Abstract:
:Mutants of Escherichia coli sensitive to phage T4 gene 2 mutants were obtained following ethyl methanesulfonate mutagenesis. By mapping and complementation analysis, the mutations in each of the six mutants are in recB and recC. By both in vivo and in vitro analyses, the nuclease activity of RecBC enzyme is undetectable in these mutants. However, by several other criteria, such as proficiency in recombination, relative resistance to UV radiation, and viability of the cells in the culture, these mutants are almost identical to their recBC+ parent. The properties of these mutants indicate that the ATP-dependent double-stranded DNA exonuclease activity of RecBC enzyme is not required for recombination. Chi recombinational hotspots, which stimulate recombination by the RecBC pathway, have no detectable activity in the mutants. This result suggests that the nuclease activity of RecBC enzyme is required for Chi activity and is consistent with the hypothesis that Chi stimulates recombination by directing RecBC enzyme to cut DNA at or near Chi.
journal_name
Proc Natl Acad Sci U S Aauthors
Chaudhury AM,Smith GRdoi
10.1073/pnas.81.24.7850subject
Has Abstractpub_date
1984-12-01 00:00:00pages
7850-4issue
24eissn
0027-8424issn
1091-6490journal_volume
81pub_type
杂志文章abstract::Phagocytosis is a primary defense program orchestrated by monocytes/macrophages. Unregulated phagocytosis can lead to pathological conditions. In the current study we have demonstrated that Wnt5a stimulates phagocytosis through PI3 kinase-Rac1 and lipid-raft-dependent processes. Wnt5a-mediated augmentation in phagocyt...
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.1207789109
更新日期:2012-10-09 00:00:00
abstract::Selective inhibition of the intrinsic coagulation pathway is a promising strategy for developing safer anticoagulants that do not cause serious bleeding. Intrinsic tenase, the final and rate-limiting enzyme complex in the intrinsic coagulation pathway, is an attractive but less explored target for anticoagulants due 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.1504229112
更新日期:2015-07-07 00:00:00
abstract::Insulin provides a classical model of a globular protein, yet how the hormone changes conformation to engage its receptor has long been enigmatic. Interest has focused on the C-terminal B-chain segment, critical for protective self-assembly in β cells and receptor binding at target tissues. Insight may be obtained fro...
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.1412897111
更新日期:2014-08-19 00:00:00
abstract::Urbanization and rural-urban migration are two factors driving global patterns of disease and mortality. There is significant concern about their potential impact on disease burden and the effectiveness of current control approaches. Few attempts have been made to increase our understanding of the relationship between...
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.1712767115
更新日期:2018-05-01 00:00:00
abstract::The conserved Ndc80 complex is an essential microtubule-binding component of the kinetochore. Recent findings suggest that the Ndc80 complex influences microtubule dynamics at kinetochores in vivo. However, it was unclear if the Ndc80 complex mediates these effects directly, or by affecting other factors localized at ...
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.1209615109
更新日期:2012-10-02 00:00:00
abstract::We found that two markers of differentiation, tyrosinase (monophenol, dihydroxyphenylalanine:oxygen oxidoreductase, EC 1.14.18.1) activity and melanin synthesis, are induced by diazepam in B16/C3 mouse melanoma cells. We also demonstrated high-affinity binding sites for [3H]diazepam in these cells by radioreceptor ass...
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.78.6.3935
更新日期:1981-06-01 00:00:00
abstract::Many native proteins occasionally form partially unfolded forms (PUFs), which can be detected by hydrogen/deuterium exchange and NMR spectroscopy. Knowledge about these metastable states is required to better understand the onset of folding-related diseases. So far, not much is known about where PUFs reside within 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.0509133103
更新日期:2006-03-14 00:00:00
abstract::Mitochondrial cytochrome c oxidase plays an essential role in aerobic cellular respiration, reducing dioxygen to water in a process coupled with the pumping of protons across the mitochondrial inner membrane. An aspartate residue, Asp-51, located near the enzyme surface, undergoes a redox-coupled x-ray structural chan...
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.2635097100
更新日期:2003-12-23 00:00:00
abstract::Mutations in genes encoding membrane proteins have been associated with cell death of unknown cause from invertebrate development to human degenerative diseases. A point mutation in the gene for myelin proteolipid protein (PLP) underlies oligodendrocyte death and dysmyelination in jimpy mice, an accurate model for Pel...
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.92.10.4447
更新日期:1995-05-09 00:00:00
abstract::Natural killer (NK) cells recognize alloantigens on normal cells. One of these alloantigens correlates with homozygosity for a dimorphism of HLA-C at positions 77-80, which is shared by a number of HLA-C alleles. A second allelic alloantigen correlates with homozygosity for the alternative HLA-C dimorphism, which is 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.90.24.12000
更新日期:1993-12-15 00:00:00
abstract::Vertebrate primary cilium is a Hedgehog signaling center but the extent of its involvement in other signaling systems is less well understood. This report delineates a mechanism by which fibroblast growth factor (FGF) controls primary cilia. Employing proteomic approaches to characterize proteins associated with the F...
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.1800338116
更新日期:2019-03-05 00:00:00
abstract::RNAs 1 and 2 of the tripartite cowpea chlorotic mottle virus (CCMV) genome are sufficient for RNA replication in protoplasts, whereas systemic infection of cowpea plants additionally requires RNA3, which encodes the 3a noncapsid protein and coat protein. By using biologically active CCMV cDNA clones, we find that dele...
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.87.5.1820
更新日期:1990-03-01 00:00:00
abstract::Bacteriophage Mu was inserted into the unc genes of Escherichia coli. The resulting mutation AS12 had a polar effect on the unc operon: membranes of the mutant AS12 contained the dicyclohexylcarbodiimide-binding protein c and the protein a as sole subunits of the ATP synthase. It was shown by peptide mapping and amino...
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.78.11.6643
更新日期:1981-11-01 00:00:00
abstract::The catalytic cysteine of the typical 2-Cys Prx subfamily of peroxiredoxins is occasionally hyperoxidized to cysteine sulfinic acid during the peroxidase catalytic cycle. Sulfinic Prx (Prx-SO2H) is reduced back to the active form of the enzyme by sulfiredoxin. The abundance of Prx-SO2H was recently shown to oscillate ...
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.1401100111
更新日期:2014-08-19 00:00:00
abstract::In both human patients and murine models, the progression from insulitis to diabetes is neither immediate nor inevitable, as illustrated by the innocuous versus destructive infiltrates of BDC2.5 transgenic mice on the nonobese diabetic (NOD) versus C57BL/6.H-2g7 genetic backgrounds. Natural killer (NK)-cell-specific 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.0402065101
更新日期:2004-05-25 00:00:00
abstract::Ancient societies are often used to illustrate the potential problems stemming from unsustainable land-use practices because the past seems rife with examples of sociopolitical "collapse" associated with the exhaustion of finite resources. Just as frequently, and typically in response to such presentations, archaeolog...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
doi:10.1073/pnas.1409646111
更新日期:2014-08-12 00:00:00
abstract::Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic e...
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.1204237109
更新日期:2012-08-14 00:00:00
abstract::Like all aliphatic amines, the polyamines spermine and spermidine are physical quenchers of singlet molecular oxygen (1O2*). The rate constants of these processes were determined in vitro with photochemically generated 1O2* and the hydrocarbon rubrene as substrate, in pyridine. At millimolar concentration, spermine an...
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.89.23.11426
更新日期:1992-12-01 00:00:00
abstract::The integrase protein of human immunodeficiency virus type 1 is necessary for the stable integration of the viral genome into host DNA. Integrase catalyzes the 3' processing of the linear viral DNA and the subsequent DNA strand transfer reaction that inserts the viral DNA ends into host DNA. Although full-length integ...
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.92.13.6057
更新日期:1995-06-20 00:00:00
abstract::Genetic potentials (pedigree-estimated breeding value) for milk and for fat were compared in cows grouped according to subclinical stage of bovine leukemia virus infection. Genetic potential for milk production was significantly greater in seropositive cows with persistent lymphocytosis (622 +/- 72 kg) and in seroposi...
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.86.3.993
更新日期:1989-02-01 00:00:00
abstract::Vascular endothelial cells (ECs) at arterial branches and curvatures experience disturbed blood flow and induce a quiescent-to-activated phenotypic transition of the adjacent smooth muscle cells (SMCs) and a subsequent smooth muscle hyperplasia. However, the mechanism underlying the flow pattern-specific initiation of...
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.1700561114
更新日期:2017-08-01 00:00:00
abstract::The RNA virus, hepatitis E virus (HEV) is the most or second-most important cause of acute clinical hepatitis in adults throughout much of Asia, the Middle East, and Africa. In these regions it is an important cause of acute liver failure, especially in pregnant women who have a mortality rate of 20-30%. Until recentl...
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.1018878108
更新日期:2011-02-08 00:00:00
abstract::In a posterior silk gland extract, covalently closed circular (ccc) DNA is in a superhelical state that supports more transcription of fibroin gene than does linear DNA. A HeLa cell extract showed neither the supercoiling activity nor the preference for the transcription of ccc DNA over linear DNA. These activities co...
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.85.3.718
更新日期:1988-02-01 00:00:00
abstract::Ouabain-sensitive uncoupled Na+ efflux has been studied in human, pig, and rat red cells and in vesicles containing reconstituted kidney Na+/K+ pumps obtained from these same species. The red cells from the different species gave qualitatively similar results; the uncoupled Na+ efflux was 15-30% of the Na+/K+ exchange...
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.91.21.9881
更新日期:1994-10-11 00:00:00
abstract::Lakes are considered the second largest natural source of atmospheric methane (CH4). However, current estimates are still uncertain and do not account for diel variability of CH4 emissions. In this study, we performed high-resolution measurements of CH4 flux from several lakes, using an automated and sensor-based flux...
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.2006024117
更新日期:2020-09-01 00:00:00
abstract::Deleting an important active-site residue of diphtheria toxin, glutamic acid-148, reduces the toxin's ADP-ribosyltransferase activity by a factor of greater than 10(4). We considered using this mutation to construct a recombinant toxoid for expression by live attenuated vaccines and explored second-site mutations 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.89.13.6207
更新日期:1992-07-01 00:00:00
abstract::The Late Quaternary glacial-interglacial transitions represent the highest amplitude climate changes over the last million years. Unraveling the sequence of events and feedbacks at Termination III (T-III), including potential abrupt climate reversals similar to those of the last Termination, has been particularly chal...
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.1619615114
更新日期:2017-09-19 00:00:00
abstract::The regulatory mechanisms underlying the uptake and utilization of multiple types of carbohydrates in actinomycetes remain poorly understood. In this study, we show that GlnR (central regulator of nitrogen metabolism) serves as a universal regulator of nitrogen metabolism and plays an important, previously unknown rol...
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.1508465112
更新日期:2015-12-22 00:00:00
abstract::The switch from fetal to adult hemoglobin expression is regulated in many mammalian species by a developmental clock-like mechanism and determined by the gestational age of the fetus. Prolonging fetal globin gene expression is of considerable interest for therapeutic potential in diseases caused by abnormal beta-globi...
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.85.22.8540
更新日期:1988-11-01 00:00:00
abstract::Human IL-10 (hIL-10) modulates critical immune and inflammatory responses by way of interactions with its high- (IL-10R1) and low-affinity (IL-10R2) cell surface receptors. Human cytomegalovirus exploits the IL-10 signaling pathway by expressing a functional viral IL-10 homolog (cmvIL-10), which shares only 27% sequen...
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.152147499
更新日期:2002-07-09 00:00:00