bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of CD2 locus control region sequences on gene expression by retroviral and lentiviral vectors
Authors: Indraccolo Stefano , Minuzzo Sonia , Roccaforte Francesca , Zamarchi Rita , Habeler Walter , Stievano Laura , Tosello Valeria , Klein Dieter , Günzburg Walter H. , Basso Giuseppe , Chieco-Bianchi Luigi , Amadori Alberto 
Published: October 2002

Abstract
Locus control region (LCR) sequences are involved in the establishment of open chromosomal domains. To evaluate the possibility of exploiting the human CD2 LCR to regulate gene expression by Moloney murine leukemia virus (Mo-MLV)–based retroviral vectors in T cells, it was included in vectors carrying the enhanced green fluorescence protein (EGFP) reporter gene; then transduction in vitro of lymphoid and nonlymphoid cell lines was performed. Deletion of the viral enhancer in the Mo-MLV long terminal repeat was necessary to detect LCR activity in the context of these retroviral vectors. It was found that a full-length (2.1 kb), but not a truncated (1.0 kb), CD2 LCR retained the ability to modulate reporter gene expression by Mo-MLV–derived retroviral vectors, leading to a homogeneous, unimodal pattern of EGFP expression that remained unmodified in culture over time, specifically in T-cell lines; on the other hand, viral titer was strongly reduced compared with vectors not carrying the LCR. Lentiviral vectors containing the CD2 LCR could be generated at higher titers and were used to analyze its effects on gene expression in primary T cells. Subcutaneous implantation of genetically modified cells in immunodeficient mice showed that retroviral vectors carrying the CD2 LCR conferred an advantage in terms of transgene expression in vivo, compared with the parental vector, by preventing the down-modulation of EGFP expression. These findings suggest a potential application of this LCR to increase gene expression by retroviral and lentiviral vectors in T lymphocytes.
Expression and function of CD105 during the onset of hematopoiesis from Flk1+ precursors
Authors: Cho Sarah K. , Bourdeau Annie , Letarte Michelle , Zúñiga-Pflücker Juan Carlos 
Published: October 2002

AbstractDuring ontogeny, the hematopoietic system is established from mesoderm-derived precursors; however, molecular events regulating the onset of hematopoiesis are not well characterized. Several members of the transforming growth factor β (TGF-β) superfamily have been implicated as playing a role during mesoderm specification and hematopoiesis. CD105 (endoglin) is an accessory receptor for members of the TGF-β superfamily. Here it is reported that during the differentiation of murine embryonic stem (ES) cells in vitro, hematopoietic commitment within Flk1+ mesodermal precursor populations is characterized by CD105 expression. In particular, CD105 is expressed during the progression from the Flk1+CD45− to Flk1−CD45+ stage. The developmentally regulated expression of CD105 suggests that it may play a role during early hematopoiesis from Flk1+ precursors. To determine whether CD105 plays a functional role during early hematopoietic development, the potential of CD105-deficient ES cells to differentiate into various hematopoietic lineages in vitro was assessed. In the absence of CD105, myelopoiesis and definitive erythropoiesis were severely impaired. In contrast, lymphopoiesis appeared to be only mildly affected. Thus, these findings suggest that the regulated expression of CD105 functions to support lineage-specific hematopoietic development from Flk1+ precursors.
Transforming growth factor β1 mediates cell-cycle arrest of primitive hematopoietic cells independent of p21Cip1/Waf1or p27Kip1
Authors: Cheng Tao , Shen Hongmei , Rodrigues Neil , Stier Sebastian , Scadden David T. 
Published: October 2002

AbstractThe regulation of stem cell proliferation is a poorly understood process balancing rapid, massive blood cell production in times of stress with maintenance of a multipotent stem cell pool over decades of life. Transforming growth factor β1 (TGF-β1) has pleiotropic effects on hematopoietic cells, including the inhibition of primitive cell proliferation. It was recently demonstrated that the cyclin-dependent kinase inhibitors, p21Cip1/Waf1 (p21) and p27Kip1 (p27), can inhibit the proliferation of hematopoietic stem cells and progenitor cells, respectively. The relation of TGF-β1 stimulation to p21 and p27 was examined using a fine-mapping approach to gene expression in individual cells. Abundant TGF-β1 expression and p21 expression were documented in quiescent, cytokine-resistant hematopoietic stem cells and in terminally differentiated mature blood cells, but not in proliferating progenitor cell populations. TGF-β1 receptor (TβR II) was expressed ubiquitously without apparent modulation. Cell- cycle–synchronized 32D cells exposed to TGF-β1 demonstrated a marked antiproliferative effect of TGF-β1, yet neither the level of p21 mRNA nor the protein level of either p21 or p27 was altered. To corroborate these observations in primary cells, bone marrow mononuclear cells derived from mice engineered to be deficient in p21 or p27 were assessed. Progenitor and primitive cell function was inhibited by TGF-β1 equivalently in −/− and +/+ littermate controls. These data indicate that TGF-β1 exerts its inhibition on cell cycling independent of p21 and p27 in hematopoietic cells. TGF-β1 and p21 or p27 participate in independent pathways of stem cell regulation, suggesting that targeting each may provide complementary strategies for enhancing stem or progenitor cell expansion and gene transduction.
A cytoplasmic serine protein kinase binds and may regulate the Fanconi anemia protein FANCA
Authors: Yagasaki Hiroshi , Adachi Daiki , Oda Tsukasa , Garcia-Higuera Irene , Tetteh Nii , D'Andrea Alan D. , Futaki Makoto , Asano Shigetaka , Yamashita Takayuki 
Published: October 2002

Abstract
Fanconi anemia (FA) is an autosomal recessive disease with congenital anomalies, bone marrow failure, and susceptibility to leukemia. Patient cells show chromosome instability and hypersensitivity to DNA cross-linking agents. At least 8 complementation groups (A-G) have been identified and 6 FAgenes (for subtypes A, C, D2, E, F, and G) have been cloned. Increasing evidence indicates that a protein complex assembly of multiple FA proteins, including FANCA and FANCG, plays a crucial role in the FA pathway. Previously, it was reported that FANCA was phosphorylated in lymphoblasts from normal controls, whereas the phosphorylation was defective in those derived from patients with FA of multiple complementation groups. The present study examined phosphorylation of FANCA ectopically expressed in FANCA− cells. Several patient-derived mutations abrogated in vivo phosphorylation of FANCA in this system, suggesting that FANCA phosphorylation is associated with its function. In vitro phosphorylation studies indicated that a physiologic protein kinase for FANCA (FANCA-PK) forms a complex with the substrate. Furthermore, at least a part of FANCA-PK as well as phosphorylated FANCA were included in the FANCA/FANCG complex. Thus, FANCA-PK appears to be another component of the FA protein complex and may regulate function of FANCA. FANCA-PK was characterized as a cytoplasmic serine kinase sensitive to wortmannin. Identification of the protein kinase is expected to elucidate regulatory mechanisms that control the FA pathway.
Lymphoid apoptosis and myeloid hyperplasia in CCAAT displacement protein mutant mice
Authors: Sinclair Angus M. , Lee Jamie A. , Goldstein Adrian , Xing Dongxia , Liu Shengxi , Ju Ruzeng , Tucker Philip W. , Neufeld Ellis J. , Scheuermann Richard H. 
Published: October 2002

AbstractCCAAT displacement protein (cux/CDP) is an atypical homeodomain protein that represses expression of several developmentally regulated lymphoid and myeloid genes in vitro, including gp91-phox, immunoglobulin heavy chain, the T-cell receptor β and γ chains, and CD8. To determine how this activity affects cell development in vivo, a hypomorphic allele of cux/CDP was created by gene targeting. Homozygous mutant mice (cux/CDPΔHD/ΔHD) demonstrated a partial neonatal lethality phenotype. Surviving animals suffered from a wasting disease, which usually resulted in death between 2 and 3 weeks of age. Analysis of T lymphopoiesis demonstrated that cux/CDPΔHD/ΔHD mice had dramatically reduced thymic cellularity due to enhanced apoptosis, with a preferential loss of CD4+CD8+ thymocytes. Ectopic CD25 expression was also observed in maturing thymocytes. B lymphopoiesis was also perturbed, with a 2- to 3-fold reduction in total bone marrow B-lineage cells and a preferential loss of cells in transition from pro-B/pre-BI to pre-BII stages due to enhanced apoptosis. These lymphoid abnormalities were independent of effects related to antigen receptor rearrangement. In contrast to the lymphoid demise, cux/CDPΔHD/ΔHD mice demonstrated myeloid hyperplasia. Bone marrow reconstitution experiments identified that many of the hematopoietic defects were linked to microenvironmental effects, suggesting that underexpression of survival factors or overexpression of death-inducing factors accounted for the phenotypes observed. Tumor necrosis factor (TNF) levels were elevated in several tissues, especially thymus, suggesting that TNF may be a target gene for cux/CDP-mediated repression. These data suggest that cux/CDP regulates normal hematopoiesis, in part, by modulating the levels of survival and/or apoptosis factors expressed by the microenvironment.
Identification of CD146 as a component of the endothelial junction involved in the control of cell-cell cohesion
Authors: Bardin Nathalie , Anfosso Francine , Massé Jean-Marc , Cramer Elisabeth , Sabatier Florence , Bivic André Le , Sampol José , Dignat-George Françoise 
Published: October 2002

AbstractCD146 is a cell-surface molecule belonging to the immunoglobulin superfamily and expressed in all types of human endothelial cells. Confocal and electron microscopic analysis of confluent human umbilical vein endothelial cells (HUVECs) were used to demonstrate that CD146 is a component of the endothelial junction. Double immunolabeling with vascular endothelial cadherin showed that CD146 is localized outside the adherens junction. Moreover, CD146 expression is not restricted to the junction, since part of the labeling was detectable at the apical side of the HUVECs. Interestingly, cell-surface expression of CD146 increased when HUVECs reached confluence. In addition, the paracellular permeability of CD146-transfected fibroblast cells was decreased compared with that of control cells. Finally, CD146 colocalized with actin, was partly resistant to Triton X-100 extraction, and had its expression altered by actin-disrupting agents, indicating that CD146 is associated with the actin cytoskeleton. These results show the regulated expression of CD146 at areas of cell-cell junction and strongly suggest involvement of CD146 as a mediator of cell-cell interaction.
Congenital afibrinogenemia: mutations leading to premature termination codons in fibrinogen Aα-chain gene are not associated with the decay of the mutant mRNAs
Authors: Asselta Rosanna , Duga Stefano , Spena Silvia , Santagostino Elena , Peyvandi Flora , Piseddu Gavino , Targhetta Roberto , Malcovati Massimo , Mannucci Pier Mannuccio , Tenchini Maria Luisa 
Published: October 2002

AbstractCongenital afibrinogenemia is a rare coagulation disorder with autosomal recessive inheritance, characterized by the complete absence or extremely reduced levels of fibrinogen in patients' plasma and platelets. Eight afibrinogenemic probands, with very low plasma levels of immunoreactive fibrinogen were studied. Sequencing of the fibrinogen gene cluster of each proband disclosed 4 novel point mutations (1914C&gt;G, 1193G&gt;T, 1215delT, and 3075C&gt;T) and 1 already reported (3192C&gt;T). All mutations, localized within the first 4 exons of the Aα-chain gene, were null mutations predicted to produce severely truncated Aα-chains because of the presence of premature termination codons. Since premature termination codons are frequently known to affect the metabolism of the corresponding messenger RNAs (mRNAs), the degree of stability of each mutant mRNA was investigated. Cotransfection experiments with plasmids expressing the wild type and each of the mutant Aα-chains, followed by RNA extraction and semiquantitative reverse-transcriptase–polymerase chain reaction analysis, demonstrated that all the identified null mutations escaped nonsense-mediated mRNA decay. Moreover, ex vivo analysis at the protein level demonstrated that the presence of each mutation was sufficient to abolish fibrinogen secretion.
Structure-function analysis of the antioxidant properties of haptoglobin
Authors: Melamed-Frank Meira , Lache Orit , Enav Benjamin I. , Szafranek Tal , Levy Nina S. , Ricklis Rebecca M. , Levy Andrew P. 
Published: October 2002

AbstractHaptoglobin serves as an antioxidant by virtue of its ability to prevent hemoglobin-driven oxidative tissue damage. It was recently demonstrated that an allelic polymorphism in the haptoglobin gene is predictive of the risk for numerous microvascular and macrovascular diabetic complications. Because these complications are attributed in large part to an increase in oxidative stress, a study was conducted to determine whether the different protein products of the 2 haptoglobin alleles differed in the antioxidant protection they provided. A statistically significant difference was found in the antioxidant capacity of purified haptoglobin protein produced from the 2 different alleles, consistent with the hypothesis that differences in genetically determined antioxidant status may explain differential susceptibility to diabetic vascular complications. These differences may be amplified in the vessel wall because of differences in the sieving capacity of the haptoglobin types. Therefore, an attempt was made to identify the minimal haptoglobin sequences necessary to inhibit oxidation by hemoglobin in vitro, and 2 independent haptoglobin peptides that function in this fashion as efficiently as native haptoglobin were identified. Identification of the biochemical basis for differences among haptoglobin types may lead to the rational development of new pharmacologic agents, such as the mini-haptoglobin described here, to avert the development of diabetic vascular complications.
Heterogeneity of endothelial junctions is reflected by differential expression and specific subcellular localization of the three JAM family members
Authors: Aurrand-Lions Michel , Johnson-Leger Caroline , Wong Cindy , Du Pasquier Louis , Imhof Beat A. 
Published: October 2002

AbstractEndothelial cells are linked to each other through intercellular junctional complexes that regulate the barrier and fence function of the vascular wall. The nature of these intercellular contacts varies with the need for permeability: For example, in brain the impervious blood-brain barrier is maintained by “tight” contacts between endothelial cells. By contrast, in high endothelial venules (HEVs), where lymphocytes continuously exit the bloodstream, the contacts are generally leaky. The precise molecular components that define the type of junction remain to be characterized. An immunoglobulin superfamily molecule named JAM-2, specifically expressed in lymphatic endothelial cells and HEVs, was recently identified. JAM-3 was cloned and characterized in the current study, and JAM-1, -2, and -3 were shown to form a novel protein family belonging to the larger cortical thymocyte Xenopus (CTX) molecular family. Using antibodies specific for each of the 3 family members, their specific participation in different types of cell-cell contact in vivo and their specific and differential localization in lateral contacts or tight junctions were demonstrated. Furthermore, it was shown that JAM-1 and JAM-2 differentially regulate paracellular permeability, suggesting that the presence of JAM-1, -2, or -3 in vascular junctions may play a role in regulating vascular function in vivo.
Rac, a small guanosine triphosphate–binding protein, and p21-activated kinase are activated during platelet spreading on collagen-coated surfaces: roles of integrin α2β1
Authors: Suzuki-Inoue Katsue , Yatomi Yutaka , Asazuma Naoki , Kainoh Mie , Tanaka Toshiaki , Satoh Kaneo , Ozaki Yukio 
Published: October 2002

AbstractIn this study, the receptors and signals involved in collagen-induced platelet spreading were examined. It was found that platelet spreading on collagen (presenting a polygon shape with a number of filopodialike projections) was inhibited by the anti–integrin α2 antibody, suggesting the involvement of integrin α2β1 in this process. Studies with a glutathione-S-transferase fusion protein that binds specifically to activated Rac and in vitro p21-activated kinase (PAK) kinase assays revealed that Rac and PAK were activated during this collagen-activated process. Platelet spreading on collagen-coated surfaces was inhibited strongly by PP1 (a Src family kinase inhibitor) or weakly by wortmannin (a phosphatidylinositol 3-kinase [PI3-kinase] inhibitor) but not at all by Y-27632 (a Rho kinase inhibitor). The surfaces coated with anti–integrin α2β1antibodies also induced platelet spreading (presenting an almost complete round shape) and activation of Rac and PAK, although more slowly than collagen-coated surfaces. The antibody-induced responses were strongly inhibited by PP1 or wortmannin but not by Y-27632. The same concentration of Y-27632 inhibited collagen-induced shape change of platelets in suspension. These findings suggest that Rac and/or PAK activation, but not Rho, may play certain roles in platelet spreading via integrin α2β1 and that Src family kinases and PI3-kinase participate in these processes. Furthermore, the difference between spreading on collagen and the anti-integrin antibody suggests the involvement of other receptor(s) (in addition to the integrin α2β1) for collagen-induced spreading, the most likely candidate being glycoprotein VI.
The normal cellular prion protein is strongly expressed by myeloid dendritic cells
Authors: Burthem John , Urban Britta , Pain Arnab , Roberts David J. 
Published: October 2002

AbstractAbnormal isoforms of the prion protein (PrPSc) that cause prion diseases are propagated and spread within the body by “carrier” cell(s). Cells of the immune system have been strongly implicated in this process. In particular, PrPSc is known to accumulate on follicular dendritic cells (FDCs) in individuals affected by variant Creutzfeld-Jakob disease. However, FDCs do not migrate widely and the natural history of prion disorders suggests other cells may be required for the transport of PrPSc from the site of ingestion to lymphoid organs and the central nervous system. Substantial evidence suggests that the spread of PrPSc requires bone marrow-derived cells that express normal cellular prion protein (PrPC). This study examined the expression of PrPC on bone marrow–derived cells that interact with lymphoid follicles. High levels of PrPC are present on myeloid dendritic cells (DCs) that surround the splenic white pulp. These myeloid DCs are ontologically and functionally distinct from the FDCs. Consistent with these observations, expression of PrPC was strongly induced during the generation of mature myeloid DCs in vitro. In these cells PrPCcolocalized with major histocompatibility complex class II molecules at the level of light microscopy. Furthermore, given the close anatomic and functional connection of myeloid DCs with lymphoid follicles, these results raise the possibility that myeloid DCs may play a role in the propagation of PrPSc in humans.
Asymptomatic primary Epstein-Barr virus infection occurs in the absence of blood T-cell repertoire perturbations despite high levels of systemic viral load
Authors: Silins Sharon L. , Sherritt Martina A. , Silleri Jodie M. , Cross Simone M. , Elliott Suzanne L. , Bharadwaj Mandvi , Le Thuy T. T. , Morrison Leanne E. , Khanna Rajiv , Moss Denis J. , Suhrbier Andreas , Misko Ihor S. 
Published: October 2002

AbstractPrimary infection with the human herpesvirus, Epstein-Barr virus (EBV), may result in subclinical seroconversion or may appear as infectious mononucleosis (IM), a lymphoproliferative disease of variable severity. Why primary infection manifests differently between patients is unknown, and, given the difficulties in identifying donors undergoing silent seroconversion, little information has been reported. However, a longstanding assumption has been held that IM represents an exaggerated form of the virologic and immunologic events of asymptomatic infection. T-cell receptor (TCR) repertoires of a unique cohort of subclinically infected patients undergoing silent infection were studied, and the results highlight a fundamental difference between the 2 forms of infection. In contrast to the massive T-cell expansions mobilized during the acute symptomatic phase of IM, asymptomatic donors largely maintain homeostatic T-cell control and peripheral blood repertoire diversity. This disparity cannot simply be linked to severity or spread of the infection because high levels of EBV DNA were found in the blood from both types of acute infection. The results suggest that large expansions of T cells within the blood during IM may not always be associated with the control of primary EBV infection and that they may represent an overreaction that exacerbates disease.
The B-cell receptor of a hepatitis C virus (HCV)–associated non-Hodgkin lymphoma binds the viral E2 envelope protein, implicating HCV in lymphomagenesis
Authors: Quinn Elizabeth R. , Chan Chunghuang Hubert , Hadlock Kenneth G. , Foung Steven K. H. , Flint Mike , Levy Shoshana 
Published: October 2002

Abstract
Hepatitis C virus (HCV) infection is associated with extrahepatic B-cell lymphoproliferative disorders. To determine whether a viral antigen drives this B-cell expansion, the B-cell receptors were cloned from HCV-associated lymphomas and were expressed as soluble immunoglobulins. The rescued immunoglobulins were then tested for their ability to bind the HCV-E2 envelope glycoprotein, an antigen that was previously implicated in the pathogenesis of HCV-associated B-cell diseases. One of 2 lymphoma immunoglobulin test cases bound the E2 protein in a manner identical to a bona fide human anti-E2 antibody. Moreover, it bound E2 from multiple viral genotypes, suggesting reactivity with a conserved E2 epitope. These findings support the hypothesis that some HCV-associated lymphomas originate from B cells that were initially activated by the HCV-E2 protein and might explain the association between HCV infection and some B-cell lymphoproliferative disorders.
Simian immunodeficiency virus (SIV)–specific cytotoxic T lymphocytes in gastrointestinal tissues of chronically SIV-infected rhesus monkeys
Authors: Schmitz Jörn E. , Veazey Ronald S. , Kuroda Marcelo J. , Levy Daniel B. , Seth Aruna , Mansfield Keith G. , Nickerson Christine E. , Lifton Michelle A. , Alvarez Xavier , Lackner Andrew A. , Letvin Norman L. 
Published: October 2002

AbstractAlthough systemic virus-specific cytotoxic T lymphocyte (CTL) responses are of critical importance in controlling virus replication in individuals infected with human immunodeficiency virus 1 (HIV-1), little is known about this immune response in the gastrointestinal (GI) tract. This study investigated the GI tract CTL response in a nonhuman primate model for HIV-1 infection, simian immunodeficiency virus (SIV)–infected rhesus monkeys. Lymphocytes from duodenal pinch biopsy specimens were obtained from 9 chronically SIVmac-infected rhesus monkeys and GI tract lymphocytes were harvested from the jejunum and ileum of 4 euthanized SIVmac-infected rhesus monkeys. Lymphocytes were also assessed in GI mucosal tissues by in situ staining in histologic specimens. SIVmac Gag-specific CTLs were assessed in the monkeys using the tetramer technology. These GI mucosal tissues of chronically SIVmac-infected rhesus monkeys contained levels of CTLs comparable to those found in the peripheral blood and lymph nodes. The present studies suggest that the CD8+ CTL response in GI mucosal sites is comparable to that seen systemically in SIVmac-infected rhesus monkeys.