Abstract:
:Previous studies have shown that the helical RecA nucleoprotein filament formed on a circular single strand of DNA causes the progressive, directional transfer of a complementary strand from naked linear duplex DNA to the nucleoprotein filament, even when the duplex contains a sizable heterologous insertion. Since RecA protein lacks demonstrable helicase activity, the mechanism by which it pushes strand exchange through long heterologous inserts has been a quandary. In the present study, a linear duplex substrate with an insertion of 110 base pairs in its middle yielded the expected products, whereas much less of the heteroduplex product was seen when the insertion was located at either end of the duplex substrate or 160 base pairs from the far end of the duplex substrate. In an ongoing reaction of the substrate with an insertion in its middle, P1 nuclease cleaved intermediates from the point of the insertion to various distal sites. Acting on a duplex substrate that contained a single nick located in the complementary strand just beyond the insertion, RecA protein formed joint molecules but failed to complete strand exchange. These data show that negative torsional stress is generated by distant homologous interactions that occur beyond the heterologous insertion and that such stress is essential for unwinding a heterologous insertion that otherwise halts strand exchange.
journal_name
Proc Natl Acad Sci U S Aauthors
Jwang B,Radding CMdoi
10.1073/pnas.89.16.7596keywords:
subject
Has Abstractpub_date
1992-08-15 00:00:00pages
7596-600issue
16eissn
0027-8424issn
1091-6490journal_volume
89pub_type
杂志文章abstract::Metazoan embryogenesis is controlled by a limited number of signaling modules that are used repetitively at successive developmental stages. The development of social amoebas shows similar reiterated use of cAMP-mediated signaling. In the model Dictyostelium discoideum, secreted cAMP acting on 4 cAMP receptors (cARs1-...
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.0901617106
更新日期:2009-04-28 00:00:00
abstract::Under particular circumstances like lactation and fasting, the blood-borne monocarboxylates acetoacetate, beta-hydroxybutyrate, and lactate represent significant energy substrates for the brain. Their utilization is dependent on a transport system present on both endothelial cells forming the blood-brain barrier and 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.95.7.3990
更新日期:1998-03-31 00:00:00
abstract::The serine proteases sequentially activated to form a fibrin clot are inhibited primarily by members of the serpin family, which use a unique beta-sheet expansion mechanism to trap and destroy their targets. Since the discovery that serpins were a family of serine protease inhibitors there has been controversy as to 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.162232399
更新日期:2002-08-20 00:00:00
abstract::Future nuclear arms reduction efforts will require technologies to verify that warheads slated for dismantlement are authentic without revealing any sensitive weapons design information to international inspectors. Despite several decades of research, no technology has met these requirements simultaneously. Recent wor...
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.1721278115
更新日期:2018-04-24 00:00:00
abstract::Despite the increasing number of regulatory proteins identified in clathrin-independent endocytic (CIE) pathways, our understanding of the exact functions of these proteins and the sequential manner in which they function remains limited. In this study, using the Caenorhabditis elegans intestine as a model, we observe...
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.1408327111
更新日期:2014-10-28 00:00:00
abstract::Extragalactic X-ray surveys over the past decade have dramatically improved understanding of the majority populations of active galactic nuclei (AGNs) over most of the history of the universe. Here we briefly highlight some of the exciting discoveries about AGN demography, physics, and ecology, with a focus on results...
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.0914151107
更新日期:2010-04-20 00:00:00
abstract::The functional groups found among the RNA bases and in the phosphoribose backbone represent a limited repertoire from which to construct a ribozyme active site. This work investigates the possibility that simple RNA phosphodiester and hydroxyl functional groups could catalyze amide bond synthesis. Reaction of amine gr...
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.212527799
更新日期:2002-11-12 00:00:00
abstract::The processes of isolated rat sympathetic neurons growing in culture were marked with glass or carmine particles and observed with timelapse microphotography. Particles on the processes moved with the cell in relation to the dish and underwent continual small jerky movements. They did not, however, show any over-all d...
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.65.4.905
更新日期:1970-04-01 00:00:00
abstract::The central limit theorem is applied to group foraging to show an automatic and universal benefit to group living. This may explain the paradoxical inverse correlation between group size and per capita brood production in primitively eusocial insects and why only one of the five major lineages of social insects contai...
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.88.1.36
更新日期:1991-01-01 00:00:00
abstract::We introduced radioactive precursors directly into identified neurons of Aplysia californica. [(3)H]-Choline and L-[(3)H]tryptophan were injected with pressure into nerve cell bodies to study synthesis of acetylcholine and serotonin. We confirmed the cholinergic nature of R2, L10, and L11, identified neurons of the ab...
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.70.12.3371
更新日期:1973-12-01 00:00:00
abstract::Glutaredoxins (GRXs), also known as thioltransferases, use glutathione as a cofactor for reduction of disulfides in prokaryotes and eukaryotes. We demonstrate that the vaccinia virus O2L open reading frame encodes a functional GRX, as predicted by Johnson et al. [Johnson, G. P., Goebel, S. J., Perkus, M. E., Davis, 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.89.15.7060
更新日期:1992-08-01 00:00:00
abstract::Several lines of evidence suggest that the serotonin (5-hydroxytryptamine, 5-HT) regulates cardiovascular functions during embryogenesis and adulthood. 5-HT binds to numerous cognate receptors to initiate its biological effects. However, none of the 5-HT receptor disruptions in mice have yet resulted in embryonic defe...
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.97.17.9508
更新日期:2000-08-15 00:00:00
abstract::The role played by postsynaptic alpha-adrenergic receptors in the stimulation of pineal N-acetyltransferase (EC 2.3.1.5) and [3H]melatonin production was investigated in the rat. In vivo studies indicated that phenylephrine, an alpha-adrenergic agonist, potentiated and prolonged the effects of isoproterenol, a beta-ad...
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.80.2.599
更新日期:1983-01-01 00:00:00
abstract::Gene regulation by imposed localization was studied by using designed zinc finger proteins that bind 18-bp DNA sequences in the 5' untranslated regions of the protooncogenes erbB-2 and erbB-3. Transcription factors were generated by fusion of the DNA-binding proteins to repression or activation domains. When introduce...
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.040552697
更新日期:2000-02-15 00:00:00
abstract::Transfer of membrane between endoplasmic reticulum and Golgi apparatus in situ is considered to occur via 60-nm transition vesicles derived from part-rough, part-smooth transition elements of the endoplasmic reticulum. A procedure is described for the isolation of a fraction enriched in these transition elements from ...
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.84.17.6098
更新日期:1987-09-01 00:00:00
abstract::Drosophila ovo/svb (dovo) is required for epidermal cuticle/denticle differentiation and is genetically downstream of the wg signaling pathway. Similarly, a mouse homolog of dovo, movo1, is required for the proper formation of hair, a mammalian epidermal appendage. Here, we provide biochemical evidence that movo1 enco...
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.092137099
更新日期:2002-04-30 00:00:00
abstract::c-myc, N-myc, and L-myc genes are subject to highly variable degrees of tissue-specific regulation. Their aberrant expression has also been implicated in the pathogenesis of a variety of malignant tumors. The recently identified max protein dimerizes with c-myc to promote its sequence-specific DNA binding. max exists ...
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.90.3.960
更新日期:1993-02-01 00:00:00
abstract::The distribution of wealth in the United States and countries around the world is highly skewed. How does visible economic inequality affect well-off individuals' support for redistribution? Using a placebo-controlled field experiment, I randomize the presence of poverty-stricken people in public spaces frequented by ...
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.1615010113
更新日期:2017-01-24 00:00:00
abstract::A fundamental issue in human development concerns how the young infant's ability to recognize emotional signals is acquired through both biological programming and learning factors. This issue is extremely difficult to investigate because of the variety of sensory experiences to which humans are exposed immediately af...
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.142165999
更新日期:2002-06-25 00:00:00
abstract::l-tryptophan (Trp), an essential amino acid for mammals, is the precursor of a wide array of immunomodulatory metabolites produced by the kynurenine and serotonin pathways. The kynurenine pathway is a paramount source of several immunoregulatory metabolites, including l-kynurenine (Kyn), the main product of indoleamin...
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.1918215117
更新日期:2020-02-18 00:00:00
abstract::Alcohol exposure during development can cause brain malformations and neurobehavioral abnormalities. In view of the teratogenicity of ethanol, identification of molecules that could counteract the neurotoxic effects of alcohol deserves high priority. Here, we report that pituitary adenylate cyclase-activating polypept...
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.082112699
更新日期:2002-04-30 00:00:00
abstract::cDNA clones encoding a glutamic acid-rich protein were isolated from a bovine retina cDNA expression library. The cDNA sequence contained an open reading frame of 1770 base pairs encoding a protein of 590 amino acids (64,509 Da) and untranslated regions of 60 and 490 base pairs at the 5' and 3' ends, respectively. The...
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.88.8.3116
更新日期:1991-04-15 00:00:00
abstract::Transgenic mice have provided invaluable information about gene function and regulation. However, because of marked differences between rodents and primates, some areas of human biology such as early embryonic development, aging, and maternal-fetal interactions would be best studied in a nonhuman primate model. Here, ...
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.181336098
更新日期:2001-09-11 00:00:00
abstract::The membrane proteins of peripheral light-harvesting complexes (LHCs) bind chlorophylls and carotenoids and transfer energy to the reaction centers for photosynthesis. LHCs of chlorophytes, chromophytes, dinophytes, and rhodophytes are similar in that they have three transmembrane regions and several highly conserved ...
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.031587198
更新日期:2001-02-27 00:00:00
abstract::The signal-transducing guanine nucleotide-binding regulatory (G) proteins are heterotrimers composed of three subunits--alpha, beta, and gamma. Although multiple distinctive forms of the alpha subunit have been described, only two forms of the beta subunits of the G proteins have been identified. To investigate furthe...
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.87.6.2329
更新日期:1990-03-01 00:00:00
abstract::Commonly considered strategies for reducing the environmental impact of light-duty transportation include using alternative fuels and improving vehicle fuel economy. We evaluate the air quality-related human health impacts of 10 such options, including the use of liquid biofuels, diesel, and compressed natural gas (CN...
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.1406853111
更新日期:2014-12-30 00:00:00
abstract::Recent advances in our understanding of the immune response are allowing for the logical design of new approaches to cancer immunization. One area of interest is the development of new immune adjuvants. Immunostimulatory oligodeoxynucleotides containing the CpG motif (CpG ODN) can induce production of a wide variety 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.94.20.10833
更新日期:1997-09-30 00:00:00
abstract::Type VI protein secretion system (T6SS) is important for bacterial competition through contact-dependent killing of competitors. T6SS delivers effectors to neighboring cells and corresponding antagonistic proteins confer immunity against effectors that are delivered by sister cells. Although T6SS has been found in mor...
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.1222783110
更新日期:2013-02-12 00:00:00
abstract::The dnaZX gene of Escherichia coli directs the synthesis of two proteins, DnaZ and DnaX. These products are confirmed as the gamma and tau subunits of DNA polymerase III because antibody to a synthetic peptide present in both the DnaZ and DnaX proteins reacts also with the gamma and tau subunits of holoenzyme. To char...
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.84.9.2713
更新日期:1987-05-01 00:00:00
abstract::Thioredoxin (Trx) is an intracellular redox protein with extracellular cytokine-like and chemokine-like activities. We show here that, although plasma Trx levels are unrelated to survival of HIV-infected individuals with CD4 cell counts above 200/microl blood, survival is significantly impaired (P = 0.003) when plasma...
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.041624998
更新日期:2001-02-27 00:00:00