Abstract:
:For study of the basis of an X-linked form of gout in man, several clonal lines deficient in hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) were selected from the human lymphoblast line WI-L2 by spontaneous and mutagen-induced resistance to 10 muM 8-azaguanine. Three groups could be defined: (1) clones with less than 1% of normal enzyme activity, unable to incorporate [(3)H]hypoxanthine detectable by radioautography, unable to tuilize exogenous hypoxanthine as a source of purines, and showing a 2- to 4-fold accelerated rate of production of early intermediates in de novo purine biosynthesis; (2) clones with 56-63% of normal enzyme activity, decreased incorporation per cell of [(3)H]hypoxanthine measured by radioautography, able to utilize exogenous hypoxanthine, and showing 1.2- to 2.8-fold purine overproduction; (3) clones with 10-15% of normal enzyme activity, able to utilize hypoxanthine but not incorporating amounts detectable by radioautography, and showing a 2.3- to 2.5-fold increase in purine biosynthesis. Resistant clones generated by ICR 191 mutagenesis resembled Group 1 clones. Heat inactivation studies in crude extracts from certain clones in Group 2 suggest a structural gene mutation, but no qualitative alteration in enzyme could be detected by starch gel electrophoresis. These phenotypes have persisted over at least 300 generations of nonselective growth, with retention of a diploid karyotype.
journal_name
Proc Natl Acad Sci U S Aauthors
Lever JE,Nuki G,Seegmiller JEdoi
10.1073/pnas.71.7.2679subject
Has Abstractpub_date
1974-07-01 00:00:00pages
2679-83issue
7eissn
0027-8424issn
1091-6490journal_volume
71pub_type
杂志文章abstract::Pancreatic ductal adenocarcinoma (PDAC) cells (PCC) have an exceptional propensity to metastasize early into intratumoral, chemokine-secreting nerves. However, we hypothesized the opposite process, that precancerous pancreatic cells secrete chemokines that chemoattract Schwann cells (SC) of nerves and thus induce read...
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.1606909114
更新日期:2017-01-03 00:00:00
abstract::Gene transfer into early embryos is a powerful methodology for unraveling the molecular bases of developmental processes. One can attempt to minimize widespread effects of an exogenous gene by using tissue- or region-specific promoters in the few instances where they are available. We have developed a method that bypa...
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.90.6.2350
更新日期:1993-03-15 00:00:00
abstract::The effect of pressure up to 175 kilobars on the electronic structure of three ferric hydroxamates and on ferrichrome A has been studied by optical absorption and Mössbauer resonance. The ferric ion was reduced to ferrous ion with pressure, as has been previously observed for various compounds. For the hydroxamates, t...
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.68.3.549
更新日期:1971-03-01 00:00:00
abstract::An automatic protein design procedure is used to select amino acid sequences that optimize the folding free energy function for a given protein. The only information used in designing the sequences is a set of known backbone structures for each protein, a rotamer library, and a well established classical empirical for...
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.212068599
更新日期:2002-10-15 00:00:00
abstract::Myosin VI is a molecular motor implicated in many processes, and it likely associates with a variety of cargoes that specify its functions. Although it is critical to Drosophila development, little is known about its cellular roles. To reveal its involvement in specific pathways, we sought to identify the binding part...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1101415108
更新日期:2011-04-05 00:00:00
abstract::We have isolated an Arabidopsis thaliana gene that codes for a receptor related to antifungal pathogenesis-related (PR) proteins. The PR5K gene codes for a predicted 665-amino acid polypeptide that comprises an extracellular domain related to the PR5 proteins, a central transmembrane-spanning domain, and an intracellu...
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.93.6.2598
更新日期:1996-03-19 00:00:00
abstract::Chemical genomics is a powerful approach to dissect processes that may be intractable using conventional genetics because of gene lethality or redundancy. Recently, a link has been established between endomembrane trafficking and gravitropism. To understand this link, we screened a library of 10,000 diverse chemicals ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.0500222102
更新日期:2005-03-29 00:00:00
abstract::The genomic concentrations of certain middle repetitive DNA sequences vary considerably among closely related species of Drosophila. In fact, the chromosomes of D. melanogaster appear to carry approximately 3 times as much middle repetitive DNA as those of the sibling species D. simulans. Although most of the middle r...
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.79.15.4570
更新日期:1982-08-01 00:00:00
abstract::Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/C(CDC20) activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/...
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.1604929113
更新日期:2016-05-10 00:00:00
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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.182552199
更新日期:2002-10-29 00:00:00
abstract::Asymmetric cell division (ACD) is believed to be a physiological event that occurs during development and tissue homeostasis in a large variety of organisms. ACD produces two unequal daughter cells, one of which resembles a multipotent stem and/or progenitor cell, whereas the other has potential for differentiation. A...
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.1205525109
更新日期:2012-10-30 00:00:00
abstract::Positive allosteric modulation of the mu-opioid receptor (MOPr), the site of action of all clinically used opioids, represents a potential approach for the management of pain. We recently reported on positive allosteric modulators of MOPr (mu-PAMs), a class A G protein coupled receptor (GPCR). This study was designed ...
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.1415013111
更新日期:2014-12-23 00:00:00
abstract::An in vitro enzyme system for the conversion of amino acid to oxime in the biosynthesis of glucosinolates has been established by the combined use of an improved isolation medium and jasmonic acid-induced etiolated seedlings of Sinapis alba L. An 8-fold induction of de novo biosynthesis of the L-tyrosine-derived p-hyd...
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.92.26.12505
更新日期:1995-12-19 00:00:00
abstract::Acquisition of acetylcholine receptors during differentiation of a clonal myoblast cell line was monitored with a neurotoxin isolated from venom of the Indian Cobra Naja naja. Toxin bound specifically and reversibly to acetylcholine receptors of the differentiated cells. Specificity of the binding reaction was assayed...
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.69.10.2762
更新日期:1972-10-01 00:00:00
abstract::Plasma membrane fractions from Xenopus laevis oocytes were incorporated into planar lipid bilayers. We show the existence of numerous Ca2+-activated nonspecific channels that are more permeable to anions. These channels are activated by Ca2+ at micromolar concentration but not by Mg2+, Zn2+, or Mn2+, even at millimola...
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.81.16.5155
更新日期:1984-08-01 00:00:00
abstract::The synthesis of graphene materials is typically carried out by oxidizing graphite to graphite oxide followed by a reduction process. Numerous methods exist for both the oxidation and reduction steps, which causes unpredictable contamination from metallic impurities into the final material. These impurities are known ...
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.1413389111
更新日期:2014-09-23 00:00:00
abstract::Influenza virus neuraminidase (NA; EC 3.2.1.18) possesses a signal-anchor hydrophobic domain at the amino terminus. To characterize the nature of this signal-anchor domain we have introduced single amino acid changes in this domain by oligonucleotide-directed mutagenesis. Three mutant NA proteins that were synthesized...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.84.1.1
更新日期:1987-01-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2011-02-08 00:00:00
abstract::Epstein-Barr virus (EBV), an oncogenic herpesvirus, encodes two small RNAs (EBERs) that are expressed at high levels during latent transformation of human B lymphocytes. Here we report that a 15-kDa cellular protein called EAP (for EBER associated protein), previously shown to bind EBER1, is in fact the ribosomal prot...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.91.8.3463
更新日期:1994-04-12 00:00:00
abstract::In classical evolutionary theory, traits evolve because they facilitate organismal survival and/or reproduction. We discuss a different type of evolutionary mechanism that relies upon differential dispersal. Traits that enhance rates of dispersal inevitably accumulate at expanding range edges, and assortative mating b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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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.81.14.4381
更新日期:1984-07-01 00:00:00
abstract::We estimated the unliganded opening and closing rate constants of neuromuscular acetylcholine receptor-channels (AChRs) having mutations that increased the gating equilibrium constant. For some mutant combinations, spontaneous openings occurred in clusters. For 25 different constructs, the unliganded gating equilibriu...
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.0809272106
更新日期:2009-01-06 00:00:00
abstract::When infants and adults communicate, they exchange social signals of availability and communicative intention such as eye gaze. Previous research indicates that when communication is successful, close temporal dependencies arise between adult speakers' and listeners' neural activity. However, it is not known whether 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.1702493114
更新日期:2017-12-12 00:00:00
abstract::The observation that the age-specific incidence curve of many carcinomas is approximately linear on a double logarithmic plot has led to much speculation regarding the number and nature of the critical events involved in carcinogenesis. By a consideration of colorectal and pancreatic cancers in the Surveillance Epidem...
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.0801151105
更新日期:2008-10-21 00:00:00
abstract::Glucose stimulates insulin secretion from β-cells by increasing intracellular Ca(2+). Ca(2+) then binds to synaptotagmin-7 as a major Ca(2+) sensor for exocytosis, triggering secretory granule fusion and insulin secretion. In type-2 diabetes, insulin secretion is impaired; this impairment is ameliorated by glucagon-li...
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.1513004112
更新日期:2015-08-11 00:00:00
abstract::Mutations in the potassium channel gene KCNQ4 underlie DFNA2, an autosomal dominant form of progressive hearing loss in humans. In the mouse cochlea, the transcript has been found exclusively in the outer hair cells. By using specific antibodies, we now show that KCNQ4 is situated at the basal membrane of these sensor...
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.97.8.4333
更新日期:2000-04-11 00:00:00
abstract::The high-potential iron-sulfur center associated with the g = 1.89-1.90 electron paramagnetic resonance signal in spinach chloroplasts is fully reduced in the dark. It is photooxidized in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea and reduced after illumination with red actinic light in the absence of inh...
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.76.9.4417
更新日期:1979-09-01 00:00:00
abstract::It is well established that pregnancy early in life reduces the risk of breast cancer in women and that this effect is universal. This phenomenon of parity protection against mammary cancer is also observed in rodents. Earlier studies have demonstrated that short-term administration of estradiol (E) in combination wit...
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.201393798
更新日期:2001-09-25 00:00:00
abstract::Cellular differentiation leading to formation of the bradyzoite tissue cyst stage is the underlying cause of chronic toxoplasmosis. Consequently, mechanisms responsible for controlling development in the Toxoplasma intermediate life cycle have long been sought. Here, we identified 15 Toxoplasma mRNAs induced in early ...
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.1300059110
更新日期:2013-04-23 00:00:00
abstract::Euarthropoda is one of the best-preserved fossil animal groups and has been the most diverse animal phylum for over 500 million years. Fossil Konservat-Lagerstätten, such as Burgess Shale-type deposits (BSTs), show the evolution of the euarthropod stem lineage during the Cambrian from 518 million years ago (Ma). The 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.1719962115
更新日期:2018-05-22 00:00:00