bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of tubulin synthesis and cell cycle progression in mammalian cells by γ‐tubulin‐mediated microtubule nucleation
Authors: Zhou Jun , Shu Hong‐Bing , Joshi Harish C. 
Published: October 2004

AbstractWe have previously shown that γ‐tubulin, the third member of the tubulin family that functions in microtubule nucleation, when overexpressed, accumulates throughout the cytoplasm and forms numerous ectopic microtubule nucleation sites in mammalian cells (Shu and Joshi [1995] J. Cell. Biol. 130:1137–1147). We now show that overexpression of γ‐tubulin differentially upregulates the synthesis of α‐ and β‐tubulins in mammalian cells. Surprisingly, despite a dramatic increase in the level of γ‐tubulin protein in transfected cells, there is no obvious alteration in the level of endogenous γ‐tubulin mRNA, suggesting that synthesis of γ‐tubulin might employ a regulatory mechanism other than the autoregulatory pathway shared by α‐ and β‐tubulins. Interestingly, a significant number of mammalian cells transfected with γ‐tubulin fail to form normal bipolar mitotic spindle during mitosis; instead, numerous microtubules occur in the cytoplasm intermingled with the condensed chromosomes. In addition, they reduplicate their DNA after an abnormal mitotic exit. These results thus suggest that the number of microtubule nucleation sites, or even γ‐tubulin itself, might play an important role in the regulation of tubulin synthesis as well as cell cycle progression. J. Cell. Biochem. 84: 472–483, 2002. © 2001 Wiley‐Liss, Inc.
Multiple collagen I gene regulatory elements have sites of stress‐induced DNA duplex destabilization and nuclear scaffold/matrix association potential
Authors: Mielke Christian , Christensen Morten O. , Westergaard Ole , Bode Jürgen , Benham Craig J. , Breindl Michael 
Published: October 2004

AbstractThe availability of the complete nucleotide sequences of numerous prokaryotic and eukaryotic organisms should stimulate the development and application of computer‐based approaches for studying genome organization and function. Earlier work has shown that distinct regulatory DNA elements can be identified by computational analysis as sites of stress‐induced DNA duplex destabilization (SIDD). Here we report the results of computational and experimental analyses of previously identified regulatory elements in the murine α1(I) collagen (Col1a1) gene domain. We found that several distal 5′ DNase I‐hypersensitive sites (HSs) which function in the chromatin loop organization of the Col1a1 gene are characterized by strongly destabilized SIDD profiles. Elements in the proximal 5′ promoter and first intron which differentially regulate Col1a1 promoter activity in different collagen‐producing cell types also contain SIDD sites. All 5′ elements associated with destabilized sites are shown to have nuclear matrix binding activity in an in vitro binding assay. Other putative regulatory elements in the transcribed and 3′‐flanking regions of the Col1a1 gene, including both of its polyadenylation sites, are also associated with SIDD peaks. The human COL1A1 gene has periodic SIDD peaks within the transcribed region, suggesting that abundantly expressed genes may require SIDDs acting as topological sinks during transcription. The 5′ ends of the murine Col1a1 and the homologous human gene revealed similar SIDD profiles, but limited DNA sequence similarity, indicating that some DNA functions are evolutionarily conserved by preserving higher order DNA structural properties rather than nucleotide sequence. Our results show that destabilized SIDD profiles are a common feature of eukaryotic regulatory DNA elements with such diverse functions as chromatin organization, cell‐specific transcriptional enhancement, and initiation and termination of transcription. They demonstrate the usefulness of computational analyses that predict SIDD properties in reliably identifying DNA elements involved in the structural organization of the eukaryotic genome and the regulation of its expression. J. Cell. Biochem. 84: 484–496, 2002. © 2001 Wiley‐Liss, Inc.
Upregulation of mitochondrial peripheral benzodiazepine receptor expression by cytokine‐induced damage of human pancreatic islets
Authors: Trincavelli M. Letizia , Marselli Lorella , Falleni Alessandra , Gremigni Vittorio , Ragge Esther , Dotta Francesco , Santangelo Carmela , Marchetti Piero , Lucacchini Antonio , Martini Claudia 
Published: October 2004

AbstractCytokines produced by immune system cells infiltrating pancreatic islets are candidate mediators of islet beta‐cell destruction in autoimmune insulin‐dependent diabetes mellitus. After 72 h exposure of human pancreatic islets to a cytotoxic cytokine combination of interleukin 1 beta (50 U/ml), tumor necrosis factor alpha (1,000 U/ml), and interferon gamma (1,000 U/ml), an increase of cell death vs. control islets was demonstrated by TUNEL and cell death detection ELISA method. Islet death was associated with apoptosis and mitochondrial swelling as evidenced by electron microscopy. This effect was correlated with a marked decrease of Bcl‐2 mRNA expression (without any major change of Bax mRNA) and a marked increase of inducible nitric oxide synthase mRNA. Since peripheral benzodiazepine receptors constitute the aspecific mitochondrial permeability transition pore, and that it has been suggested to be involved in cytokine‐induced cell death, we evaluated the effects of the cytotoxic cytokines on PBR density and mRNA expression. We demonstrated that cytokine treatment of human islets induced an increase of maximum density of 3H1‐(2‐chlorophenyl‐N‐methyl‐1‐methylpropyl)‐3‐ isoquinolinecarboxamide binding sites, (5,110 ± 193 vs. 3,421 ± 336 fmol/mg proteins, P < 0.05) with no significant change in the affinity constant value (9.45 ± 0.869 vs. 8.7 ± 1.159 nM). Moreover, an increase of the expression of peripheral benzodiazepine receptor mRNA was observed, suggesting an increased transcription from the coding gene. These results suggest a possible role of peripheral benzodiazepine receptors in the organism response to tissue damage associated with inflammatory mediator production. J. Cell. Biochem. 84: 636–644, 2002. © 2001 Wiley‐Liss, Inc.
Interaction of the heart‐specific LIM domain protein, FHL2, with DNA‐binding nuclear protein, hNP220
Authors: Ng Enders Kai On , Chan Kwok Keung , Wong Chi Hang , Tsui Stephen Kwok Wing , Ngai Sai Ming , Lee Simon Ming Yuen , Kotaka Masayo , Lee Cheuk Yu , Waye Mary Miu Yee , Fung Kwok Pui 
Published: October 2004

AbstractUsing a yeast two‐hybrid library screen, we have identified that the heart specific FHL2 protein, four‐and‐a‐half LIM protein 2, interacted with human DNA‐binding nuclear protein, hNP220. Domain studies by the yeast two‐hybrid interaction assay revealed that the second LIM domain together with the third and the fourth LIM domains of FHL2 were responsible to the binding with hNP220. Using green fluorescent protein (GFP)‐FHL2 and blue fluorescent protein (BFP)‐hNP220 fusion proteins co‐expressed in the same cell, we demonstrated a direct interaction between FHL2 and hNP220 in individual nucleus by two‐fusion Fluorescence Resonance Energy Transfer (FRET) assay. Besides, Western blot analysis using affinity‐purified anti‐FHL2 antipeptide antibodies confirmed a 32‐kDa protein of FHL2 in heart only. Virtually no expression of FHL2 protein was detected in brain, liver, lung, kidney, testis, skeletal muscle, and spleen. Moreover, the expression of FHL2 protein was also detectable in the human diseased heart tissues. Our results imply that FHL2 protein can shuttle between cytoplasm and nucleus and may act as a molecular adapter to form a multicomplex with hNP220 in the nucleus, thus we speculate that FHL2 may be particularly important for heart muscle differentiation and the maintenance of the heart phenotype. J. Cell. Biochem. 84: 556–566, 2002. © 2001 Wiley‐Liss, Inc.
Evidence for the involvement of cathepsin B in skeletal myoblast differentiation
Authors: Jane Derek T. , DaSilva Luis , Koblinski Jennifer , Horwitz Marshall , Sloane Bonnie F. , Dufresne Michael J. 
Published: October 2004

AbstractOur previous studies suggest that the cysteine protease cathepsin B (catB) is involved in skeletal myoblast differentiation (myogenesis). To test this hypothesis, we examined the effect of trapping one of the two catB alleles on the ability of C2C12 cells to differentiate. During differentiation, catB gene‐trapped C2C12 mouse myoblasts (RT‐27) demonstrated a similar pattern of intracellular catB activity and protein expression compared to that observed in control C2C12 myoblasts and myoblasts trapped in a gene other than catB. However, compared to control myoblast cell lines, levels of catB activity and protein at each stage of RT‐27 differentiation were reduced. The reductions in levels of catB were associated with reductions in several myogenic phenotypes including reduced levels of creatine phosphokinase activity and myosin heavy chain protein, two late biochemical markers of myogenesis, and reduced myotube size and extent of myotube formation over time. Comparable reductions were not observed for myogenin protein, an early biochemical marker of myogenesis, or in myokinase activity and catB related cathepsin L‐type activity, two non‐specific proteins. Finally, both control and catB gene‐trapped myoblasts secreted active catB at pH 7.0. However levels of active pericellular/secreted catB were 50% lower in catB gene‐trapped myoblasts. Collectively, these results support a functional link between catB expression and skeletal myogenesis and suggest a role for active pericellular/secreted catB in myoblast fusion. J. Cell. Biochem. 84: 520–531, 2002. © 2001 Wiley‐Liss, Inc.
Identification and mapping of nuclear matrix‐attachment regions in a one megabase locus of human chromosome 19q13.12: Long‐range correlation of S/MARs and gene positions
Authors: Chernov I.P. , Akopov S.B. , Nikolaev L.G. , Sverdlov E.D. 
Published: October 2004

AbstractThe first draft human genome sequence now available allowed the identification of an enormous number of gene coding areas of the genomic DNA. However, a great number of regulatory elements such as enhancers, promoters, transcription terminators, or replication origins can not be identified unequivocally by their nucleotide sequences in complex eukaryotic genomes. One important subclass of these type of sequences is scaffold/matrix attachment regions (S/MARs) that were hypothesized to anchor chromatin loops or domains to the nuclear matrix and/or chromosome scaffold. We developed an experimental selection procedure to identify S/MARs within a completely sequenced one megabase (1 Mb) long gene‐richD19S208‐COX7A1locus of human chromosome 19. A library of S/MAR elements from the locus was prepared and shown to contain ∼20 independent S/MARs. Sixteen of them were isolated, sequenced, and assigned to certain positions within the locus. A majority of the S/MARs identified (11 out of 16) lie in intergenic regions, suggesting their structural role, i.e., delimitation of chromatin domains. These 11 S/MARs subdivide the locus into 10 domains ranging from 6 to 272 kb with an average domain size of 88 kb. The remaining five S/MARs were found within intronic sequences ofAPLP1,HSPOX1,MAG, andNPHS1genes, and can be tentatively characterized as regulatory S/MARs. The correspondence of the chromatin domains defined by the S/MARs to functional characteristics of the genes therein is discussed. The approach described can be a prototype of a similar search of long sequenced genomic stretches and/or whole chromosomes for various regulatory elements. J. Cell. Biochem. 84: 590–600, 2002. © 2001 Wiley‐Liss, Inc.
Necdin interacts with the ribonucleoprotein hnRNP U in the nuclear matrix
Authors: Taniura Hideo , Yoshikawa Kazuaki 
Published: October 2004

AbstractNecdin is expressed predominantly in terminally differentiated neurons, and its ectopic expression suppresses cell proliferation. We screened a cDNA library from neurally differentiated embryonal carcinoma P19 cells for necdin‐binding proteins by the yeast two‐hybrid assay. One of the positive clones contained cDNA encoding a carboxyl‐terminal portion of heterogeneous nuclear ribonucleoprotein U (hnRNP U), a nuclear matrix‐associated protein that interacts with chromosomal DNA. We isolated cDNA encoding full‐length mouse hnRNP U to analyze its physical and functional interactions with necdin. The necdin‐binding site of hnRNP U was located near a carboxyl‐terminal region that mediated the association between hnRNP U and the nuclear matrix. In postmitotic neurons, endogenously expressed necdin and hnRNP U were detected in the nuclear matrix and formed a stable complex. Ectopically expressed necdin was concentrated in the nucleoli, but coexpressed hnRNP U recruited necdin to the nucleoplasmic compartment of the nuclear matrix. Furthermore, under the same conditions necdin and hnRNP U cooperatively suppressed the colony formation of transfected SAOS‐2 cells. These results suggest that necdin suppresses cell proliferation through its interaction with hnRNP U in the specific subnuclear structure. J. Cell. Biochem. 84: 545–555, 2002. © 2001 Wiley‐Liss, Inc.
Sodium arsenite suppresses human papillomavirus‐16 E6 gene and enhances apoptosis in E6‐transfected human lymphoblastoid cells
Authors: Chou Ruey‐Hwang , Huang Haimei 
Published: October 2004

AbstractThe p53 tumor suppressor pathway is disrupted by human papillomavirus (HPV) in most cervical cancer cells. The E6 proteins, which could mediate p53 degradation, are related to cellular immortalization, transformation, and tumor formation. In order to study the E6 abrogated p53 function in stress, we transfected HPV‐16 E6 gene to TK6 cells in this study. Here we showed that HPV‐16 E6 mRNA levels decreased in a dose dependent manner after sodium arsenite (SA) treatment, but not after X‐irradiation. P53, p21, and MDM2 were induced in E6‐transfected TK6 cells, as well as in parental TK6 cells after arsenite treatment. But the above proteins were only induced in TK6 cells after X‐irradiation. It indicated that arsenite, but not X‐ray, could suppress the transcription of E6 gene and therefore activate the p53 tumor suppressor pathway in TK6‐E6 cells. After arsenite treatment, TK6‐E6 cells showed more sub‐G1 apoptosis, activated caspase‐3/CPP32 fragment, DNA ladder, and less viability than parental TK6 cells, indicating that arsenite enhanced apoptosis in E6‐transfected TK6 cells. In contrast, after X‐irradiation, TK6‐E6 cells showed less sub‐G1 apoptosis and higher viability than parental TK6 cells. Thus, it would be another possible strategy to promote arsenite as another potential candidate for the therapeutic purpose in HPV‐positive cancer cells. J. Cell. Biochem. 84: 615–624, 2002. © 2001 Wiley‐Liss, Inc.
Antisense Egr‐1 RNA driven by the CMV promoter is an inhibitor of vascular smooth muscle cell proliferation and regrowth after injury
Authors: Fahmy Roger G. , Khachigian Levon M. 
Published: October 2004

AbstractSmooth muscle cell (SMC) migration and proliferation are key events in the pathogenesis of atherosclerotic and post‐angioplasty restenotic lesions. Mechanical injury to the artery wall induces the SMC expression of the zinc finger transcription factor, early growth response factor‐1 (Egr‐1). Egr‐1 in turn can bind and activate the promoters of many genes, whose products influence vascular repair. Here, a 127‐bp cDNA fragment corresponding to the 5′ region of murine Egr‐1 mRNA was cloned into a CMV‐driven expression vector, in the sense or antisense orientation. We demonstrate that antisense Egr‐1 RNA inhibited rat vascular SMC proliferation, whereas the sense counterpart produced only a modest effect. By semi‐quantitative reverse‐transcription PCR, antisense Egr‐1 RNA blocked serum‐inducible Egr‐1 mRNA expression. Western blot analysis demonstrated that antisense RNA overexpression inhibited Egr‐1 protein synthesis, without affecting levels of the immediate early gene product, c‐fos. Finally, antisense Egr‐1 RNA overexpression inhibited SMC regrowth after mechanical injury in vitro. In contrast, sense Egr‐1 RNA had no effect on SMC repair, Egr‐1 mRNA expression or protein synthesis. Analysis of transfection efficiencies revealed that both CMV‐driven constructs (sense and antisense) were taken up by the SMCs with equivalent efficiency. These findings provide the first demonstration of antisense RNA strategies targeting Egr‐1 as inhibitors of Egr‐1 and Egr‐1‐dependent cellular processes. The antisense RNA approach may be potentially useful in gene therapeutic efforts to control SMC growth in the injured artery wall. J. Cell. Biochem. 84: 575–582, 2002. © 2001 Wiley‐Liss, Inc.
Detection of SV40 DNA sequences in malignant mesothelioma specimens from the United States, but not from Turkey
Authors: De Rienzo Assunta , Tor Meltem , Sterman Daniel H. , Aksoy Ferda , Albelda Steven M. , Testa Joseph R. 
Published: October 2004

AbstractThe incidence of malignant mesothelioma (MM) shows a strong epidemiological association with exposure to asbestos fibers. Recently, simian virus 40 (SV40) DNA sequences have been reported in MM tumor specimens from the United States and several European countries, and the SV40 tumor virus has been implicated as a potential co‐factor in the etiology of this disease. However, several large studies from the US, Finland, and Turkey did not detect SV40 sequences in MM samples. To address this discrepancy, MM specimens from Turkey and the US were analyzed in the same laboratory under identical conditions to detect the presence of SV40 DNA. We detected SV40 sequences in 4 of 11 specimens from the United States, but in none of the 9 Turkish samples examined. These findings suggest that geographical differences exist with regard to the involvement of SV40 in human tumors. J. Cell. Biochem. 84: 455–459, 2002. © 2001 Wiley‐Liss, Inc.
Characterization of interferon gamma receptors on osteoclasts: Effect of interferon gamma on osteoclastic superoxide generation
Authors: Yang Su , Madyastha Prema , Ries William , Key Lyndon L. 
Published: October 2004

AbstractOsteoclasts are the primary cells responsible for bone resorption. Osteoclast formation and bone resorption activities involve processes tightly controlled by a network of cytokines. The presence of interferon gamma (IFN‐γ) receptors on osteoclasts is a necessary prerequisite for IFN‐γ to directly affect osteoclastic activity. To date, the presence of the IFN‐γ receptor on osteoclasts has not been established. This study provides evidence that osteoclasts express the IFN‐γ receptor. Specific binding of IFN‐γ to the osteoclastic receptor stimulates osteoclastic superoxide generation. The p91 and p47 components of the NADPH oxidase increase after IFN‐γ stimulation and may account for the enhanced superoxide generation. Antisense experiments targeting p91 and p47 subunits abrogate the increased osteoclastic superoxide production stimulated by IFN‐γ. Thus, superoxide generation by osteoclasts is stimulated by activation of a functional IFN‐γ receptor on the osteoclast. J. Cell. Biochem. 84: 645–654, 2002. © 2001 Wiley‐Liss, Inc.
Phosphorylation of tyrosine 256 facilitates nuclear import of atypical protein kinase C
Authors: White Wendy O. , Seibenhener M. Lamar , Wooten Marie W. 
Published: October 2004

AbstractHerein, we employed a combined approach of molecular modeling and site‐directed mutagenesis to address the role of tyrosine phosphorylation in transport of atypical protein kinase C (aPKC) into the nucleus. Computer modeling of the three‐dimensional structure of the aPKC catalytic core, reveals that tyrosine 256 (Tyr256) is located at the lip of the activation loop and is conserved among members of the aPKC family, ι/λ and ζ. Based on these findings, we examined whether tyrosine phosphorylation of aPKC on the activation lip may facilitate nuclear import. An antiserum was generated that selectively recognizes the phosphorylated Tyr256 residue in aPKC. By isolating nuclei of PC12 cells and immunoprecipitating aPKC with Ab‐PY256, we observed that Tyr256 is rapidly phosphorylated upon NGF treatment prior to entry of aPKC into the nucleus. aPKC was observed to exclusively bind to importin‐β. The interaction between importin‐β and aPKC was enhanced upon tyrosine phosphorylation of aPKC and binding was abrogated when Tyr256 was mutated to phenylalanine. We propose that phosphorylation of aPKC at Tyr256 induces a conformation, whereby, the arginine‐rich NLS is exposed, which then binds importin‐β leading to import of aPKC into the nucleus. Altogether, these findings document a novel role for the tyrosine phosphorylation in regulating import of atypical PKC into the nucleus. J. Cell. Biochem. 85: 42–53, 2002. © 2002 Wiley‐Liss, Inc.
Hormonal regulation of the c‐fms proto‐oncogene in breast cancer cells is mediated by a composite glucocorticoid response element
Authors: Flick Maryann B. , Sapi Eva , Kacinski Barry M. 
Published: October 2004

AbstractWe have previously reported that glucocorticoids markedly increase and anti‐glucocorticoids (such as RU‐486) block c‐fms RNA and protein expression in some breast cancer cell lines, but not in others, and that this increase is the consequence of increased transcription from the first, epithelial cell‐specific promoter of the c‐fms gene (encoding CSF‐1R, macrophage colony‐stimulating factor receptor). Employing DNaseI protection and electrophoretic mobility shift assays (EMSA), we now demonstrate that DNA‐transcription factor protein complexes are formed on the c‐fms first promoter at a composite regulatory element containing overlapping binding sites for AP‐1 proteins, bHLH factors, and the glucocorticoid receptor (GR). Competition studies indicate that transcription factor proteins bind the AP‐1 site and the GR element (GRE) and both GR and AP‐1 proteins are involved in DNA–protein complex formation. The complexes differ in quantity and glucocorticoid inducibility in the different breast cancer cell lines studied depending on whether the promoter responds to glucocorticoid stimulation. Transient transfection of promoter/reporter gene constructs resulted in reduced basal transcription activity of this promoter and lack of glucocorticoid stimulation when the AP‐1 site was mutated. We conclude that AP‐1 proteins, GR and associated co‐factors regulate transcription from the c‐fms first promoter and that differences in recruitment of the various components are responsible for cell specific repression and activation of this gene in breast carcinoma cell lines. J. Cell. Biochem. 85: 10–23, 2002. © 2002 Wiley‐Liss, Inc.