Abstract:
:Gene amplification may be visualized within a chromosome as a homogeneously stained region (HSR) and HSRs have rarely been reported in human tumor cells with identification of the amplified gene. A parental line and seven clones derived from KB cells resistant to methotrexate (MTX) contain dihydrofolate reductase (DHFR; tetrahydrofolate dehydrogenase; EC 1.5.1.3), ranging from 0.007 unit/mg in the parent to 0.369 unit/mg in clone 7A with a 13,000-fold increase in resistance to MTX. The enzyme is identical to DHFR from other human sources, including that from leukemic patients. A HSR localized to the long arm of chromosome 10(q26) is present in clones selected at or above 2.5 microM MTX. Increase in number of 10q per cell, increase in number of HSR, and increasing amounts of DHFR correlate well. The chromosome change is stable with time as is enzyme production even in the absence of selection by MTX. No clone has shown double minutes. The gene copy number is low. The stability and low gene copy in the presence of large HSRs differ from the pattern described for murine tumors. A human gene for DHFR may be associated with the long arm of chromosome 10.
journal_name
Proc Natl Acad Sci U S Aauthors
Wolman SR,Craven ML,Grill SP,Domin BA,Cheng YCdoi
10.1073/pnas.80.3.807subject
Has Abstractpub_date
1983-02-01 00:00:00pages
807-9issue
3eissn
0027-8424issn
1091-6490journal_volume
80pub_type
杂志文章abstract::The cytoplasmic Myc protein (c-Myc) regulates various human genes and is dysregulated in many human cancers. Phosphorylation mediates the protein activation of c-Myc and is essential for the function of this transcription factor in normal cell behavior and tumor growth. To date, however, the targeting of Myc as a ther...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1007443107
更新日期:2010-09-07 00:00:00
abstract::A typical homing endonuclease initiates mobility of its group I intron by recognizing DNA both upstream and downstream of the intron insertion site of intronless alleles, preventing the endonuclease from binding and cleaving its own intron-containing allele. Here, we describe a GIY-YIG family homing endonuclease, I-Bm...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.141222498
更新日期:2001-07-03 00:00:00
abstract::Visual transduction in Drosophila is a G protein-coupled phospholipase C-mediated process that leads to depolarization via activation of the transient receptor potential (TRP) calcium channel. Inactivation-no-afterpotential D (INAD) is an adaptor protein containing PDZ domains known to interact with TRP. Immunoprecipi...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.23.12682
更新日期:1997-11-11 00:00:00
abstract::Esterase 6 is a polymorphic carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1) localized to the reproductive tract of male Drosophila melanogaster and transferred to females at copulation. The reproductive fitness of males is strongly affected by temperature and the esterase 6 alleles (active versus null) that ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.79.9.2962
更新日期:1982-05-01 00:00:00
abstract::The ability of beta cells to endure assaults may be relevant in the development of insulin-dependent diabetes mellitus. This study examines the susceptibility of human pancreatic islets to agents that are cytotoxic for rodent beta cells--i.e., sodium nitroprusside (NP, a nitric oxide donor), streptozotocin (SZ), or al...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.20.9253
更新日期:1994-09-27 00:00:00
abstract::We propose a phenomenological theory that accounts for entropic effects due to loop formation to predict pathways in the kinetics of protein folding. The theory, the basis of which lies in multiple folding pathways and a three-stage kinetics, qualitatively reproduces most of the kinetic measurements in the refolding o...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.5.1277
更新日期:1995-02-28 00:00:00
abstract::Aortic endothelial cells from normal pigs and pigs with von Willebrand disease have been established in long-term cultures. Both cultures appeared similar in terms of general growth characteristics, morphologic features and ultrastructure. Immunofluorescent staining of these cultures with chicken (or rabbit) antiporci...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.74.12.5702
更新日期:1977-12-01 00:00:00
abstract::The DNA strand exchange protein RAD51 facilitates the central step in homologous recombination, a process fundamentally important for accurate repair of damaged chromosomes, restart of collapsed replication forks, and telomere maintenance. The active form of RAD51 is a nucleoprotein filament that assembles on single-s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1604807113
更新日期:2016-10-11 00:00:00
abstract::Although aminoacyl-tRNA synthetases (ARSs) are essential for protein synthesis, they also function as regulators and signaling molecules in diverse biological processes. Here, we screened 11 different human ARSs to identify the enzyme that is secreted as a signaling molecule. Among them, we found that lysyl-tRNA synth...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0500226102
更新日期:2005-05-03 00:00:00
abstract::Capturing carbon dioxide from the atmosphere ("air capture") in an industrial process has been proposed as an option for stabilizing global CO(2) concentrations. Published analyses suggest these air capture systems may cost a few hundred dollars per tonne of CO(2), making it cost competitive with mainstream CO(2) miti...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1012253108
更新日期:2011-12-20 00:00:00
abstract::Neutrophil spontaneous death plays essential roles in neutrophil homeostasis and resolution of inflammation, whereas the underlying molecular mechanisms are still ill-defined. Neutrophils die because of programmed cell death or apoptosis. However, treatment with inhibitor of caspases, which are responsible for the maj...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0605722103
更新日期:2006-10-03 00:00:00
abstract::Many current treatments for the reclamation of contaminated water sources are chemical-intensive, energy-intensive, and/or require posttreatment due to unwanted by-product formation. We demonstrate that through the integration of nanostructured materials, enzymatic catalysis, and iron-catalyzed free radical reactions ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1101144108
更新日期:2011-05-24 00:00:00
abstract::Differences in T cell receptor (TCR) signaling initiated by interactions among TCRs, coreceptors, and self-peptide-MHC complexes determine the outcome of CD4 versus CD8 lineage of T cell differentiation. The H-2Ld and Kbm3 alloreactive 2C TCR is positively selected by MHC class I Kb and a yet-to-be identified nonclass...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0510561103
更新日期:2006-02-07 00:00:00
abstract::Significant attention has focused on the role of low-density lipoprotein (LDL) in the pathogenesis of atherosclerosis. However, recent advances have identified triglyceride-rich lipoproteins [e.g., very LDL (VLDL)] as independent risk predictors for this disease. We have previously demonstrated peroxisome proliferator...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0510815103
更新日期:2006-02-14 00:00:00
abstract::Transient cytosolic Ca(2+) ([Ca(2+)](cyt)) elevations are early events in plant signaling pathways including those related to abiotic stress. The restoration of [Ca(2+)](cyt) to prestimulus levels involves ATP-driven Ca(2+) pumps, but direct evidence for an essential role of a plant Ca(2+)-ATPase in abiotic stress ada...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0800864105
更新日期:2008-12-09 00:00:00
abstract::A plasmid containing the rat preproinsulin I gene was entrapped in large liposomes and intravenously administered to rats. Four hours after inoculation, the livers were processed for the isolation of hepatocytes. Kupffer cells, and endothelial cells, DNA was purified, and the exogenous DNA was detected in the differen...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.23.7128
更新日期:1983-12-01 00:00:00
abstract::Herpes simplex virus type 2 (HSV-2) DNA was treated with four restriction endonucleases (EcoRI, HincIII, Bgl II, and Xba I) and eight fragments were purified and labeled with 32P in vitro. The kinetics of renaturation of each of the fragments was measured in the presence of DNA extracted from 333-8-9, a hamster cell l...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.77.2.880
更新日期:1980-02-01 00:00:00
abstract::Biocompatible gold nanoparticles designed to absorb light at wavelengths of high tissue transparency have been of particular interest for biomedical applications. The ability of such nanoparticles to convert absorbed near-infrared light to heat and induce highly localized hyperthermia has been shown to be highly effec...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1906929116
更新日期:2019-09-10 00:00:00
abstract::The proinflammatory cytokine interleukin 1 (IL-1) activates the transcription of many genes encoding acute phase and proinflammatory proteins, a function mediated primarily by the transcription factor NF-kappaB. An early IL-1 signaling event is the recruitment of the Ser/Thr kinase IRAK to the type I IL-1 receptor (IL...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.24.12829
更新日期:1997-11-25 00:00:00
abstract::The essential eukaryotic pre-mRNA splicing factor U2AF (U2 small nuclear ribonucleoprotein auxiliary factor) is required to specify the 3' splice at an early step in spliceosome assembly. U2AF binds site-specifically to the intron polypyrimidine tract and recruits U2 small nuclear ribonucleoprotein to the branch site....
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.19.10333
更新日期:1996-09-17 00:00:00
abstract::Adult rat arterial smooth muscle cells (SMC) in primary culture modulate from contractile to synthetic phenotype. This process includes partial loss of myofilaments and formation of an extensive rough endoplasmic reticulum and a large Golgi complex. It gives the cells the ability to initiate DNA synthesis and actively...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.13.4418
更新日期:1985-07-01 00:00:00
abstract::l-Serine biosynthesis, a crucial metabolic process in most domains of life, is initiated by d-3-phosphoglycerate (d-3-PG) dehydrogenation, a thermodynamically unfavorable reaction catalyzed by d-3-PG dehydrogenase (SerA). d-2-Hydroxyglutarate (d-2-HG) is traditionally viewed as an abnormal metabolite associated with c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1619034114
更新日期:2017-09-05 00:00:00
abstract::Previous reports have shown that γδ T cells are important for the elimination of malaria parasites in humans and mice. However, how γδ T cells are involved in protective immunity against blood-stage malaria remains unknown. We infected γδ T-cell-deficient (TCRδ-KO) mice and control wild-type mice with Plasmodium bergh...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1204480109
更新日期:2012-07-24 00:00:00
abstract::The immune response is normally controlled by regulatory T cells (Tregs). However, Treg deficits are found in autoimmune diseases, and therefore the induction of functional Tregs is considered a potential therapeutic approach for autoimmune disorders. The activation of the ligand-activated transcription factor aryl hy...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1120611109
更新日期:2012-07-10 00:00:00
abstract::Comparative genetic maps of Papuan Saccharum officinarum L. (2n = 80) and S. robustum (2n = 80) were constructed by using single-dose DNA markers (SDMs). SDM-framework maps of S. officinarum and S. robustum were compared with genetic maps of sorghum and maize by way of anchor restriction fragment length polymorphism p...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.26.14261
更新日期:1997-12-23 00:00:00
abstract::A 16-base-pair palindrome from the Agrobacterium tumefaciens octopine synthase gene functions as a constitutive enhancer in plant protoplasts. Degenerate oligonucleotide mutagenesis provided single base substitutions at every position in the element and a number of multiple base substitutions. The effects of these cha...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.10.3733
更新日期:1989-05-01 00:00:00
abstract::We completed the cDNA cloning and sequencing of gp330, the major kidney glomerular antigen for rat Heymann nephritis. The deduced 4660-aa sequence, expected to constitute a mature protein of M(r) 516,715, consists of a probable N-terminal signal peptide sequence (25 aa), an extracellular region (4400 aa), a single tra...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.21.9725
更新日期:1994-10-11 00:00:00
abstract::The dramatic loss of Kilimanjaro's ice cover has attracted global attention. The three remaining ice fields on the plateau and the slopes are both shrinking laterally and rapidly thinning. Summit ice cover (areal extent) decreased approximately 1% per year from 1912 to 1953 and approximately 2.5% per year from 1989 to...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0906029106
更新日期:2009-11-24 00:00:00
abstract::Phenylglyoxal is an arginine-specific reagent that inactivates creatine kinase (CK). Previous results suggest that modification of the dimeric enzyme at a single arginine residue per subunit causes complete inactivation accompanied by the loss of nucleotide binding; the actual site of modification was not identified. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.7.3362
更新日期:1998-03-31 00:00:00
abstract::Intracellular recordings were obtained from vagal neurons and their response to oxytocin was investigated in slices from the rat and the guinea pig brainstem. After recording, Lucifer yellow was injected into the cells to verify their localization within the dorsal motor nucleus of the vagus nerve (dmnX). In the rat, ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.11.3926
更新日期:1987-06-01 00:00:00