Abstract:
:We show that supercoiling of a DNA trefoil, the simplest knotted ring, perturbs differently the spatial writhe of its two chiral forms. As a consequence, the negative-noded and positive-noded DNA trefoils can be resolved by gel electrophoresis. Analysis of the chirality of trefoils produced by cyclization of two linear DNAs demonstrates that the two chiral trefoils are produced in equal amounts, suggesting that these DNAs do not prefer intrinsic writhe of one chirality or the other. In contrast, knotting of nicked DNA rings by a molar excess of Saccharomyces cerevisiae DNA topoisomerase II produces more negative-noded than positive-noded trefoils, indicating an asymmetry in the interaction between the enzyme and DNA crossovers of different signs. These results suggest that asymmetry in DNA crossovers and intrinsic or ligand-induced writhe in a DNA might be detectable from an analysis of trefoil chirality.
journal_name
Proc Natl Acad Sci U S Aauthors
Shaw SY,Wang JCdoi
10.1073/pnas.94.5.1692subject
Has Abstractpub_date
1997-03-04 00:00:00pages
1692-7issue
5eissn
0027-8424issn
1091-6490journal_volume
94pub_type
杂志文章abstract::Reduced functional bladder capacity and concomitant increased micturition frequency (pollakisuria) are common lower urinary tract symptoms associated with conditions such as cystitis, prostatic hyperplasia, neurological disease, and overactive bladder syndrome. These symptoms can profoundly affect the quality of life ...
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.1005333107
更新日期:2010-11-02 00:00:00
abstract::Addition of antisense oligonucleotides to cell cultures has been used to specifically inhibit gene expression. We have investigated the mechanism by which oligonucleotides enter living cells. These compounds are taken up by cells in a saturable, size-dependent manner compatible with receptor-mediated endocytosis. Poly...
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.86.10.3474
更新日期:1989-05-01 00:00:00
abstract::We present whole-genome assemblies of four divergent Arabidopsis thaliana strains that complement the 125-Mb reference genome sequence released a decade ago. Using a newly developed reference-guided approach, we assembled large contigs from 9 to 42 Gb of Illumina short-read data from the Landsberg erecta (Ler-1), C24,...
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.1107739108
更新日期:2011-06-21 00:00:00
abstract::A topological model of the DNA binding site for the cyclic AMP receptor protein (CRP) is presented. A consensus sequence drawn from the known CRP binding sites has several symmetrical subregions that are spatially resolved onto different faces of the DNA helix. Consideration of available biochemical and genetic data 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.78.4.2213
更新日期:1981-04-01 00:00:00
abstract::The application of boron neutron capture therapy to rheumatoid arthritis requires the selective delivery of the boron-10 isotope to the synovitic tissue. The use of liposomes as a boron delivery method has been explored through the measurement of the time course biodistribution of boron in rats with collagen-induced 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.95.5.2531
更新日期:1998-03-03 00:00:00
abstract::Although Hedgehog (Hh) signaling regulates cell differentiation during pancreas organogenesis, the consequences of pathway up-regulation in adult β-cells in vivo have not been investigated. Here, we elevate Hh signaling in β-cells by expressing an active version of the GLI2 transcription factor, a mediator of the Hh 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.1105404108
更新日期:2011-10-11 00:00:00
abstract::A key component of scientific communication is sufficient information for other researchers in the field to reproduce published findings. For computational and data-enabled research, this has often been interpreted to mean making available the raw data from which results were generated, the computer code that generate...
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.1708290115
更新日期:2018-03-13 00:00:00
abstract::Genes that are unexpressed in somatic cells have been activated by injecting cultured cell nuclei of the frog Xenopus laevis into oocytes of the newt Pleurodeles waltlii. The genes that were activated are normally expressed in oocytes but not in cultured cells. Conversely, genes that are normally expressed in cultured...
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.74.6.2470
更新日期:1977-06-01 00:00:00
abstract::One of the ultimate objectives of de novo protein design is to realize systems capable of catalyzing redox reactions on substrates. This goal is challenging as redox-active proteins require design considerations for both the reduced and oxidized states of the protein. In this paper, we describe the spectroscopic chara...
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.1212893110
更新日期:2012-12-26 00:00:00
abstract::Societies are complex systems, which tend to polarize into subgroups of individuals with dramatically opposite perspectives. This phenomenon is reflected-and often amplified-in online social networks, where, however, humans are no longer the only players and coexist alongside with social bots-that is, software-control...
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.1803470115
更新日期:2018-12-04 00:00:00
abstract::The plasma membrane (PM) is composed of heterogeneous subdomains, characterized by differences in protein and lipid composition. PM receptors can be dynamically sorted into membrane domains to underpin signaling in response to extracellular stimuli. In plants, the plasmodesmal PM is a discrete microdomain that hosts 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.1907799117
更新日期:2020-04-28 00:00:00
abstract::SLAM (signaling lymphocyte activation molecule)-associated protein (SAP) is a Src homology 2 (SH2) domain-containing adaptor expressed in T cells and natural killer cells. Its essential role in immune responses is underscored by the recent finding that mutations in SAP result in a rare but fatal X-linked lymphoprolife...
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.0606624103
更新日期:2006-09-26 00:00:00
abstract::A recently discovered family of natural anion channelrhodopsins (ACRs) have the highest conductance among channelrhodopsins and exhibit exclusive anion selectivity, which make them efficient inhibitory tools for optogenetics. We report analysis of flash-induced absorption changes in purified wild-type and mutant ACRs,...
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.1525269113
更新日期:2016-04-05 00:00:00
abstract::Obesity is associated with increased risk for developing pancreatic cancer, and it is suggested that insulin resistance provides the missing link. Here we demonstrate that under the context of genetic susceptibility, a high fat diet (HFD) predisposes mice with oncogenic K-ras activation to accelerated pancreatic intra...
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.0802864106
更新日期:2009-03-03 00:00:00
abstract::Several natural isolate E. coli strains highly resistant to sulfonamides and antibiotics are shown to contain a sulfonamide-resistant dihydropteroate synthase (2-amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine-diphosphate:4-aminobenzoate 2-amino-4-hydroxydihydropteridine-6-methenyltransferase, EC 2.5.1.15) in add...
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.72.7.2621
更新日期:1975-07-01 00:00:00
abstract::Recent research links diet-induced obesity (DIO) with impaired immunity, although the underlying mechanisms remain unclear. We find that the induction of inducible NO synthase (iNOS) and cytokines is suppressed in mice with DIO and in bone marrow macrophages (BMMPhi) from mice with DIO exposed to an oral pathogen, Por...
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.0904412106
更新日期:2009-06-30 00:00:00
abstract::Ubiquitination, the crucial posttranslational modification that regulates the eukaryotic proteome, is carried out by a trio of enzymes, known as E1 [ubiquitin (Ub)-activating enzyme], E2 (Ub-conjugating enzyme), and E3 (Ub ligase). Although most E2s can work with any of the three mechanistically distinct classes of E3...
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.1705060114
更新日期:2017-08-08 00:00:00
abstract::We have identified a murine gene, metaxin, that spans the 6-kb interval separating the glucocerebrosidase gene (GC) from the thrombospondin 3 gene on chromosome 3E3-F1. Metaxin and GC are transcribed convergently; their major polyadenylylation sites are only 431 bp apart. On the other hand, metaxin and the thrombospon...
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.92.10.4547
更新日期:1995-05-09 00:00:00
abstract::Many groups of insects are specialists in exploiting sensory cues to locate food resources or conspecifics. To achieve orientation, bees and ants analyze the polarization pattern of the sky, male moths orient along the females' odor plume, and cicadas, grasshoppers, and crickets use acoustic signals to locate singing ...
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.0505282102
更新日期:2005-10-25 00:00:00
abstract::The spleen from a patient with adult Gaucher's disease was shown to be deficient in a beta-glucosidase (EC 3.2.1.21) isoenzyme that has optimal activity at pH 4.0-4.3, and is stimulated by 0.02% Triton X-100. A mixture of spleen homogenates from a control and from the patient contained beta-glucosidase activity equiva...
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.68.11.2810
更新日期:1971-11-01 00:00:00
abstract::A human craniofacial cDNA library was screened with a degenerate oligonucleotide probe based on the conserved third helix of homeobox genes. From this screening, we identified a homeobox gene, H6, which shared only 57-65% amino acid identity to previously reported homeodomains. H6 was physically mapped to the 4p16.1 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.89.23.11579
更新日期:1992-12-01 00:00:00
abstract::The vaccinia virus early transcription factor (VETF), a heterodimeric protein composed of 82- and 70-kDa subunits, interacts with viral early promoters at both a sequence-specific core region upstream and a sequence-independent region downstream of the RNA start site. To determine the VETF subunit-promoter interaction...
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.93.15.7540
更新日期:1996-07-23 00:00:00
abstract::Egg laying hormone, a peptide neurohormone with an approximate molecular weight of 6000, was isolated from the region of the abdominal ganglion of Aplysia that contains the neuroendocrine bag cells and purified by gel filtration chromatography, isoelectric focusing, and dialysis. A 1-min local application of egg layin...
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.75.11.5732
更新日期:1978-11-01 00:00:00
abstract::A key barrier to the realization of personalized medicine for cancer is the identification of biomarkers. Here we describe a two-stage strategy for the discovery of serum biomarker signatures corresponding to specific cancer-causing mutations and its application to prostate cancer (PCa) in the context of the commonly ...
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.1013699108
更新日期:2011-02-22 00:00:00
abstract::Aminoglycoside ototoxicity has been related to a surprisingly large number of cellular structures and metabolic pathways. The finding that patients with mutations in mitochondrial rRNA are hypersusceptible to aminoglycoside-induced hearing loss has indicated a possible role for mitochondrial protein synthesis. To stud...
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.0811258106
更新日期:2008-12-30 00:00:00
abstract::According to a current "RNA first" model for the origin of life, RNA emerged in some form on early Earth to become the first biopolymer to support Darwinism here. Threose nucleic acid (TNA) and other polyelectrolytes are also considered as the possible first Darwinian biopolymer(s). This model is being developed by re...
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.1710778114
更新日期:2017-10-24 00:00:00
abstract::The mammalian retina contains an autonomous circadian clock system that controls many physiological functions within this tissue. Previous studies on young mice have reported that removal of the key circadian clock gene Bmal1 from the retina affects the circadian regulation of visual function, but does not affect phot...
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.1808137115
更新日期:2018-12-18 00:00:00
abstract::Ca2+ ions control the cGMP-gated channel of rod photoreceptor cells from the external and internal face. We studied ion selectivity and blockage by Ca2+ of wild-type and mutant channels in a heterologous expression system. External Ca2+ blocks the inward current at micromolar concentrations in a highly voltage-depende...
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.91.3.1109
更新日期:1994-02-01 00:00:00
abstract::The amino acid sequence of the light chain of bovine protein C was determined by sequenator analysis of the carboxymethylated light chain and fragments obtained by cyanogen bromide treatment, tryptic digestion after blocking of lysine residues, and cleavage with 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine (BN...
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.75.12.5889
更新日期:1978-12-01 00:00:00
abstract::The tumor microenvironment restrains conventional T cell (Tconv) activation while facilitating the expansion of Tregs. Here we showed that Tregs' advantage in the tumor milieu relies on supplemental energetic routes involving lipid metabolism. In murine models, tumor-infiltrating Tregs displayed intracellular lipid ac...
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.1720113115
更新日期:2018-07-10 00:00:00