bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of binding‐induced changes in dynamics suggests a model for sequence‐nonspecific binding of ssDNA by replication protein A
Authors: Bhattacharya Shibani , Botuyan Maria‐Victoria , Hsu Fred , Shan Xi , Arunkumar A.I. , Arrowsmith Cheryl H. , Edwards Aled M. , Chazin Walter J. 
Published: September 2002

AbstractSingle‐stranded‐DNA‐binding proteins (SSBs) are required for numerous genetic processes ranging from DNA synthesis to the repair of DNA damage, each of which requires binding with high affinity to ssDNA of variable base composition. To gain insight into the mechanism of sequence‐nonspecific binding of ssDNA, NMR chemical shift and 15N relaxation experiments were performed on an isolated ssDNA‐binding domain (RPA70A) from the human SSB replication protein A. The backbone 13C, 15N, and 1H resonances of RPA70A were assigned for the free protein and the d‐CTTCA complex. The binding‐induced changes in backbone chemical shifts were used to map out the ssDNA‐binding site. Comparison to results obtained for the complex with d‐C5 showed that the basic mode of binding is independent of the ssDNA sequence, but that there are differences in the binding surfaces. Amide nitrogen relaxation rates (R1 and R2) and 1H–15N NOE values were measured for RPA70A in the absence and presence of d‐CTTCA. Analysis of the data using the Model‐Free formalism and spectral density mapping approaches showed that the structural changes in the binding site are accompanied by some significant changes in flexibility of the primary DNA‐binding loops on multiple timescales. On the basis of these results and comparisons to related proteins, we propose that the mechanism of sequence‐nonspecific binding of ssDNA involves dynamic remodeling of the binding surface.
Crystal structure of the ADP‐dependent glucokinase from Pyrococcus horikoshii at 2.0‐Å resolution: A large conformational change in ADP‐dependent glucokinase
Authors: Tsuge Hideaki , Sakuraba Haruhiko , Kobe Toru , Kujime Akira , Katunuma Nobuhiko , Ohshima Toshihisa 
Published: September 2002

AbstractAlthough ATP is the most common phosphoryl group donor for kinases, some kinases from certain hyperthermophilic archaea such as Pyrococcus horikoshii and Thermococcus litoralis use ADP as the phosphoryl donor. Those are ADP‐dependent glucokinases (ADPGK) and phosphofructokinases in their glycolytic pathway. Here, we succeeded in gene cloning the ADPGK from P. horikoshii OT3 (phGK) in Escherichia coli,and in easy preparation of the enzyme, crystallization, and the structure determination of the apo enzyme. Recently, the three‐dimensional structure of the ADPGK from T. litoralis (tlGK) in a complex with ADP was reported. The overall structure of two homologous enzymes (56.7%) was basically similar: This means that they consisted of large α/β‐domains and small domains. However, a marked adjustment of the two domains, which is a 10‐Å translation and a 20° rotation from the conserved GG sequence located at the center of the hinge, was observed between the apo‐phGK and ADP‐tlGK structures. The ADP‐binding loop (430–439) was disordered in the apo form. It is suggested that a large conformational change takes place during the enzymatic reaction.
Naturally Occurring Substitutions in the P/V Gene Convert the Noncytopathic Paramyxovirus Simian Virus 5 into a Virus That Induces Alpha/Beta Interferon Synthesis and Cell Death
Authors: Wansley Elizabeth K. , Parks Griffith D. 
Published: September 2002

ABSTRACT
The V protein of the paramyxovirus simian virus 5 (SV5) is responsible for targeted degradation of STAT1 and the block in alpha/beta interferon (IFN-α/β) signaling that occurs after SV5 infection of human cells. We have analyzed the growth properties of a recombinant SV5 that was engineered to be defective in targeting STAT1 degradation. A recombinant SV5 (rSV5-P/V-CPI−) was engineered to contain six naturally occurring P/V protein mutations, three of which have been shown in previous transfection experiments to disrupt the V-mediated block in IFN-α/β signaling. In contrast to wild-type (WT) SV5, human cells infected with rSV5-P/V-CPI− had STAT1 levels similar to those in mock-infected cells. Cells infected with rSV5-P/V-CPI− were found to express higher-than-WT levels of viral proteins and mRNA, suggesting that the P/V mutations had disrupted the regulation of viral RNA synthesis. Despite the inability to target STAT1 for degradation, single-step growth assays showed that the rSV5-P/V-CPI− mutant virus grew better than WT SV5 in all cell lines tested. Unexpectedly, cells infected with rSV5-P/V-CPI− but not WT SV5 showed an activation of a reporter gene that was under control of the IFN-β promoter. The secretion of IFN from cells infected with rSV5-P/V-CPI− but not WT SV5 was confirmed by a bioassay for IFN. The rSV5-P/V-CPI− mutant grew to higher titers than did WT rSV5 at early times in multistep growth assays. However, rSV5-P/V-CPI− growth quickly reached a final plateau while WT rSV5 continued to grow and produced a final titer higher than that of rSV5-P/V-CPI− by late times postinfection. In contrast to WT rSV5, infection of a variety of cell lines with rSV5-P/V-CPI− induced cell death pathways with characteristics of apoptosis. Our results confirm a role for the SV5 V protein in blocking IFN signaling but also suggest new roles for the P/V gene products in controlling viral gene expression, the induction of IFN-α/β synthesis, and virus-induced apoptosis.
Molecular Genetic Evidence that the Hydrophobic Anchors of Glycoproteins E2 and E1 Interact during Assembly of Alphaviruses
Authors: Strauss Ellen G. , Lenches Edith M. , Strauss James H. 
Published: September 2002

ABSTRACT
Chimeric alphaviruses in which the 6K and glycoprotein E1 moieties of Sindbis virus are replaced with those of Ross River virus grow very poorly, but upon passage, adapted variants arise that grow >100 times better. We have sequenced the entire domain encoding the E2, 6K, and E1 proteins of a number of these adapted variants and found that most acquired two amino acid changes, which had cumulative effects. In three independent passage series, amino acid 380 of E2, which is in the transmembrane domain, was mutated from the original isoleucine to serine in two instances and to valine once. We have now changed this residue to seven others by site-directed mutagenesis and tested the effects of these mutations on the growth of both the chimera [SIN(RRE1)] and of parental Sindbis. These results indicate that the transmembrane domains of glycoproteins E2 and E1 of alphaviruses interact in a sequence-dependent manner and that this interaction is required for efficient budding and assembly of infectious virions.
Promoter Sequences Required for Reactivation of Epstein-Barr Virus from Latency
Authors: Binné Ulrich K. , Amon Wolfgang , Farrell Paul J. 
Published: September 2002

ABSTRACT

A luciferase reporter system with stably transfected
oriP
plasmids in Akata Burkitt's lymphoma cells provides a quantitative assay for the BZLF1 Zp promoter in response to B-cell receptor (BCR) activation by cross-linking with anti-immunoglobulin. In this system, detailed kinetic studies of promoter activity are possible. Previously reported promoter elements upstream of −221 from the transcription start and the ZIIR sequence had little effect on the Zp promoter, but the ZI and ZIIIA elements were essential for early activation. The ZIIIB element mediates autoactivation. Mutation of the ZV repressor sequence greatly increased the induction of the promoter but did not make it constitutively active. Zp transcription in response to BCR cross-linking declined after a few hours; this decline was reduced and delayed by acyclovir or phosphonoacetic acid, indicating that viral DNA replication or a late viral gene can play a role in the switch off of the Zp promoter. Late expression of the LMP1 protein may account for this.
Functional Dissection of Latency-Associated Nuclear Antigen 1 of Kaposi's Sarcoma-Associated Herpesvirus Involved in Latent DNA Replication and Transcription of Terminal Repeats of the Viral Genome
Authors: Lim Chunghun , Sohn Hekwang , Lee Daeyoup , Gwack Yousang , Choe Joonho 
Published: September 2002

ABSTRACT

Latency-associated nuclear antigen 1 (LANA1) of Kaposi's sarcoma-associated herpesvirus (KSHV) is implicated in the maintenance of the viral genome during latent infection. LANA1 colocalizes with KSHV episomes on the host chromosome and mediates their maintenance by attaching these viral structures to host chromosomes. Data from long-term selection of drug resistance in cells conferred by plasmids containing the terminal repeat (TR) sequence of KSHV revealed that KSHV TRs and LANA1 act as
cis
and
trans
elements of viral latent replication, respectively. In this study, we further characterized the
cis
- and
trans
-acting elements of KSHV latent replication by using a transient replication assay with a methylation-sensitive restriction enzyme,
Dpn
I. Transient reporter and replication assays disclosed that the orientation and basal transcriptional activity of TR constructs did not significantly affect the efficiency of replication. However, at least two TR units were necessary for efficient replication. The N-terminal 90 amino acids comprising the chromosome-binding domain of LANA1 were required for the mediation of LANA1 C-terminal DNA-binding and dimerization domains to support the transient replication of KSHV TRs. LANA1 interacted with components of the origin recognition complexes (ORCs), similar to Epstein-Barr virus nuclear antigen 1. Our data suggest that LANA1 recruits ORCs to KSHV TRs for latent replication of the viral genome.
Human Immunodeficiency Virus Type 1 Nucleocapsid Protein Nuclear Localization Mediates Early Viral mRNA Expression
Authors: Zhang Jielin , Crumpacker Clyde S. 
Published: September 2002

ABSTRACT

An important aspect of the pathophysiology of human immunodeficiency virus type 1 (HIV-1) infection is the ability of the virus to replicate in the host vigorously without a latent phase and to kill cells with a dynamic turnover of 1.8 × 10
9
cells/day and 10.3 × 10
9
virions/24 h. The transcription of HIV-1 RNA in acute infection occurs at two stages; the transcription of viral spliced mRNA occurs early, and the transcription of viral genomic RNA occurs later. The HIV-1 Tat protein is translated from the early spliced mRNA and is critical for HIV-1 genomic RNA expression. The cellular transcription factors are important for HIV-1 early spliced mRNA expression. In this study we show that virion nucleocapsid protein (NC) has a role in expression of HIV-1 early spliced mRNA. The HIV-1 NC migrates from the cytoplasm to the nucleus and accumulates in the nucleus at 18 h postinfection. Mutations on HIV-1 NC zinc fingers change the pattern of early viral spliced mRNA expression and result in a delayed expression of early viral mRNA in HIV-infected cells. This delayed HIV-1 early spliced mRNA expression occurs after proviral DNA has been integrated into the cellular genome, as shown by a quantitative integration assay. These results show that virion NC plays an important role in inducing HIV-1 early mRNA expression and contributes to the rapid viral replication that occurs during HIV-1 infection.
Mammary Gland Development in Transgenic Male Mice Expressing Human P450 Aromatase
Authors: Li Xiangdong , Wärri Anni , Mäkelä Sari , Ahonen Tommi , Streng Tomi , Santti Risto , Poutanen Matti 
Published: September 2002

Abstract
We recently generated a transgenic mouse strain that expresses the human aromatase gene under the ubiquitin C promoter (AROM+). We have previously shown that in these mice the serum estradiol concentration is highly elevated, whereas the testosterone concentration is decreased. In the present study we examined mammary gland development in AROM+ male mice at different ages and found that the mammary glands of AROM+ males undergo ductal and alveolar development morphologically resembling that of terminally differentiated female mammary glands, expressing mRNA for a milk protein gene (β-casein). The male mammary glands also express multiple hormone receptors typical for female mammary gland: estrogen receptor α and β, progesterone receptor, and PRL receptor. Furthermore, data showed activation of the Stat5 (signal transducer and activator of transcription 5) signaling pathway in the AROM+ male mammary gland. Interestingly, the phenotype observed is in part reversible. Treatment with finrozole, a specific aromatase inhibitor, caused an involution of the differentiated phenotype of the mammary gland, marked by the disappearance of alveolar structures and the majority of the tertiary side branches of the ducts. The present animal model is a valuable tool for better understanding the cellular and molecular mechanisms involved in the development of gynecomastia.
Identification and Characterization of a Selective, Nonpeptide Follicle-Stimulating Hormone Receptor Antagonist
Authors: Arey Brian J. , Deecher Darlene C. , Shen Emily S. , Stevis Panayiotis E. , Meade Edwin H. , Wrobel Jay , Frail Donald E. , López Francisco J. 
Published: September 2002

AbstractThe glycoprotein hormones (LH, FSH, and TSH) are critical to the maintenance of physiological homeostasis and control of reproduction. However, despite an obvious utility for synthetic pharmacological agents, there are few reports of selective, nonpeptide agonists or antagonists to receptors for these hormones. We have identified and characterized a novel synthetic molecule capable of inhibiting the action of FSH. This compound, 7-{4-[Bis-(2-carbamoyl-ethyl)-amino]-6-chloro-(1,3,5)-triazin-2-ylamino)-4-hydroxy-3-(4-methoxy-phenylazo)-naphthalene}-2-sulfonic acid, sodium salt (compound 1), is a selective, noncompetitive inhibitor of the human (h) and rat (r) FSH receptors (FSHRs). Compound 1 selectively inhibited binding of [125I]hFSH with an IC50 value of 5.4 ± 2.3 μm. Radioligand-binding assays were performed using the baculovirus expressed extracellular domain of hFSHR (BV-tFSHR) to demonstrate site-specific interaction. Compound 1 competed for [125I]hFSH binding to BV-tFSHR with an IC50 value of 10 ± 2.8 μm. Functionally, compound 1 inhibited hFSH-induced cAMP accumulation and steroidogenesis in vitro with an IC50 value of 3 ± 0.6 μm. Competition of compound 1 for binding to other glycoprotein hormone receptors and other G protein-coupled receptors demonstrated select activity for FHSRs. Compound 1 inhibited ovulation in immature and cycling adult rats. These data provide proof of concept that selective, small molecule antagonists can be designed for glycoprotein hormone receptors.
Showing you can do it: Homework in therapy for children and adolescents with anxiety disorders
Authors: Hudson Jennifer L. , Kendall Philip C. 
Published: September 2002

AbstractThis article discusses the application of homework tasks in an empirically supported treatment for children (aged 8–13 years) with anxiety disorders. Within this program, homework tasks—through practice and rehearsal in the child's natural environment—are an important ingredient to enable the child to increase his or her mastery of the information/skills covered in each session. The homework tasks also provide an opportunity for the therapist to check the child's grasp of the session content through unassisted application of the material. This article discusses issues that arise in the application of homework tasks with a child population (e.g., compliance). Homework in both child‐ and family‐focused treatment is discussed. The issues addressed regarding homework, although raised in the context of anxious children in a cognitive behavioral treatment program, may be broadly applied to children in psychotherapy. © 2002 Wiley Periodicals, Inc. J Clin Psychol/In Session 58: 525–534, 2002.
Potential predictability of Eurasian snow cover
Authors: Schlosser C. Adam , Dirmeyer Paul A. 
Published: September 2002

AbstractPotential predictability and skill of simulated Eurasian snow cover are explored using a suite of seasonal ensemble hindcasts (i.e. retrospective forecasts), an ensemble climate simulation (spanning the years 1982–1998) and observations. Using remotely sensed observations of snow cover, we find significant point‐wise correlation over the North Atlantic and North Pacific between winter and spring averaged sea‐surface temperatures and Eurasian snow cover area. The observed correlation shows no discernible pattern related to the El Niño‐Southern Oscillation (ENSO). The hindcasts show correlation patterns similar to the observations. However, the climate simulation shows an exaggerated ENSO pattern. The results underscore the importance of initialization in seasonal climate forecasts, and that the observed potential predictability of Eurasian snowcover cannot be solely attributed to ENSO. Copyright © 2003 Royal Meteorological Society.
Electron‐dense material in the cell sall/plasma membrane interface of specialized cortical cells of peanut nodules.
Authors: Bal Arya K. 
Published: September 2002

AbstractThe nitrogen‐fixing peanut root nodules have 2‐3 layers of specialized cortical cells surrounding the infected zone. These cells are morphologically distinct from the other cortical cells due to the presence of prominent amyloplasts, lipid bodies (oleosomes), large microbodies and localized pockets of electron‐dense material at the plasma membrane‐cell wall interface. The material is resistant to solubilization by hexane and chloroform. Electron density is enhanced by p‐phenylenediamine staining and heavy metal ions such as iron, uranium and osmium. The silver proteinate staining method for suberin has shown positive results. Peroxidative activity can be demonstrated by diaminobenzidine reaction. The material appears to be proteinaceous, but could be complexed with suberin or phenolics. Although the exact nature of this material remains to be clarified, its unique position in the cells of specialized tissue of the cortex relates it to the regulation of bidirectional transport of gases and solutes during symbiosis in the root nodules.
Relationship between cell adherence and proteoglycan synthesis in cultures of human peripheral blood mononuclear cells: effects of concanavalin A.
Authors: Anastassiades T. P. , Chopra R. K. , Ford P. M. , Wood A. 
Published: September 2002

AbstractHuman, blood‐derived mononuclear cells (MC), stimulated with Concanavalin A (Con A), synthesized a chondroitin sulfate (CS) proteoglycan (PG), which was elaborated largely by T‐cells. Following Con A stimulation, the majority of MC adhered to the culture dish by day 2; but as incubation progressed to day 10 the proportion of non‐adherent (NAd) MC increased in a fashion which approximately paralleled the accumulation of PG in the medium. Cell kinetic studies suggest that, following Con A stimulation, there was an inverse relationship between the amount of newly synthesized cellular PG and adherence, which appears to be related to a reciprocal effect on PG synthesis of the declining adherent (Ad) cell density with time of culture. In the stimulated cultures, NAd cells contained much more newly synthesized CS/cell than Ad cells up to day 6 of incubation. Cell type analysis, using monoclonal antibodies against specific cell surface markers, suggested that the higher PG synthesis in the NAd population may, at least in part, be due to a greater proportion of T‐helper cells.
Bovine embryo co‐culture.
Authors: Catt James W. 
Published: September 2002

AbstractThe three methods of culturing bovine zygotes; surrogate oviducts, co‐culture and defined media are compared and contrasted. Surrogate oviducts provide the best environment and so provide a benchmark to compare in vitro culture systems. At present, co‐culture systems provide a convenient method of reliably producing embryos suitable for transfer. This is important for commercial embryo production. The use of defined media is improving and can be as efficacious as co‐culture. The advantage of defined culture systems is the ability to find the requirements of an early embryo and to tailor media to meet them. It is suggested that maturation, not zygote culture, may be the constraint in embryonic development.
The control of Ca2+ homeostasis: role of intracellular rapidly exchanging Ca2+ stores.
Authors: Villa Antonello , Meldolesi Jacopo 
Published: September 2002

ABSTRACTThe role of rapidly exchanging intracellular Ca2+ stores in the control of Ca2+ homeostasis is reviewed. The following issues are discussed: the reasons why such stores exist in eukaryotic cells; the differences between the terminal cisternae of the skeletal muscle sarcoplasmic reticulum, which have direct, physical connection with the T tubules of the plasmalemma, and the Ca2+ stores located in the depth of the cytoplasm, which are stimulated by second messengers; the cytological nature (subcompartments of the ER) of the rapidly exchanging Ca2+ stores and their functional significance. The conclusions introduce recent developments in which intracellular Ca2+ stores have been investigated also by molecular biology techniques.
THE FUNCTION OF HEAT‐SHOCK PROTEINS IN STRESS TOLERANCE
Authors: Venetianer Aniko , Pirity Melinda , Hever‐Szabo Anna 
Published: September 2002

ABSTRACTWe earlier demonstrated that hsp68 is deficiently induced upon stress in the glucocorticoid‐resistant, dedifferentiated Reuber rat hepatoma clone 2 cells, but is strongly activated in the differentiated, glucocorticoid‐sensitive Faza 967 cells from which clone 2 was derived. We used the two cell types to address the questions whether hsp68 is specifically involved in the development of thermotolerance and/or thermoresistance or drug resistance. Our experiments show that clone 2 cells were not protected from the killing effect of heat by pretreatment with sodium arsenite, whereas Faza 967 cells were. These results strongly suggest a role of hsp68 in the development of thermotolerance in hepatoma cells. Stable heat‐resistant variants of clone 2 cells were also isolated, where an increased basal expression of several hsps was observed together with the (at least partial) restoration of the heat‐inducibility of hsp68. These results suggest that several hsps are needed to protect the critical biological processes at high temperature. The heat‐resistant hepatoma cells also became resistant to several anticancer drugs. The multidrug resistance of the hepatoma variants correlates with the overexpression of the plasma membrane P‐glycoprotein. Our results showing that severely stressed hepatoma cells overexpressed the mdr gene(s) raise the possibility that the P‐gp may participate in protection against environmental stress such as heat.
Interaction of filarial proteins on growth regulation of normal lung epithelial cells in vitro
Authors: Maya A. , Usha S. , Jayaraman K. , Baba Krishnan , Sukumaran M. , Balakrishnan A. 
Published: September 2002

ABSTRACTAn in vitro model to examine the effects of filarial proteins on lung epithelial cells has been developed. Several of these proteins appear in circulation of infected individuals. A close association between tropical pulmonary eosinophilia (TPE) and filariasis has been reported by several workers. [3H]‐thymidine studies do indicate that when optimum concentration of these filarial proteins were added to lung cultures in proliferating and basal/maintenance media a further increase in growth stimulation was observed early in culture. However, on longer exposures and at higher concentrations an inhibitory effect with distinct morphological changes were noted. The dual role of these proteins on lung epithelial cells in vitro may highlight the possibility of a direct interaction of these proteins with lung cells during disease also contributing to tissue damage.