes. In peripheral nerve, Cx32 is found in the paranodal myelin loops and Schmidt-Lanterman incisures of myelinating Schwann cells, and the levels of Cx32 protein and mRNA change in parallel with those of other myelin-related genes during development, Wallerian degeneration, and axonal regeneration. In the central nervous system, Cx32 is found in oligodendrocytes and their processes, but not in compact myelin, and the levels of Cx32 protein and mRNA increase during development in parallel with those of the other myelin genes. Thus, Cx32 is ...


Nonrandom Gene Organization: Structural Arrangements Of Specific Pre-Mrna Transcription And Splicing With Sc-35 Domains, Yigong P. Xing, Carol V. Johnson, Phillip T. Moen, John A. Mcneil, Jeanne B. Lawrence Dec 1995

Nonrandom Gene Organization: Structural Arrangements Of Specific Pre-Mrna Transcription And Splicing With Sc-35 Domains, Yigong P. Xing, Carol V. Johnson, Phillip T. Moen, John A. Mcneil, Jeanne B. Lawrence

GSBS Student Publications

This work demonstrates a highly nonrandom distribution of specific genes relative to nuclear domains enriched in splicing factors and poly(A)+ RNA, and provides evidence for the direct involvement of these in pre-mRNA metabolism. As investigated in hundreds of diploid fibroblasts, human collagen I alpha 1 and beta-actin DNA/RNA showed a very high degree of spatial association with SC-35 domains, whereas three nontranscribed genes, myosin heavy chain, neurotensin, and albumin, showed no such preferential association. Collagen I alpha 1 RNA accumulates within the more central region of the domain, whereas beta-actin RNA localizes at the periphery. A novel approach ...


Ponticulin Plays A Role In The Positional Stabilization Of Pseudopods, D. C. Shutt, D. Wessels, K. Wagenknecht, A. Chandrasekhar, Anne L. Hitt, Elizabeth J. Luna, D. R. Soll Dec 1995

Ponticulin Plays A Role In The Positional Stabilization Of Pseudopods, D. C. Shutt, D. Wessels, K. Wagenknecht, A. Chandrasekhar, Anne L. Hitt, Elizabeth J. Luna, D. R. Soll

Women’s Health Research Faculty Publications

Ponticulin is a 17-kD glycoprotein that represents a major high affinity link between the plasma membrane and the cortical actin network of Dictyostelium. To assess the role of ponticulin in pseudopod extension and retraction, the motile behavior of two independently generated mutants lacking ponticulin was analyzed using computer-assisted two- and three-dimensional motion analysis systems. More than half of the lateral pseudopods formed off the substratum by ponticulin-minus cells slipped relative to the substratum during extension and retraction. In contrast, all pseudopods formed off the substratum by wild-type cells were positionally fixed in relation to the substratum. Ponticulin-minus cells also formed ...


Molecular Characterization Of Mitofilin, A Novel, Mitochondrial, Coiled Coil Protein, And The Relationship Between Organism Complexity And Coiled Coil Protein-Mediated Structure: A Dissertation, Paul R. Odgren Nov 1995

Molecular Characterization Of Mitofilin, A Novel, Mitochondrial, Coiled Coil Protein, And The Relationship Between Organism Complexity And Coiled Coil Protein-Mediated Structure: A Dissertation, Paul R. Odgren

GSBS Dissertations and Theses

In the course of experiments designed to identify and characterize structural proteins of the nuclear matrix, one antibody was generated which recognized an extraction-resistant cytoplasmic protein. This antibody was used as the starting point in the cloning and molecular characterization of a novel protein of the inter-membrane space of the mitochondrion which has been named mitofilin. Mitofilin is expressed in all human cell types, and murine homologues also exist. Mitofilin associates only with mitochondria and not with other membrane-bounded organelles such as Golgi or endoplasmic reticulum. This observation has been confirmed both by biochemical fractionation and multi-label fluorescence microscopy. Recombinant ...


Expression Of Cell Cycle Regulatory Factors In Differentiating Osteoblasts: Postproliferative Up-Regulation Of Cyclins B And E, Elisheva Smith, Baruch Frenkel, Robert Schlegel, Antonio Giordano, Jane B. Lian, Janet L. Stein, Gary S. Stein Nov 1995

Expression Of Cell Cycle Regulatory Factors In Differentiating Osteoblasts: Postproliferative Up-Regulation Of Cyclins B And E, Elisheva Smith, Baruch Frenkel, Robert Schlegel, Antonio Giordano, Jane B. Lian, Janet L. Stein, Gary S. Stein

Open Access Articles

The representation of cyclins and cyclin-dependent kinases (cdks) was analyzed during progressive development of the bone cell phenotype in cultures of normal diploid rat calvarial osteoblasts. Three developmental stages were examined: (a) proliferation; (b) monolayer confluency; and (c) mineralization of the bone extracellular matrix. We demonstrate that the presence of cyclins and cdks is not restricted to the proliferation period. Consistent with their role in cell cycle progression, cdc2 and cdk2 decrease postproliferatively. However, cdk4 and cyclins A, B, and D1 persist in confluent cells. Cyclin E is significantly up-regulated during the extracellular matrix mineralization developmental period. Examination of the ...


The Essential Ost2 Gene Encodes The 16-Kd Subunit Of The Yeast Oligosaccharyltransferase, A Highly Conserved Protein Expressed In Diverse Eukaryotic Organisms, Susana Silberstein, Pallia G. Collins, Daniel J. Kelleher, Reid Gilmore Oct 1995

The Essential Ost2 Gene Encodes The 16-Kd Subunit Of The Yeast Oligosaccharyltransferase, A Highly Conserved Protein Expressed In Diverse Eukaryotic Organisms, Susana Silberstein, Pallia G. Collins, Daniel J. Kelleher, Reid Gilmore

Open Access Articles

Oligosaccharyltransferase catalyzes the transfer of a preassembled high mannose oligosaccharide from a dolichol-oligosaccharide donor to consensus glycosylation acceptor sites in newly synthesized proteins in the lumen of the rough endoplasmic reticulum. The Saccharomyces cerevisiae oligosaccharyltransferase is an oligomeric complex composed of six non-identical subunits (alpha-zeta). The alpha, beta, gamma, and delta subunits of the oligosaccharyltransferase are encoded by the OST1, WBP1, OST3, and SWP1 genes, respectively. Here we describe the functional characterization of the OST2 gene that encodes the epsilon-subunit of the oligosaccharyltransferase. Genomic disruption of the OST2 locus was lethal in haploid yeast showing that expression of the Ost2 ...


Cloning And Cell Cycle Analysis Of Numa, A Phosphoprotein That Oscillates Between The Nucleus And The Mitotic Spindle, Cynthia A. Sparks Sep 1995

Cloning And Cell Cycle Analysis Of Numa, A Phosphoprotein That Oscillates Between The Nucleus And The Mitotic Spindle, Cynthia A. Sparks

GSBS Dissertations and Theses

The overall objective of this study was to identify novel proteins of the nuclear matrix in order to contribute to a better understanding of nuclear structure and organization. To accomplish this, a monoclonal antibody specific for the nuclear matrix was used to screen a human λgt11 expression library. Several cDNAs were isolated, cloned, sequenced, and shown to represent NuMA, the nuclear mitotic spindle apparatus protein. Further characterization of the gene and RNA was undertaken in an effort to obtain information about NuMA. The NuMA gene was present at a single site on human chromosome 11q13. Northern and PCR analysis of ...


Goosecoid Is Not An Essential Component Of The Mouse Gastrula Organizer But Is Required For Craniofacial And Rib Development, Jaime A. Rivera-Pérez, Moises Mallo, Maureen Gendron-Maguire, Thomas Gridley, Richard R. Behringer Sep 1995

Goosecoid Is Not An Essential Component Of The Mouse Gastrula Organizer But Is Required For Craniofacial And Rib Development, Jaime A. Rivera-Pérez, Moises Mallo, Maureen Gendron-Maguire, Thomas Gridley, Richard R. Behringer

Rivera Lab Publications

Goosecoid (gsc) is an evolutionarily conserved homeobox gene expressed in the gastrula organizer region of a variety of vertebrate embryos, including zebrafish, Xenopus, chicken and mouse. To understand the role of gsc during mouse embryogenesis, we generated gsc-null mice by gene targeting in embryonic stem cells. Surprisingly, gsc-null embryos gastrulated and formed the primary body axes; gsc-null mice were born alive but died soon after birth with numerous craniofacial defects. In addition, rib fusions and sternum abnormalities were detected that varied depending upon the genetic background. Transplantation experiments suggest that the ovary does not provide gsc function to rescue gastrulation ...


Oral Administration Of Coprostanol Producing Microorganisms To Humans To Decrease Plasma Cholesterol Concentration, Donald C. Beitz, Jerry W. Young, Ling Li, Kimberly K. Buhman Aug 1995

Oral Administration Of Coprostanol Producing Microorganisms To Humans To Decrease Plasma Cholesterol Concentration, Donald C. Beitz, Jerry W. Young, Ling Li, Kimberly K. Buhman

Iowa State University Patents

A method of decreasing plasma cholesterol is disclosed. The method includes oral administration of coprostanol-producing bacteria to humans. These organisms, once in the small intestine, will reduce free cholesterol to coprostanol, which is absorbed poorly. Pharmaceutical compositions for delivery are included as are different methods of delivery such as placing the microorganisms in food.


Mutations In Rad27 Define A Potential Link Between G₁ Cyclins And Dna Replication, Elizabeth Ann Vallen, Frederick R. Cross , '78 Aug 1995

Mutations In Rad27 Define A Potential Link Between G₁ Cyclins And Dna Replication, Elizabeth Ann Vallen, Frederick R. Cross , '78

Biology Faculty Works

The yeast Saccharomyces cerevisiae has three G1 cyclin (CLN) genes with overlapping functions. To analyze the functions of the various CLN genes, we examined mutations that result in lethality in conjunction with loss of cln1 and cln2. We have isolated alleles of RAD27/ERC11/YKL510, the yeast homolog of the gene encoding flap endonuclease 1, FEN-1.cln1 cln2 rad27/erc11 cells arrest in S phase; this cell cycle arrest is suppressed by the expression of CLN1 or CLN2 but not by that of CLN3 or the hyperactive CLN3-2. rad27/erc11 mutants are also defective in DNA damage repair, as determined ...


Functional Characterization Of Ost3p. Loss Of The 34-Kd Subunit Of The Saccharomyces Cerevisiae Oligosaccharyltransferase Results In Biased Underglycosylation Of Acceptor Substrates, Denise Karaoglu, Daniel J. Kelleher, Reid Gilmore Aug 1995

Functional Characterization Of Ost3p. Loss Of The 34-Kd Subunit Of The Saccharomyces Cerevisiae Oligosaccharyltransferase Results In Biased Underglycosylation Of Acceptor Substrates, Denise Karaoglu, Daniel J. Kelleher, Reid Gilmore

Open Access Articles

Within the lumen of the rough endoplasmic reticulum, oligosaccharyltransferase catalyzes the en bloc transfer of a high mannose oligosaccharide moiety from the lipid-linked oligosaccharide donor to asparagine acceptor sites in nascent polypeptides. The Saccharomyces cerevisiae oligosaccharyltransferase was purified as a heteroligomeric complex consisting of six subunits (alpha-zeta) having apparent molecular masses of 64 kD (Ost1p), 45 kD (Wbp1p), 34 kD, 30 kD (Swp1p), 16 kD, and 9 kD. Here we report a structural and functional characterization of Ost3p which corresponds to the 34-kD gamma-subunit of the oligosaccharyltransferase. Unlike Ost1p, Wbp1p, and Swp1p, expression of Ost3p is not essential for viability ...


In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen Jul 1995

In Vitro Expression Of Human Zona Pellucida Protein 3, Chih-Wei Chen

Theses and Dissertations in Biomedical Sciences

Human zona pellucida protein 3 (hZP3) is the putative receptor on the zona pellucida of the mature oocyte that recognizes and binds sperm, and therefore plays a critical role in fertilization.

A full length cDNA of hZP3 (1278 bp) was amplified from the human ovary mRNA by reverse transcription-polymerase chain reaction (RT-PCR). The hZP3 cDNA was subcloned into PSK and pREP4 expression vectors. The cDNA of hZP3 was further characterized by restriction mapping, PCR, auto-sequencing and Southern blot analysis by using an internal oligonucleotide probe, and found to be identical to the one reported by J. Dean. Using autosequencing, 289 ...


Investigation Of The Substrate Recognition Characteristics And Kinetics Of Mammalian Mitochondrial Dna Topoisomerase I, Zeki Topcu Jul 1995

Investigation Of The Substrate Recognition Characteristics And Kinetics Of Mammalian Mitochondrial Dna Topoisomerase I, Zeki Topcu

Theses and Dissertations in Biomedical Sciences

Topoisomerases are DNA-modifying enzymes found in prokaryotes, eukaryotes, viruses and organelles such as chloroplast and mitochondria. Information about these enzymes in eukaryotic systems is mostly limited to nuclear enzymes, although our laboratory has been characterizing the biochemical and biophysical properties of the mammalian mitochondrial topoisomerases. We have determined the polarity of the attachment of mitochondrial topoisomerase I to its substrate DNA. To study the substrate preference and kinetic parameters of mitochondrial topoisomerase I, selected regions of mammalian mitochondrial DNA (mtDNA) were inserted into pGEM plasmid vectors following a series of modification and optimization experiments of currently available methods for PCR-cloning ...


Gene Conversion During Vector Insertion In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley Jun 1995

Gene Conversion During Vector Insertion In Embryonic Stem Cells, Paul Hasty, Jaime A. Rivera-Pérez, Allan Bradley

Rivera Lab Publications

Recombination of an insertion vector into its chromosomal homologue is a conservative event in that both the chromosomal and the vector sequences are preserved. However, gene conversion may accompany homologous recombination of an insertion vector. To examine gene conversion in more detail we have determined the targeting frequencies and the structure of the recombinant alleles generated with a series of vectors which target the hprt gene in embryonic stem cells. We demonstrate that gene conversion of the introduced mutation does not significantly limit homologous recombination and that gene conversion occurs without a sequence specific bias for five different mutations. The ...


Concanavalin A-Binding Glycoconjugates In The Freshwater Sponge, Ephydatia Mulleri, Marek Janout Apr 1995

Concanavalin A-Binding Glycoconjugates In The Freshwater Sponge, Ephydatia Mulleri, Marek Janout

Life and Environmental Sciences Undergraduate Theses

This preliminary study investigated the distribution and role of cell surface carbohydrates which were suspected to affect proximal cell interactions such as recognition and adhesion. Recognition and adhesion play roles in the development of many organisms but are easily followed in freshwater sponges. The distribution of glycoconjugates in a freshwater sponge Ephydatia mulleri was investigated with the Periodic acid-Schiff (PAS) reaction and lectin histochemistry. PAS revealed the distribution of general carbohydrate in the sponge. Lectin histochemistry used Concanavalin A (ConA), a mannosebinding lectin, coupled through avidin and biotin to horseradish peroxidase enzyme (HRP) to reveal the location of mannose-containing glycoconjugates ...


A Kinetic Investigation Of The Mechanism Of Muscle Contraction With A Series Of Nucleotides, Wei Jiang Apr 1995

A Kinetic Investigation Of The Mechanism Of Muscle Contraction With A Series Of Nucleotides, Wei Jiang

Theses and Dissertations in Biomedical Sciences

Muscle contraction is thought to be accomplished by sliding of myosin filaments along actin filaments. Although actomyosin naturally uses ATP as an energy source, it can also use other nucleoside triphosphates (NTP) as substrates. In this work, the dependence of rate and equilibrium constants of the various steps in the muscle contraction mechanism upon nucleotide structure was investigated to unravel the dependence of the mechanical properties of the muscle upon changes in different biochemical steps of the mechanism.

The experiments measuring the dissociation of actomyosin by NTP (or mant-NTP) shows that both the rate constant of actomyosin-S1 dissociation and second ...


Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh Mar 1995

Enhancer Trap Technique: A Novel Tool For Identification And Developmental Characterization Of Genes Of Drosophila, Amit Singh

Biology Faculty Publications

The classical technique of mutational screen for identification of genes controlling early development has now approached saturation. A new era in genetic identification and developmental characterization of genes in Drosophila has commenced with the advent of the enhancer trap technique. This technique involves mobilization of a P-lacZ vector to diverse chromosomal locations in the fruit fly genome to bring it under the regulation of developmentally expressed genes or their enhancer elements. The technique offers a strikingly elegant method of gaining entry into fruit fly genes.


Identification And Characterization Of A Putative Telomere End-Binding Protein From Tetrahymena Thermophila, Hong Sheng, Zhen Hou, Ted Schierer, Drena L. Dobbs, Eric Henderson Mar 1995

Identification And Characterization Of A Putative Telomere End-Binding Protein From Tetrahymena Thermophila, Hong Sheng, Zhen Hou, Ted Schierer, Drena L. Dobbs, Eric Henderson

Zoology and Genetics Publications

Telomeric DNA of Tetrahymena thermophila consists of a long stretch of (TTGGGG)n double-stranded repeats with a single-stranded (TTGGGG)2 3' overhang at the end of the chromosome. We have identified and characterized a protein that specifically binds to a synthetic telomeric substrate consisting of duplex DNA and the 3' telomeric repeat overhang. This protein is called TEP (telomere end-binding protein). A change from G to A in the third position of the TTGGGG overhang repeat converts the substrate to a human telomere analog and reduces the binding affinity approximately threefold. Changing two G's to C's in the ...


Foci Of Trinucleotide Repeat Transcripts In Nuclei Of Myotonic Dystrophy Cells And Tissues, Krishan L. Taneja, Mila Mccurrach, Martin Schalling, David Housman, Robert H. Singer Mar 1995

Foci Of Trinucleotide Repeat Transcripts In Nuclei Of Myotonic Dystrophy Cells And Tissues, Krishan L. Taneja, Mila Mccurrach, Martin Schalling, David Housman, Robert H. Singer

Open Access Articles

We have analyzed the intracellular localization of transcripts from the myotonin protein kinase (Mt-PK) gene in fibroblasts and muscle biopsies from myotonic dystrophy patients and normal controls. In affected individuals, a trinucleotide expansion in the gene results in the phenotype, the severity of which is proportional to the repeat length. A fluorochrome-conjugated probe (10 repeats of CAG) hybridized specifically to this expanded repeat. Mt-PK transcripts containing CTG repeat expansions were detected in the nucleus as bright foci in DM patient fibroblasts and muscle biopsies, but not from normal individuals. These foci represented transcripts from the Mt-PK gene since they simultaneously ...


Moesin, Ezrin, And P205 Are Actin-Binding Proteins Associated With Neutrophil Plasma Membranes, K. Pestonjamasp, M. R. Amieva, C. P. Strassel, W. M. Nauseef, H. Furthmayr, Elizabeth J. Luna Mar 1995

Moesin, Ezrin, And P205 Are Actin-Binding Proteins Associated With Neutrophil Plasma Membranes, K. Pestonjamasp, M. R. Amieva, C. P. Strassel, W. M. Nauseef, H. Furthmayr, Elizabeth J. Luna

Women’s Health Research Faculty Publications

Actin-binding proteins in bovine neutrophil plasma membranes were identified using blot overlays with 125I-labeled F-actin. Along with surface-biotinylated proteins, membranes were enriched in major actin-binding polypeptides of 78, 81, and 205 kDa. Binding was specific for F-actin because G-actin did not bind. Further, unlabeled F-actin blocked the binding of 125I-labeled F-actin whereas other acidic biopolymers were relatively ineffective. Binding also was specifically inhibited by myosin subfragment 1, but not by CapZ or plasma gelsolin, suggesting that the membrane proteins, like myosin, bind along the sides of the actin filaments. The 78- and 81-kDa polypeptides were identified as moesin and ezrin ...


Pollination Of The Crown Imperial Fritillaria Imperialis By Great Tits Parus Major, Winfried S. Peters, Michael Pirl, Gerhard Gottsberger, Dieter Stefan Peters Feb 1995

Pollination Of The Crown Imperial Fritillaria Imperialis By Great Tits Parus Major, Winfried S. Peters, Michael Pirl, Gerhard Gottsberger, Dieter Stefan Peters

Winfried S. Peters

Visitations of flowers of the Crown Imperial by Great Tits at two different locations in Hessen, Germany, in 1990 and 1993 are described. The observations prove that flowers were visited because of the nectar; most likely pollination occurs during this visits. Similar reports from Europe are discussed. The significance of specific interactions including ecological generalists such as the Great Tit is considered in the context of the phylogenetic reconstruction of the development of co-adaptive syndroms.


Isolation Of A Mouse Cdna Encoding Mtj1, A New Murine Member Of The Dnaj Family Of Proteins, Shannon E. Brightman, Gregory L. Blatch, Bruce R. Zetter Feb 1995

Isolation Of A Mouse Cdna Encoding Mtj1, A New Murine Member Of The Dnaj Family Of Proteins, Shannon E. Brightman, Gregory L. Blatch, Bruce R. Zetter

Biology Faculty Publications

We report the isolation and sequencing of MTJ1, a 1792-bp cDNA from an M27 murine lung carcinoma cell line. The largest ORF within MTJ1 encodes a 63,869-Da protein, containing a 73-amino-acid (aa) sequence (the J domain) that is conserved in proteins of the DnaJ family of chaperonins. The J domain of MTJ1 is bracketed by potential transmembrane domains in a similar configuration to the J domain of the yeast DnaJ-like protein, SEC63. Polyclonal antibodies raised against deduced aa sequences within MTJ1 recognized antigens of 62, 42 and 41 kDa that were enriched in the nuclear and heavy microsome subcellular ...


An Improved Method For Chemical Devitellinization Of X-Gal Stained Drosophila Embryos, Amit Singh, Madhuri Kango-Singh, P. Sinha Feb 1995

An Improved Method For Chemical Devitellinization Of X-Gal Stained Drosophila Embryos, Amit Singh, Madhuri Kango-Singh, P. Sinha

Biology Faculty Publications

In Drosophila developmental biological studies, X-gal staining is commonly employed to study the spatio-temporal expression of the lacZ reporter gene in the transformed flies or their embryos. Study of the lacZ pattern in embryos often suffers from the lack of an efficient and high yieldirrg technique for devitellinization of X-gal stained embryos. Devitellinization techniques employed during antibody staining, in situ hybridization or embryonic cuticular preparations generally do not give satisfactory results when used for similar purpose in X-gal stained embryos. This results in the flaky appearance of the blue stain. We present here an improved chemical devitellinization technique which gives ...


The Mechanisms And Mediators Of Tooth Eruption--Models For Developmental Biologists, Sandy C. Marks Jr., Jeffrey P. Gorski, Gary E. Wise Feb 1995

The Mechanisms And Mediators Of Tooth Eruption--Models For Developmental Biologists, Sandy C. Marks Jr., Jeffrey P. Gorski, Gary E. Wise

Open Access Articles

Tooth eruption is a localized process in the jaws which exhibits precise timing and bilateral symmetry. It involves resorption and formation of bone on opposite sides of the erupting tooth and these activities depend on the dental follicle, a thin connective tissue investment of the developing and erupting tooth. Biochemical studies have shown that during eruption cells, proteins and enzymes change in the dental follicle and several growth factors and proteins known to accelerate or retard eruption have been identified. This review discusses these aspects of tooth eruption and proposes testable hypotheses and strategies that can make studies of tooth ...


The Alpha Subunit Of The Saccharomyces Cerevisiae Oligosaccharyltransferase Complex Is Essential For Vegetative Growth Of Yeast And Is Homologous To Mammalian Ribophorin I, Susana Silberstein, Pallia G. Collins, Daniel J. Kelleher, Peter J. Rapiejko, Reid Gilmore Feb 1995

The Alpha Subunit Of The Saccharomyces Cerevisiae Oligosaccharyltransferase Complex Is Essential For Vegetative Growth Of Yeast And Is Homologous To Mammalian Ribophorin I, Susana Silberstein, Pallia G. Collins, Daniel J. Kelleher, Peter J. Rapiejko, Reid Gilmore

Open Access Articles

Oligosaccharyltransferase mediates the transfer of a preassembled high mannose oligosaccharide from a lipid-linked oligosaccharide donor to consensus glycosylation acceptor sites in newly synthesized proteins in the lumen of the rough endoplasmic reticulum. The Saccharomyces cerevisiae oligosaccharyltransferase is an oligomeric complex composed of six nonidentical subunits (alpha-zeta), two of which are glycoproteins (alpha and beta). The beta and delta subunits of the oligosaccharyltransferase are encoded by the WBP1 and SWP1 genes. Here we describe the functional characterization of the OST1 gene that encodes the alpha subunit of the oligosaccharyltransferase. Protein sequence analysis revealed a significant sequence identity between the Saccharomyces cerevisiae ...


Fish Analysis On Spontaneously Arising Micronuclei In The Icf Syndrome, Michael W. Stacey, M. S. Bennett, M. Hulten Jan 1995

Fish Analysis On Spontaneously Arising Micronuclei In The Icf Syndrome, Michael W. Stacey, M. S. Bennett, M. Hulten

Bioelectrics Publications

The ICF syndrome is a rare disorder where patients show undercondensation of the heterochromatic blocks of chromosomes 1, 9, and 16 along with variable immunodeficiency. The undercondensation of the heterochromatic block appears to be restricted to a portion of PHA stimulated T cells. Patients with this syndrome also show an increase in micronuclei formation. We have used dual colour FISH to investigate the chromosomal content of these micronuclei in PHA stimulated peripheral blood cultures, an EBV transformed B cell line, and also micronuclei observed in vivo from peripheral blood smears. Chromosome 1 appears to be present in a higher proportion ...


Activation Of Transfer Rna-Guanine Ribosyltransferase By Protein Kinase C, Rana C. Morris, Bonnie J. Brooks, Panayota Eriotou, Deborah F. Kelly, Sandeep Sagar, K. Lenore Hart, Mark S. Elliot Jan 1995

Activation Of Transfer Rna-Guanine Ribosyltransferase By Protein Kinase C, Rana C. Morris, Bonnie J. Brooks, Panayota Eriotou, Deborah F. Kelly, Sandeep Sagar, K. Lenore Hart, Mark S. Elliot

Chemistry & Biochemistry Faculty Publications

Transfer RNA-guanine ribosyltransferase (TGRase) irreversibly incorporates queuine into the first position in the anticodon of four tRNA isoacceptors. Rat brain protein kinase C (PKC) was shown to stimulate rat liver TG Rase activity, TGRase preparations derived from rat liver have been observed to decrease in activity over time in storage at -20 or -70°C, Contamination of the samples by phosphatases was indicated by a p-nitrophenylphosphate conversion test, The addition of micromolar concentrations of the phosphatase inhibitors sodium pyrophosphate and sodium fluoride into TGRase isolation buffers resulted in a greater return of TGRase activity than without these inhibitors, Inactive TGRase ...


Preparation Of A Site-Specific Lymphotoxin- Mutant To Be Used In Protein Characterization And Receptor Binding Studies, Derek Andrew Knight Jan 1995

Preparation Of A Site-Specific Lymphotoxin- Mutant To Be Used In Protein Characterization And Receptor Binding Studies, Derek Andrew Knight

Theses Digitization Project

No abstract provided.


5-Fluoroorotic Acid-Selected Cell Lines And Regulation Of Ump Synthase Gene Expression In Tobacco Cells , Djoko Santoso Jan 1995

5-Fluoroorotic Acid-Selected Cell Lines And Regulation Of Ump Synthase Gene Expression In Tobacco Cells , Djoko Santoso

Retrospective Theses and Dissertations

Plant uridine-5'-monophosphate (UMP) synthase has been studied at both the biochemical and molecular levels. Using a purification procedure of salt precipitation coupled with a series of chromatography techniques, UMP synthase was purified to more than 2,000-fold from crude extracts of Cucurbita pepo L. As with UMP synthases from other higher eukaryotes, the UMP synthase of squash has both orotate phosphoribosyl transferase and orotidine-5'-monophosphate (OMP) decarboxylase activities. The molecular mass of the native UMP synthase was about 110 kDa and SDS-PAGE showed a subunit molecular mass of 50 kDa. The other biochemical properties of this UMP synthase are ...


The Role(S) Of Arginine-Specific Mono(Adp-Ribosyl)Transferase In Skeletal Muscle Cells , Hui-Yu Huang Jan 1995

The Role(S) Of Arginine-Specific Mono(Adp-Ribosyl)Transferase In Skeletal Muscle Cells , Hui-Yu Huang

Retrospective Theses and Dissertations

The overall goal of this research project was to examine the biological function of arginine-specific mono(ADP-ribosyl) transferase in skeletal muscle cells. To better understand the function of this enzyme in skeletal muscle, the experimental approach to accomplish this goal consisted of two specific objectives. The first objective was to identify the protein substrates for this enzyme in myogenic cell cultures and cellular fractions. Embryonic chick primary muscle cell cultures were used as a working system for this purpose. In membrane fractions of 96-h myotube cultures incubated with [[superscript]32 P]NAD under conditions selected for mono(ADP-ribosyl)ation, proteins ...