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2007

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Articles 1 - 30 of 61

Full-Text Articles in Cell Biology

Breast Cancer Cell Proliferation Is Inhibited By Bad: Regulation Of Cyclin D1, R Fernando, Js Foster, A Bible, A Ström, Rg Pestell, M Rao, Arnold Saxton, Seung Baek, K Yamaguchi, Robert Donnell, Maria Cekanova, J Wimalasena Jul 2012

Breast Cancer Cell Proliferation Is Inhibited By Bad: Regulation Of Cyclin D1, R Fernando, Js Foster, A Bible, A Ström, Rg Pestell, M Rao, Arnold Saxton, Seung Baek, K Yamaguchi, Robert Donnell, Maria Cekanova, J Wimalasena

Seung J Baek

Recent investigations suggest that functions of the proapoptotic BCL2 family members, including BAD, are not limited to regulation of apoptosis. Here we demonstrate that BAD inhibits G(1) to S phase transition in MCF7 breast cancer cells independent of apoptosis. BAD overexpression inhibited G(1) transit and cell growth as well as cyclin D1 expression. Inhibition of cyclin D1 expression was mediated through inhibition of transcription activated by AP1. Chromatin immunoprecipitation assays indicated that BAD is localized at the 12-O-tetradecanoylphorbol-13-acetate-response element (TRE) and cAMP-response element (CRE) in the cyclin D1 promoter. This was shown to reflect direct binding interactions of ...


Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom Dec 2007

Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom

Open Dartmouth: Faculty Open Access Scholarship

Candida albicans is an opportunistic human fungal pathogen that causes systemic candidiasis as well as superficial mucosal candidiasis. In response to the host environment, C. albicans transitions between yeast and hyphal forms. In particular, hyphal growth is important in facilitating adhesion and invasion of host tissues, concomitant with the expression of various hypha-specific virulence factors. In previous work, we showed that the cyclic AMP (cAMP) signaling pathway plays a crucial role in morphogenic transitions and virulence of C. albicans by studying genes encoding adenylate cyclase-associated protein (CAP1) and high-affinity phosphodiesterase (PDE2) (Y. S. Bahn, J. Staab, and P. Sundstrom, Mol ...


Expression And Characterization Of The Flocculin Flo11/Muc1, A Yeast Mannoprotein With Homotypic Properties Of Adhesion, Li Li Ph.D., Lois M. Douglas, Yang Yang, A M. Dranginis Dec 2007

Expression And Characterization Of The Flocculin Flo11/Muc1, A Yeast Mannoprotein With Homotypic Properties Of Adhesion, Li Li Ph.D., Lois M. Douglas, Yang Yang, A M. Dranginis

Faculty Works: Biology, Chemistry, and Environmental Studies

The Flo11/Muc1 flocculin has diverse phenotypic effects. Saccharomyces cerevisiae cells of strain background Σ1278b require Flo11p to form pseudohyphae, invade agar, adhere to plastic, and develop biofilms, but they do not flocculate. We show that S. cerevisiae var. diastaticusstrains, on the other hand, exhibit Flo11-dependent flocculation and biofilm formation but do not invade agar or form pseudohyphae. In order to study the nature of the Flo11p proteins produced by these two types of strains, we examined secreted Flo11p, encoded by a plasmid-borne gene, in which the glycosylphosphatidylinositol anchor sequences had been replaced by a histidine tag. A protein ...


A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith Nov 2007

A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith

Open Dartmouth: Faculty Open Access Scholarship

For virtually all cilia and eukaryotic flagella, the second messengers calcium and cyclic adenosine monophosphate are implicated in modulating dynein- driven microtubule sliding to regulate beating. Calmodulin (CaM) localizes to the axoneme and is a key calcium sensor involved in regulating motility. Using immunoprecipitation and mass spectrometry, we identify members of a CaM-containing complex that are involved in regulating dynein activity. This complex includes flagellar-associated protein 91 (FAP91), which shares considerable sequence similarity to AAT-1, a protein originally identified in testis as an A-kinase anchor protein (AKAP)- binding protein. FAP91 directly interacts with radial spoke protein 3 (an AKAP), which ...


Supervillin Slows Cell Spreading By Facilitating Myosin Ii Activation At The Cell Periphery, Norio Takizawa, Reiko Ikebe, Mitsuo Ikebe, Elizabeth J. Luna Oct 2007

Supervillin Slows Cell Spreading By Facilitating Myosin Ii Activation At The Cell Periphery, Norio Takizawa, Reiko Ikebe, Mitsuo Ikebe, Elizabeth J. Luna

Open Access Articles

During cell migration, myosin II modulates adhesion, cell protrusion and actin organization at the leading edge. We show that an F-actin- and membrane-associated scaffolding protein, called supervillin (SV, p205), binds directly to the subfragment 2 domains of nonmuscle myosin IIA and myosin IIB and to the N-terminus of the long form of myosin light chain kinase (L-MLCK). SV inhibits cell spreading via an MLCK- and myosin II-dependent mechanism. Overexpression of SV reduces the rate of cell spreading, and RNAi-mediated knockdown of endogenous SV increases it. Endogenous and EGFP-tagged SV colocalize with, and enhance the formation of, cortical bundles of F-actin ...


Suppression Of P53-Dependent Senescence By The Jnk Signal Transduction Pathway, Madhumita Das, Feng Jiang, Hayla Karen Sluss, Chao Zhang, Kevan M. Shokat, Richard A. Flavell, Roger J. Davis Oct 2007

Suppression Of P53-Dependent Senescence By The Jnk Signal Transduction Pathway, Madhumita Das, Feng Jiang, Hayla Karen Sluss, Chao Zhang, Kevan M. Shokat, Richard A. Flavell, Roger J. Davis

Open Access Articles

The JNK signaling pathway is implicated in the regulation of the AP1 transcription factor and cell proliferation. Here, we examine the role of JNK by using conditional and chemical genetic alleles of the ubiquitously expressed murine genes that encode the isoforms JNK1 and JNK2. Our analysis demonstrates that JNK is not essential for proliferation. However, JNK is required for expression of the cJun and JunD components of the AP1 transcription factor, and JNK-deficient cells exhibit early p53-dependent senescence. These data demonstrate that JNK can act as a negative regulator of the p53 tumor suppressor.


Role Of Actin Cytoskeletal Dynamics In Activation Of The Cyclic Amp Pathway And Hwp1 Gene Expression In Candida Albicans, Michael J. Wolyniak, Paula Sundstrom Oct 2007

Role Of Actin Cytoskeletal Dynamics In Activation Of The Cyclic Amp Pathway And Hwp1 Gene Expression In Candida Albicans, Michael J. Wolyniak, Paula Sundstrom

Open Dartmouth: Faculty Open Access Scholarship

Changes in gene expression during reversible bud-hypha transitions of the opportunistic fungal pathogen Candida albicans permit adaptation to environmental conditions that are critical for proliferation in host tissues. Our previous work has shown that the hypha-specific adhesin gene HWP1 is up-regulated by the cyclic AMP (cAMP) signaling pathway. However, little is known about the potential influences of determinants of cell morphology on HWP1 gene expression. We found that blocking hypha formation with cytochalasin A, which destabilizes actin filaments, and with latrunculin A, which sequesters actin monomers, led to a loss of HWP1 gene expression. In contrast, high levels of HWP1 ...


Mutations Affecting A Putative Mutla Endonuclease Motif Impact Multiple Dna Mismatch Repair Functions, Naz Erdeniz, Megan Nguyen, Suzanne M. Deschênes, R. Michael Liskay Oct 2007

Mutations Affecting A Putative Mutla Endonuclease Motif Impact Multiple Dna Mismatch Repair Functions, Naz Erdeniz, Megan Nguyen, Suzanne M. Deschênes, R. Michael Liskay

Biology Faculty Publications

Mutations in DNA mismatch repair (MMR) lead to increased mutation rates and higher recombination between similar, but not identical sequences, as well as resistance to certain DNA methylating agents. Recently, a component of human MMR machinery, MutLα, has been shown to display a latent endonuclease activity. The endonuclease active site appears to include a conserved motif, DQHA(X)2E(X)4E, within the COOH-terminus of human PMS2. Substitution of the glutamic acid residue (E705) abolished the endonuclease activity and mismatch-dependent excision in vitro. Previously, we showed that the PMS2-E705K mutation and the corresponding mutation in Saccharomyces cerevisiae ...


C-Jun N-Terminal Kinase 1 Is Required For Toll-Like Receptor 1 Gene Expression In Macrophages, Hooman Izadi, Amirreza T. Motameni, Tonya C. Bates, Elias R. Olivera, Vega Villar-Suarez, Ila Joshi, Renu Garg, Barbara A. Osborne, Roger J. Davis, Mercedes Rincon, Juan Anguita Oct 2007

C-Jun N-Terminal Kinase 1 Is Required For Toll-Like Receptor 1 Gene Expression In Macrophages, Hooman Izadi, Amirreza T. Motameni, Tonya C. Bates, Elias R. Olivera, Vega Villar-Suarez, Ila Joshi, Renu Garg, Barbara A. Osborne, Roger J. Davis, Mercedes Rincon, Juan Anguita

Davis Lab Publications

The regulation of innate immune responses to pathogens occurs through the interaction of Toll-like receptors (TLRs) with pathogen-associated molecular patterns and the activation of several signaling pathways whose contribution to the overall innate immune response to pathogens is poorly understood. We demonstrate a mechanism of control of murine macrophage responses mediated by TLR1/2 heterodimers through c-Jun N-terminal kinase 1 (JNK1) activity. JNK controls tumor necrosis factor alpha production and TLR-mediated macrophage responses to Borrelia burgdorferi, the causative agent of Lyme disease, and the TLR1/TLR2-specific agonist PAM(3)CSK(4). JNK1, but not JNK2, activity regulates the expression of ...


Breast Cancer Cell Proliferation Is Inhibited By Bad: Regulation Of Cyclin D1, R Fernando, Js Foster, A Bible, A Ström, Rg Pestell, M Rao, Arnold Saxton, Seung Baek, K Yamaguchi, Robert Donnell, Maria Cekanova, J Wimalasena Sep 2007

Breast Cancer Cell Proliferation Is Inhibited By Bad: Regulation Of Cyclin D1, R Fernando, Js Foster, A Bible, A Ström, Rg Pestell, M Rao, Arnold Saxton, Seung Baek, K Yamaguchi, Robert Donnell, Maria Cekanova, J Wimalasena

Maria Cekanova MS, RNDr, PhD

Recent investigations suggest that functions of the proapoptotic BCL2 family members, including BAD, are not limited to regulation of apoptosis. Here we demonstrate that BAD inhibits G(1) to S phase transition in MCF7 breast cancer cells independent of apoptosis. BAD overexpression inhibited G(1) transit and cell growth as well as cyclin D1 expression. Inhibition of cyclin D1 expression was mediated through inhibition of transcription activated by AP1. Chromatin immunoprecipitation assays indicated that BAD is localized at the 12-O-tetradecanoylphorbol-13-acetate-response element (TRE) and cAMP-response element (CRE) in the cyclin D1 promoter. This was shown to reflect direct binding interactions of ...


Requirement Of Jip Scaffold Proteins For Nmda-Mediated Signal Transduction, Norman J. Kennedy, Gilles Martin, Anka G. Ehrhardt, Julie Cavanagh-Kyros, Chia-Yi Kuan, Pasko Rakic, Richard A. Flavell, Steven N. Treistman, Roger J. Davis Sep 2007

Requirement Of Jip Scaffold Proteins For Nmda-Mediated Signal Transduction, Norman J. Kennedy, Gilles Martin, Anka G. Ehrhardt, Julie Cavanagh-Kyros, Chia-Yi Kuan, Pasko Rakic, Richard A. Flavell, Steven N. Treistman, Roger J. Davis

Davis Lab Publications

JIP scaffold proteins are implicated in the regulation of protein kinase signal transduction pathways. To test the physiological role of these scaffold proteins, we examined the phenotype of compound mutant mice that lack expression of JIP proteins. These mice were found to exhibit severe defects in N-methyl-D-aspartic acid (NMDA) receptor function, including decreased NMDA-evoked current amplitude, cytoplasmic Ca(++), and gene expression. The decreased NMDA receptor activity in JIP-deficient neurons is associated with reduced tyrosine phosphorylation of NR2 subunits of the NMDA receptor. JIP complexes interact with the SH2 domain of cFyn and may therefore promote tyrosine phosphorylation and activity of ...


Defining Early Steps In Mrna Transport: Mutant Mrna In Myotonic Dystrophy Type I Is Blocked At Entry Into Sc-35 Domains, Kelly P. Smith, Meg Byron, Carol V. Johnson, Yigong P. Xing, Jeanne B. Lawrence Sep 2007

Defining Early Steps In Mrna Transport: Mutant Mrna In Myotonic Dystrophy Type I Is Blocked At Entry Into Sc-35 Domains, Kelly P. Smith, Meg Byron, Carol V. Johnson, Yigong P. Xing, Jeanne B. Lawrence

Open Access Articles

In myotonic dystrophy type 1 (DM1), triplet repeat expansion in the 3' untranslated region of dystrophia myotonica protein kinase (DMPK) causes the nuclear retention of mutant messenger RNA (mRNA). Although the DMPK gene locus positions precisely at the outer edge of a factor-rich SC-35 domain, the normal mRNA consistently accumulates within the domain, and this RNA is depleted upon transcriptional inhibition. In DM1, mutant transcripts detach from the gene but accumulate in granules that abut but do not enter SC-35 domains, suggesting that RNA entry into the domain is blocked. Despite their exclusion from these compartments, mutant transcripts are spliced ...


Structural Insights Into The Interaction Of The Evolutionarily Conserved Zpr1 Domain Tandem With Eukaryotic Ef1a, Receptors, And Smn Complexes, Ashwini K. Mishra, Laxman Gangwani, Roger J. Davis, David G. Lambright Aug 2007

Structural Insights Into The Interaction Of The Evolutionarily Conserved Zpr1 Domain Tandem With Eukaryotic Ef1a, Receptors, And Smn Complexes, Ashwini K. Mishra, Laxman Gangwani, Roger J. Davis, David G. Lambright

Open Access Articles

Eukaryotic genomes encode a zinc finger protein (ZPR1) with tandem ZPR1 domains. In response to growth stimuli, ZPR1 assembles into complexes with eukaryotic translation elongation factor 1A (eEF1A) and the survival motor neurons protein. To gain insight into the structural mechanisms underlying the essential function of ZPR1 in diverse organisms, we determined the crystal structure of a ZPR1 domain tandem and characterized the interaction with eEF1A. The ZPR1 domain consists of an elongation initiation factor 2-like zinc finger and a double-stranded beta helix with a helical hairpin insertion. ZPR1 binds preferentially to GDP-bound eEF1A but does not directly influence the ...


The Yeast Integral Membrane Protein Apq12 Potentially Links Membrane Dynamics To Assembly Of Nuclear Pore Complexes, John J. Scarcelli, Christin A. Hodge, Charles N. Cole Aug 2007

The Yeast Integral Membrane Protein Apq12 Potentially Links Membrane Dynamics To Assembly Of Nuclear Pore Complexes, John J. Scarcelli, Christin A. Hodge, Charles N. Cole

Open Dartmouth: Faculty Open Access Scholarship

Although the structure and function of components of the nuclear pore complex (NPC) have been the focus of many studies, relatively little is known about NPC biogenesis. In this study, we report that Apq12 is required for efficient NPC biogenesis in Saccharomyces cerevisiae. Apq12 is an integral membrane protein of the nuclear envelope (NE) and endoplasmic reticulum. Cells lacking Apq12 are cold sensitive for growth, and a subset of their nucleoporins (Nups), those that are primarily components of the cytoplasmic fibrils of the NPC, mislocalize to the cytoplasm. APQ12 deletion also causes defects in NE morphology. In the absence of ...


Vitamin E (Tocotrienols) And Prostate Cancer: A Proteomics Approach., Christian Mbangha Muenyi Aug 2007

Vitamin E (Tocotrienols) And Prostate Cancer: A Proteomics Approach., Christian Mbangha Muenyi

Electronic Theses and Dissertations

Proteomics is the large scale study of proteins in cells or organisms. The purpose of this study was to characterize the proteomic alterations occurring in a prostate cancer (LNCaP) cell line after treatment with delta-tocotrienol (a form of vitamin E not very prevalent from most dietary sources). We found that both gamma- and delta-tocotrienols induced time and concentration dependent growth inhibition and programmed cell dead (apoptosis) in LNCaP cells. Secondly, we used two-dimensional gel electrophoresis (2-DE) to characterize changes in protein expression levels associated with this treatment. Our results show that a specific set of proteins are regulated at both ...


Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel Jul 2007

Regulation Of Meiotic Cohesion And Chromosome Core Morphogenesis During Pachytene In Drosophila Oocytes, Radhika S. Khetani, Sharon E. Bickel

Open Dartmouth: Faculty Open Access Scholarship

During meiosis, cohesion between sister chromatids is required for normal levels of homologous recombination, maintenance of chiasmata and accurate chromosome segregation during both divisions. In Drosophila, null mutations in the ord gene abolish meiotic cohesion, although how ORD protein promotes cohesion has remained elusive. We show that SMC subunits of the cohesin complex colocalize with ORD at centromeres of ovarian germ-line cells. In addition, cohesin SMCs and ORD are visible along the length of meiotic chromosomes during pachytene and remain associated with chromosome cores following DNase I digestion. In flies lacking ORD activity, cohesin SMCs fail to accumulate at oocyte ...


Water. New Waters And New Life, Juan Enriquez Jul 2007

Water. New Waters And New Life, Juan Enriquez

New England Journal of Public Policy

An excerpt from an article about life sciences taken from the proceedings of the Education for Public Inquiry and International Citizenship (EPIIC) Symposium held at Tufts University in Massachusetts in February 2005 is presented.


Comparative Functional Analysis Of Aquaporins/Glyceroporins In Mammals And Anurans, Carissa M. Krane, David L. Goldstein Jul 2007

Comparative Functional Analysis Of Aquaporins/Glyceroporins In Mammals And Anurans, Carissa M. Krane, David L. Goldstein

Biology Faculty Publications

Maintenance of fluid homeostasis is critical to establishing and maintaining normal physiology. The landmark discovery of membrane water channels (aquaporins; AQPs) ushered in a new area in osmoregulatory biology that has drawn from and contributed to diverse branches of biology, from molecular biology and genomics to systems biology and evolution, and from microbial and plant biology to animal and translational physiology. As a result, the study of AQPs provides a unique and integrated backdrop for exploring the relationships between genes and genome systems, the regulation of gene expression, and the physiologic consequences of genetic variation. The wide species distribution of ...


Tailed Forisomes Of Canavalia Gladiata: A New Model To Study Ca2+-Driven Protein Contractility, Winfried Peters, Michael Knoblauch, Stephen Warmann, Reinhard Schnetter, Amy Shen, William Pickard Jun 2007

Tailed Forisomes Of Canavalia Gladiata: A New Model To Study Ca2+-Driven Protein Contractility, Winfried Peters, Michael Knoblauch, Stephen Warmann, Reinhard Schnetter, Amy Shen, William Pickard

Winfried S. Peters

Background and Aims Forisomes are Ca2+-dependent contractile protein bodies that form reversible plugs in sieve tubes of faboid legumes. Previous work employed Vicia faba forisomes, a not entirely unproblematic experimental system. The aim of this study was to seek to establish a superior model to study these intriguing actuators.
Methods Existing isolation procedures were modified to study the exceptionally large, tailed forisomes of Canavalia gladiata by differential interference contrast microscopy in vitro. To analyse contraction/expansion kinetics quantitatively, a geometric model was devised which enabled the computation of time-courses of derived parameters such as forisome volume from simple parameters ...


Somatostatin Receptor Subtype 2 Is Functionally Expressed In Raw264.7 Cells, Matthew Sung Jun 2007

Somatostatin Receptor Subtype 2 Is Functionally Expressed In Raw264.7 Cells, Matthew Sung

Seton Hall University Dissertations and Theses (ETDs)

Chronic inflammation left unchecked can be quite harmful to the tissue with the pro-inflammatory stimulus. It is marked by the recruitment and activation of leukocytes, including lymphocytes and macrophages with their subsequent proliferation and reactive oxygen species release. Macrophages are also one of the primary players in propagating the inflammatory response as they secrete pro-inflammatory cytokines to sustain local tissue responses. Current therapies for chronic inflammation include non-steroidal anti­ inflammatory drugs and glucocorticoids; however, both have various side effects and setbacks. Somatostatin is an endogenous hormone which inhibits cellular secretion and proliferation throughout the body. Somatostatin receptor activation is mediated ...


The E705k Mutation In Hpms2 Exerts Recessive, Not Dominant, Effects On Mismatch Repair, Suzanne M. Deschênes, Guy Tomer, Megan Nguyen, Naz Erdeniz, Nicole C. Juba, Natalia Sepúlveda, Jenna E. Pisani, R. Michael Liskay May 2007

The E705k Mutation In Hpms2 Exerts Recessive, Not Dominant, Effects On Mismatch Repair, Suzanne M. Deschênes, Guy Tomer, Megan Nguyen, Naz Erdeniz, Nicole C. Juba, Natalia Sepúlveda, Jenna E. Pisani, R. Michael Liskay

Biology Faculty Publications

The hPMS2 mutation E705K is associated with Turcot syndrome. To elucidate the pathogenesis of hPMS2-E705K, we modeled this mutation in yeast and characterized its expression and effects on mutation avoidance in mammalian cells. We found that while hPMS2-E705K (pms1-E738K in yeast) did not significantly affect hPMS2 (Pms1p in yeast) stability or interaction with MLH1, it could not complement the mutator phenotype in MMR-deficient mouse or yeast cells. Furthermore, hPMS2-E705K/pms1-E738K inhibited MMR in wild-type (WT) mammalian cell extracts or yeast cells only when present in excess amounts relative to WT PMS2. Our results strongly suggest that hPMS2-E705K is a recessive ...


Somatostatin Receptors Signal Through Efa6a-Arf6 To Activate Phospholipase D In Clonal Β-Cells, Justin A. Grodnitzky, Nasser Syed, Michael J. Kimber, Tim A. Day, Julie G. Donaldson, Walter H. Hsu May 2007

Somatostatin Receptors Signal Through Efa6a-Arf6 To Activate Phospholipase D In Clonal Β-Cells, Justin A. Grodnitzky, Nasser Syed, Michael J. Kimber, Tim A. Day, Julie G. Donaldson, Walter H. Hsu

Biomedical Sciences Publications

Somatostatin (SS) is a peptide hormone that inhibits insulin secretion in β-cells by activating its Gi/o-coupled receptors. Our previous work indicated that a βγ-dimer of Gi/o coupled to SS receptors can activate phospholipase D1 (PLD1) (Cheng, H., Grodnitzky, J. A., Yibchok-anun, S., Ding, J., and Hsu, W. H. (2005) Mol. Pharmacol. 67, 2162–2172). The aim of the present study was to elucidate the mechanisms underlying SS-induced PLD activation. We demonstrated the presence of ADP-ribosylation factor Arf1 and Arf6 in clonal β-cells, HIT-T15. We also determined that the activation of PLD1 was mediated through Arf6 ...


Cross-Bridge Kinetics Of Cardiac Myofibrils Carrying Myopathy-Causing Mutation, Disha Dumka M.S. May 2007

Cross-Bridge Kinetics Of Cardiac Myofibrils Carrying Myopathy-Causing Mutation, Disha Dumka M.S.

Theses and Dissertations

Dumka, Disha., Cross-bridge kinetics of cardiac myofibrils carrying myopathy-causing mutation. Doctor of Philosophy (Biochemistry and Molecular Biology), May 2007, 98 pp., 8 tables, 23 illustrations, and bibliography: 102 titles. Familial hypertrophic cardiomyopathy is a disease characterized by left ventricular hypertrophy and myofibrillar disarray. It is caused by mutations in sarcomeric proteins, including the ventricular isoform of myosin regulatory light chain (RLC). We have focused on one particular mutation of RLC-substitution of glutamic acid (E) at position 22 for lysine (K). The E22k mutation is located in the RLC Ca2+ -binding site. Earlier work has demonstrated that phosphorylation and Ca2+ binding ...


Reversible Birefringence Suggests A Role For Molecular Self-Assembly In Forisome Contractility, Winfried Peters, Reinhard Schnetter, Michael Knoblauch Apr 2007

Reversible Birefringence Suggests A Role For Molecular Self-Assembly In Forisome Contractility, Winfried Peters, Reinhard Schnetter, Michael Knoblauch

Winfried S. Peters

Forisomes are contractile protein bodies that control the effective diameter of the sieve elements of the faboid legumes by reversible, Ca2+-driven changes of shape. Forisomes consist of fibrils; we inferred from available electron-microscopical data (which necessarily provide images of fixed, non-functional forisomes) that a reversible assembly of ordered fibrillar arrays might be involved in the contractile mechanism. Here we examined functional forisomes isolated from Vicia faba L. by differential interference contrast microscopy and polarisation microscopy. We found them birefringent in the longitudinally expanded but not in the contracted state, showing ‘parallel extinction’ with the direction of vibration of the ...


Stability Of Eukaryotic Elongation Factor One Alpha Protein In The Cell, Jennifer Watry Apr 2007

Stability Of Eukaryotic Elongation Factor One Alpha Protein In The Cell, Jennifer Watry

Honors Theses

Eukaryotic Elongation Factor One Alpha (eEF1A) is an abundant protein found in every cell of every organism and is involved in functions concerning protein synthesis and degradation, the cytoskeleton, and signaling. How these functions are regulated is not yet understood for this protein. Regulation of the protein may be controlled by transcription of the genes encoding the protein or the stability and modification of the protein. The goal of this project was to determine the stability of eEf1A proteins in Arabidopsis thaliana. Protein stability was determined by treating tissues with cycloheximide, an inhibitor of protein synthesis. Gel electrophoresis and western ...


Involvement Of Plekhm1 In Osteoclastic Vesicular Transport And Osteopetrosis In Incisors Absent Rats And Humans, Liesbeth Van Wesenbeeck, Paul R. Odgren, Fraser P. Coxon, Annalisa Frattini, Pierre Moens, Bram Perdu, Carole A. Mackay, Els Van Hul, Jean-Pierre Timmermans, Filip Vanhoenacker, Ruben Jacobs, Barbara Peruzzi, Anna Teti, Miep H. Helfrich, Michael J. Rogers, Anna Villa, Wim Van Hul Apr 2007

Involvement Of Plekhm1 In Osteoclastic Vesicular Transport And Osteopetrosis In Incisors Absent Rats And Humans, Liesbeth Van Wesenbeeck, Paul R. Odgren, Fraser P. Coxon, Annalisa Frattini, Pierre Moens, Bram Perdu, Carole A. Mackay, Els Van Hul, Jean-Pierre Timmermans, Filip Vanhoenacker, Ruben Jacobs, Barbara Peruzzi, Anna Teti, Miep H. Helfrich, Michael J. Rogers, Anna Villa, Wim Van Hul

Odgren Lab Publications

This study illustrates that Plekhm1 is an essential protein for bone resorption, as loss-of-function mutations were found to underlie the osteopetrotic phenotype of the incisors absent rat as well as an intermediate type of human osteopetrosis. Electron and confocal microscopic analysis demonstrated that monocytes from a patient homozygous for the mutation differentiated into osteoclasts normally, but when cultured on dentine discs, the osteoclasts failed to form ruffled borders and showed little evidence of bone resorption. The presence of both RUN and pleckstrin homology domains suggests that Plekhm1 may be linked to small GTPase signaling. We found that Plekhm1 colocalized with ...


Short Telomeres In Short-Lived Males: What Are The Molecular And Evolutionary Causes?, Stephanie Jemielity, Masayuki Kimura, Karen M. Parker, Joel D. Parker, Xiaojian Cao, Abraham Aviv, Laurent Keller Apr 2007

Short Telomeres In Short-Lived Males: What Are The Molecular And Evolutionary Causes?, Stephanie Jemielity, Masayuki Kimura, Karen M. Parker, Joel D. Parker, Xiaojian Cao, Abraham Aviv, Laurent Keller

Joel D Parker

Telomere length regulation is an important aspect of cell maintenance in eukaryotes, since shortened telomeres can lead to a number of defects, including impaired cell division. Although telomere length is correlated with lifespan in some bird species, its possible role in aging and lifespan determination is still poorly understood. Here we investigate telomere dynamics (changes in telomere length and attrition rate) and telomerase activity in the ant Lasius niger, a species in which different groups of individuals have evolved extraordinarily different lifespans. We found that somatic tissues of the short-lived males had dramatically shorter telomeres than those of the much ...


Engineering An Improved Expression Vector For The Nupl53 Rna Binding Domain, Francisca Maertens Apr 2007

Engineering An Improved Expression Vector For The Nupl53 Rna Binding Domain, Francisca Maertens

Life and Environmental Sciences Undergraduate Theses

The nucleoporin Nupl53 has a critical role in both import and export of cellular substances across the nuclear envelope. A unique RNA binding domain has been revealed in Nupl53 (Nupl53-RBD). In order to further understand the interaction between the RNA binding domain (RBD) of Nupl53 and RNA, a crystal structure of the domain would be invaluable. This can be accomplished only if a significant quantity of purified RBD is isolated. Several RBD constructs have been produced to aid in purification of this protein. In most cases, recombinant RBD preparations are fairly heterogeneous and thus unsuitable for structural studies. However, a ...


A 368-Base-Pair Cis-Acting Hwp1 Promoter Region, Hcr, Of Candida Albicans Confers Hypha-Specific Gene Regulation And Binds Architectural Transcription Factors Nhp6 And Gcf1p, Samin Kim, Michael J. Wolyniak, Janet F. Staab, Paula Sundstrom Apr 2007

A 368-Base-Pair Cis-Acting Hwp1 Promoter Region, Hcr, Of Candida Albicans Confers Hypha-Specific Gene Regulation And Binds Architectural Transcription Factors Nhp6 And Gcf1p, Samin Kim, Michael J. Wolyniak, Janet F. Staab, Paula Sundstrom

Open Dartmouth: Faculty Open Access Scholarship

To elucidate the molecular mechanisms controlling the expression of the hypha-specific adhesin gene HWP1 of Candida albicans, its promoter was dissected and analyzed using a green fluorescent protein reporter gene. A 368-bp region, the HWP1 control region (HCR), was critical for activation under hypha-inducing conditions and conferred developmental regulation to a heterologous ENO1 promoter. A more distal region of the promoter served to amplify the level of promoter activation. Using gel mobility shift assays, a 249-bp subregion of HCR, HCRa, was found to bind at least four proteins from crude extracts of yeasts and hyphae with differing binding patterns dependent ...


The Tripartite Motif (Trim) Of Nuclear Factor 7 Is Required For Its Association With Transcription Units, Brent Beenders, Peter L. Jones, Michel Bellini Apr 2007

The Tripartite Motif (Trim) Of Nuclear Factor 7 Is Required For Its Association With Transcription Units, Brent Beenders, Peter L. Jones, Michel Bellini

Peter Jones Lab Publications

In amphibian oocytes, the maternal nuclear factor NF7 associates with the elongating pre-mRNAs present on the numerous lateral loops of the lampbrush chromosomes. Here, we have purified NF7 from an oocyte extract by using a combination of ion-exchange chromatography and gel filtration chromatography and demonstrated for the first time that nucleoplasmic NF7 exists primarily as free homotrimers. We confirmed the in vivo homotrimerization of NF7 by using a glutaraldehyde cross-linking assay, and we further showed that it only requires the coiled-coil domain of the NF7 tripartite motif/RBCC motif. Interestingly, we also obtained evidence that NF7 is recruited to the ...