bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequence Elements in both the Intergenic Space and the 3′ Untranslated Region of the
Crithidia fasciculata KAP3
Gene Are Required for Cell Cycle Regulation of
KAP3
mRNA
Authors: Avliyakulov Nuraly K. , Hines Jane C. , Ray Dan S. 
Published: August 2003

ABSTRACT

mRNA levels of several
Crithidia fasciculata
genes involved in DNA metabolism have previously been found to cycle as cells progress through the cell cycle. Octamer consensus sequences in the 5′ untranslated regions (5′ UTRs) of these transcripts were shown to be required for cycling of these mRNAs. The
KAP3
gene encodes a kinetoplast histone H1-like DNA binding protein, and its mRNA levels cycle in parallel with those of the kinetoplast DNA topoisomerase (TOP2), dihydrofolate reductase-thymidylate synthase (DHFR-TS), and the large subunit of the nuclear single-stranded DNA binding protein (RPA1).
KAP3
mRNA contains two octamer consensus sequences in its 3′ UTR but none in its 5′ UTR. Mutation of these octamer sequences was not sufficient to prevent cycling of a sequence-tagged
KAP3
mRNA expressed from a plasmid. Mutation of an octamer sequence contained on the precursor transcript but not on the mRNA, in addition to mutation of the two octamer sequences in the 3′ UTR, was necessary to abolish cycling of the mRNA. The requirement for a sequence not present on the mature mRNA indicates that regulation of the mRNA levels by the octamer sequences occurs at or prior to splicing of the transcript. Incompletely processed RNAs containing octamer sequences were also found to accumulate during the cell cycle when the mRNA levels were lowest. These RNA species hybridize to both the
KAP3
coding sequence and that of the downstream drug resistance gene, indicating a lack of processing within the intergenic region separating these genes. We propose a cell cycle-dependent interference in transcript processing mediated by octamer consensus sequences as a mechanism contributing to the cycling of such transcripts.
Environmental Suppression of
Neurospora crassa cot-1
Hyperbranching: a Link between COT1 Kinase and Stress Sensing
Authors: Gorovits Rena , Yarden Oded 
Published: August 2003

ABSTRACT

cot-1
mutants belong to a class of
Neurospora crassa
colonial temperature-sensitive (
cot
) mutants that exhibit abnormal polar extension and branching patterns when grown at restrictive temperatures.
cot-1
encodes a Ser/Thr protein kinase that is structurally related to the human myotonic dystrophy kinase which, when impaired, confers a disease that involves changes in cytoarchitecture and ion homeostasis. When grown under restrictive conditions,
cot-1
cultures exhibited enhanced medium acidification rates, increased relative abundance of sodium, and increased intracellular glycerol content, indicating an ion homeostasis defect in a hyperbranching mutant. The application of ion transport blockers led to only mild suppression of the
cot-1
phenotype. The presence of increased medium NaCl or sorbitol, H
2
O
2
, or ethanol levels significantly suppressed the
cot-1
phenotype, restored ion homeostasis, and was accompanied by reduced levels of cyclic AMP-dependent protein kinase (PKA) activity. The
cot-1
phenotype could also be partially suppressed by direct inhibition of PKA with KT-5720. A reduced availability of fermentable carbon sources also had a suppressive effect on the
cot-1
phenotype. In contrast to the effect of extragenic
ropy
suppressors of
cot-1
, environmental stress-related suppression of
cot-1
did not change COT1 polypeptide expression patterns in the mutant. We suggest that COT1 function is linked to environmental stress response signaling and that altering PKA activity bypasses the requirement for fully functional COT1.
Protein Kinase Involved in Flagellar-Length Control
Authors: Wiese Martin , Kuhn Daniela , Grünfelder Christoph G. 
Published: August 2003

ABSTRACT

During its life cycle, the parasitic protozoon
Leishmania mexicana
differentiates from a flagellated form, the promastigote, to an amastigote form carrying a rudimentary flagellum. Besides biochemical changes, this process involves a change in overall cell morphology including flagellar shortening. A mitogen-activated protein kinase kinase homologue designated LmxMKK was identified in a homology screening and found to be critically involved in the regulation of flagellar assembly and cell size. LmxMKK is exclusively expressed in the promastigote stage and is likely to be regulated by posttranslational mechanisms such as phosphorylation. A deletion mutant for the single-copy gene revealed motile flagella dramatically reduced in length and lacking the paraflagellar rod, a structure adjacent to the axoneme in kinetoplastid flagella. Moreover, a fraction of the cells showed perturbance of the axonemal structure. Complementation of the deletion mutant with the wild-type gene restored typical promastigote morphology. We propose that LmxMKK influences anterograde intraflagellar transport to maintain flagellar length in
Leishmania
promastigotes; as such, it is the first protein kinase known to be involved in organellar assembly.
Formation of Hirano Bodies Induced by Expression of an Actin Cross-Linking Protein with a Gain-of-Function Mutation
Authors: Maselli Andrew , Furukawa Ruth , Thomson Susanne A. M. , Davis Richard C. , Fechheimer Marcus 
Published: August 2003

ABSTRACT

Hirano bodies are paracrystalline actin filament-containing structures reported to be associated with a variety of neurodegenerative diseases. However, the biological function of Hirano bodies remains poorly understood, since nearly all prior studies of these structures were done with postmortem samples of tissue. In the present study, we generated a full-length form of a
Dictyostelium
34-kDa actin cross-linking protein with point mutations in the first putative EF hand, termed 34-kDa ΔEF1. The 34-kDa ΔEF1 protein binds calcium normally but has activated actin binding that is unregulated by calcium. The expression of the 34-kDa ΔEF1 protein in
Dictyostelium
induces the formation of Hirano bodies, as assessed by both fluorescence microscopy and transmission electron microscopy.
Dictyostelium
cells bearing Hirano bodies grow normally, indicating that Hirano bodies are not associated with cell death and are not deleterious to cell growth. Moreover, the expression of the 34-kDa ΔEF1 protein rescues the phenotypes of cells lacking the 34-kDa protein and cells lacking both the 34-kDa protein and α-actinin. Finally, the expression of the 34-kDa ΔEF1 protein also initiates the formation of Hirano bodies in cultured mouse fibroblasts. These results show that the failure to regulate the activity and/or affinity of an actin cross-linking protein can provide a signal for the formation of Hirano bodies. More generally, the formation of Hirano bodies is a cellular response to or a consequence of aberrant function of the actin cytoskeleton.
Specific Protein Targeting during Cell Differentiation: Polarized Localization of Fus1p during Mating Depends on Chs5p in
Saccharomyces cerevisiae
Authors: Santos Beatriz , Snyder Michael 
Published: August 2003

ABSTRACT

In budding yeast,
chs5
mutants are defective in chitin synthesis and cell fusion during mating. Chs5p is a late-Golgi protein required for the polarized transport of the chitin synthase Chs3p to the membrane. Here we show that Chs5p is also essential for the polarized targeting of Fus1p, but not of other cell fusion proteins, to the membrane during mating.
Infimaximal Frames: A Technique for Making Lines Look Like Segments
Authors: Mehlhorn Kurt , Seel Michael 
Published: August 2003

Many geometric algorithms that are usually formulated for points and segments generalize easily to inputs also containing rays and lines. The sweep algorithm for segment intersection is a prototypical example. Implementations of such algorithms do, in general, not extend easily. For example, segment endpoints cause events in sweep line algorithms, but lines have no endpoints. We describe a general technique, which we call infimaximal frames, for extending implementations to inputs also containing rays and lines. The technique can also be used to extend implementations of planar subdivisions to subdivisions with many unbounded faces. We have used the technique successfully in generalizing a sweep algorithm designed for segments to rays and lines and also in an implementation of planar Nef polyhedra.14,1 Our implementation is based on concepts of generic programming in C++ and the geometric data types provided by the C++ Computational Geometry Algorithms Library (CGAL).
A Theoretical Study of a H–H Pair on the BCC Fe(100) Surface
Authors: Gonzalez E. , Brizuela G. , Pistonesi C. , Juan A. 
Published: August 2003

Hydrogen adsorption on Fe(100) was analyzed using a semiempirical theoretical method. Calculations were performed using a Fe 130 cluster. Adsorption sites for one and two hydrogen atoms on the surface correspond to local energy minima configurations. Changes in the electronic structure of surface Fe atoms were analyzed for the system without hydrogen and with one and two adsorbed hydrogen atoms. Fe atoms close to H weaken their metallic bond. This is due to the formation of H–Fe bonds. Hydrogen influences only its nearest neighbor Fe atoms. The H–H interaction was also analyzed and our results show that H–Fe interaction is much stronger than any possible H–H interaction. No additional decohesion is observed in the Fe–Fe bonds; however, more Fe–Fe bonds are affected.
Epstein-Barr Virus (EBV) LMP2A induces alterations in gene transcription similar to those observed in Reed-Sternberg cells of Hodgkin lymphoma
Authors: Portis Toni , Dyck Patricia , Longnecker Richard 
Published: August 2003

AbstractEpstein-Barr virus (EBV) is associated with the development of a variety of malignancies, including Hodgkin lymphoma. One of the few viral transcripts expressed in EBV-positive Hodgkin/Reed-Sternberg (HRS) cells of Hodgkin lymphoma is latent membrane protein 2A (LMP2A). This viral protein blocks B-cell receptor (BCR)-signaling in vitro. Furthermore, expression of LMP2A in developing B cells in vivo induces a global down-regulation of genes necessary for proper B-cell development. In this study we have analyzed gene transcription in primary B cells from LMP2A transgenic mice, LMP2A-expressing human B-cell lines, and LMP2A-positive and -negative EBV-infected lymphoblastoid cell lines (LCLs). We demonstrate that LMP2A increases the expression of genes associated with cell cycle induction and inhibition of apoptosis, alters the expression of genes involved in DNA and RNA metabolism, and decreases the expression of B-cell-specific factors and genes associated with immunity. Furthermore, many alterations in gene expression induced by LMP2A are similar to those recently described in HRS cells of Hodgkin lymphoma and activated, proliferating germinal center centroblasts/centrocytes. These correlations suggest that LMP2A expression in EBV-infected B cells may lead to the induction and maintenance of an activated, proliferative state that could ultimately result in the development of Hodgkin lymphoma. (Blood. 2003;102: 4166-4178)
Notch signaling is necessary but not sufficient for differentiation of dendritic cells
Authors: Cheng Pingyan , Nefedova Yulia , Miele Lucio , Osborne Barbara A. , Gabrilovich Dmitry 
Published: August 2003

AbstractThe Notch family of receptors plays an important role in regulation of cell differentiation via direct contact between hematopoietic progenitor cells (HPCs) and bone marrow stroma (BMS). However the precise contribution of Notch in dendritic cell (DC) differentiation is controversial. In 2 different experimental systems using Notch-1–null embryonic stem cells and Notch-1–deficient HPCs we have found that Notch-1 is necessary for DC differentiation. However, activation of Notch-1 and Notch-2 with cell-bound Notch ligand did not result in differentiation of mature DCs or macrophages. Instead, it caused accumulation of immature myeloid cells. Removal of feeder cells resulted in rapid differentiation of DCs and macrophages. Addition of interleukin 4 (IL-4) into the culture dramatically increased accumulation of functionally potent DCs. Lipopolysaccharide was not able to reproduce this effect. Thus, these data indicate that Notch signaling prevents differentiation of mature myeloid cells. Instead, it results in accumulation of precursors readily able to differentiate into mature DCs once the Notch signal is stopped (eg, after cell emigration from bone marrow) and in the presence of other additional differentiation signals provided by IL-4. Thus, Notch is required but not sufficient for DC differentiation.
Cloning of the t(1;5)(q23;q33) in a myeloproliferative disorder associated with eosinophilia: involvement of PDGFRB and response to imatinib
Authors: Wilkinson Kathryn , Velloso Elvira R. P. , Lopes Luiz Fernando , Lee Charles , Aster Jon C. , Shipp Margaret A. , Aguiar Ricardo C. T. 
Published: August 2003

Abstract
Eosinophilia is common in myeloproliferative disorders (MPDs) with abnormalities of chromosome band 5q31-33, including those that present with t(1;5)(q23;q33). With the development of rational drug therapy, characterization of the molecular targets for these translocations could guide treatment and affect patient survival. We cloned the t(1;5)(q23;q33) and showed that it fuses platelet-derived growth factor receptor beta (PDGFRB) to the coiled-coil domains of a novel partner protein, myomegalin. Using two-color interphase fluorescence in situ hybridization (FISH), we also demonstrated that the eosinophils are clonal in these disorders. Imatinib mesylate has recently been shown to be efficacious in MPDs with PDGFR activation. Therefore, following our molecular studies, we were able to redirect this patient's treatment. Although she had refractory and progressive disease, once imatinib was started, complete clinical and hematologic remission, as well as major cytogenetic response, was achieved. Given the therapeutic implications, our findings stress the need to aggressively investigate the molecular basis of these diseases, with emphasis on the PDGFR family. (Blood. 2003;102: 4187-4190)
Mixture distribution analysis of phenotypic markers reflecting HFE gene mutations
Authors: McLaren Christine E. , Li Kuo-Tung , Garner Chad P. , Beutler Ernest , Gordeuk Victor R. 
Published: August 2003

AbstractThe goal of this study was to determine whether statistical modeling of population data for a phenotypic marker could reflect a major locus gene defect. Identifying mutations in the HFE gene makes it possible to assess the association between transferrin saturation (TS) subpopulations and HFE mutations. Data were analyzed from 27 895 white patients who attended a health appraisal clinic and who had TS and common mutations of HFE determined. Mixture distribution modeling of TS was performed, and the proportion of HFE mutations in TS subpopulations was assessed on a probability basis. Three subpopulations of TS were identified, consistent with Hardy-Weinberg conditions for major locus effects. For men, 72% of the subpopulation with the highest mean TS had HFE gene mutations; they were primarily homozygotes or compound heterozygotes. Seventy-three percent of the subpopulation with moderate mean TS also had HFE gene mutations; they were predominantly simple heterozygotes. Sixty-seven percent of the subpopulation with the lowest mean TS were wild-type homozygotes. Similar results were observed for women. These results suggest that statistical modeling of population clinical laboratory test data can reveal the influence of a major locus gene defect and perhaps can be applied to other aspects of body metabolism than iron. (Blood. 2003;102:4563-4566)
α5β1 integrin as a cellular coreceptor for human parvovirus B19: requirement of functional activation of β1 integrin for viral entry
Authors: Weigel-Kelley Kirsten A. , Yoder Mervin C. , Srivastava Arun 
Published: August 2003

AbstractReplication of the pathogenic human parvovirus B19 is restricted to erythroid progenitor cells. Although blood group P antigen has been reported to be the cell surface receptor for parvovirus B19, a number of nonerythroid cells, which express P antigen, are not permissive for parvovirus B19 infection. We have documented that P antigen is necessary for parvovirus B19 binding but not sufficient for virus entry into cells. To test whether parvovirus B19 utilizes a cell surface coreceptor for entry, we used human erythroleukemia cells (K562), which allow parvovirus B19 binding but not entry. We report here that upon treatment with phorbol esters, K562 cells become adherent and permissive for parvovirus B19 entry, which is mediated by α5β1 integrins, but only in their high-affinity conformation. Mature human red blood cells (RBCs), which express high levels of P antigen, but not α5β1 integrins, bind parvovirus B19 but do not allow viral entry. In contrast, primary human erythroid progenitor cells express high levels of both P antigen and α5β1 integrins and allow β1 integrin–mediated entry of parvovirus B19. Thus, in a natural course of infection, RBCs are likely exploited for a highly efficient systemic dissemination of parvovirus B19.
Heparin-induced substrate behavior of antithrombin Cambridge II
Authors: Mushunje Alec , Zhou Aiwu , Carrell Robin W. , Huntington James A. 
Published: August 2003

AbstractCambridge II (A384S) is a highly prevalent antithrombin variant in the British population (1.14 per 1000) and predisposes carriers to a mild but significant increased risk of thrombosis. To determine if the association of Cambridge II with thrombophilia is due to a perturbation of the antithrombin inhibitory mechanism, we expressed and characterized the variant. Antithrombin Cambridge II was found to be normal in its affinity for heparin, its ability to form sodium dodecyl sulfate-stable complexes with factor Xa and thrombin, and its uncatalyzed stoichiometries and rates of inhibition. However, in the presence of full-length heparin there was a 3- and 7-fold increase in stoichiometry of inhibition of factor Xa and thrombin. The stoichiometries were not affected by pentasaccharides, indicating that the inhibitory mechanism of antithrombin Cambridge II is perturbed only in the presence of a bridging glycosaminoglycan. Thus, the vascular localization of antithrombin Cambridge II would render the carrier slightly thrombophilic. The high occurrence of this mutation and its possible propagation from a few founders suggests an evolutionary advantage, perhaps in decreasing postpartum bleeding. (Blood. 2003;102:4028-4034)
Diagnostic ability of hand-held echocardiography in ventilated critically ill patients
Authors: Vignon Philippe , Chastagner Catherine , François Bruno , Martaillé Jean-François , Normand Sandrine , Bonnivard Michel , Gastinne Hervé 
Published: August 2003

Abstract
Study objectives
To compare the diagnostic capability of recently available hand-held echocardiography (HHE) and of conventional transthoracic echocardiography (TTE) used as a gold standard in critically ill patients under mechanical ventilation.

Design
A prospective and descriptive study.

Setting
The general intensive care unit of a teaching hospital.

Patients
All mechanically ventilated patients requiring a TTE study with a full-feature echocardiographic platform (Sonos 5500®; Philips Medical Systems, Andover, MA, USA) also underwent an echocardiographic examination using a small battery-operated device (33 × 23 cm2, 3.5 kg) (Optigo®; Philips Medical Systems).

Interventions
Each examination was performed independently by two intensivists experienced in echocardiography and was interpreted online. For each patient, the TTE videotape was reviewed by a cardiologist experienced in echocardiography and the final interpretation was used as a reference diagnosis.

Results
During the study period, 106 TTE procedures were performed in 103 consecutive patients (age, 59 ± 18 years; Simplified Acute Physiology Score, 46 ± 14; body mass index, 26 ± 9 kg/m2; positive end-expiratory pressure, 8 ± 4 cmH2O). The number of acoustic windows was comparable using HHE and TTE (233/318 versus 238/318, P = 0.72). HHE had a lower overall diagnostic capacity than TTE (199/251 versus 223/251 clinical questions solved, P = 0.005), mainly due to its lack of spectral Doppler capability. In contrast, diagnostic capacity based on two-dimensional imaging was comparable for both approaches (129/155 versus 135/155 clinical questions solved, P = 0.4). In addition, HHE and TTE had a similar therapeutic impact in 45 and 47 patients, respectively (44% versus 46%, P = 0.9).

Conclusions
HHE appears to have a narrower diagnostic field when compared with conventional TTE, but promises to accurately identify diagnoses based on two-dimensional imaging in ventilated critically ill patients.
Involved-Field Radiotherapy Is Equally Effective and Less Toxic Compared With Extended-Field Radiotherapy After Four Cycles of Chemotherapy in Patients With Early-Stage Unfavorable Hodgkin’s Lymphoma: Results of the HD8 Trial of the German Hodgkin’s Lymphoma Study Group
Authors: Engert Andreas , Schiller Petra , Josting Andreas , Herrmann Richard , Koch Peter , Sieber Markus , Boissevain Friederike , de Wit Maike , Mezger Jörg , Dühmke Eckhart , Willich Normann , Müller Rolf-Peter , Schmidt Bernhard F. , Renner Helmut , Müller-Hermelink Hans Konrad , Pfistner Beate , Wolf Jürgen , Hasenclever Dirk , Löffler Markus , Diehl Volker 
Published: August 2003

Purpose: To investigate whether radiotherapy can be reduced without loss of efficacy from extended field (EF) to involved field (IF) after four cycles of chemotherapy. Patients and Methods: Between 1993 and 1998, patients with newly diagnosed early-stage unfavorable HD were enrolled onto this multicenter study. Patients were randomly assigned to receive cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) + doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) for two cycles followed by radiotherapy of 30 Gy EF + 10 Gy to bulky disease (arm A) or 30 Gy IF + 10 Gy to bulky disease (arm B). Results: Of 1,204 patients randomly assigned to treatment, 1,064 patients were informative and eligible for the arm comparison (532 patients in arm A; 532 patients in arm B). The median observation time was 54 months. Five years after random assignment, the overall survival (OSran) for all eligible patients was 91% and freedom from treatment failure (FFTFran) was 83%. Survival rates at 5 years after start of radiotherapy revealed no differences for arms A and B, respectively, in terms of FFTF (85.8% and 84.2%) and OS at 5 years (90.8% and 92.4%). There also were no differences between arms A and B, respectively, in terms of complete remission (98.5% and 97.2%), progressive disease (0.8% and 1.9%), relapse (6.4% and 7.7%), death (8.1% and 6.4%), and secondary neoplasia (4.5% and 2.8%). In contrast, acute side effects including leukopenia, thrombocytopenia, nausea, gastrointestinal toxicity, and pharyngeal toxicity were more frequent in the EF arm. Conclusion: Radiotherapy volume size reduction from EF to IF after COPP + ABVD chemotherapy for two cycles produces similar results and less toxicity in patients with early-stage unfavorable HD.