Abstract:
:Using a HeLa cell line stably transfected with the tat gene from human immunodeficiency virus type 1, we have found that the expression of the regulatory Tat protein suppresses the expression of cellular Mn-containing superoxide dismutase (Mn-SOD). This enzyme is one of the cell's primary defenses against oxygen-derived free radicals and is vital for maintaining a healthy balance between oxidants and antioxidants. The parental HeLa cells expressed nearly equivalent amounts of Cu,Zn- and Mn-SOD isozymes. Those cells expressing the Tat protein, however, contained 52% less Mn-SOD activity than parental cells, whereas that of the Cu,Zn enzyme was essentially unchanged. The steady-state levels of Mn-SOD-specific RNAs were also lower in the HeLa-tat cell line than in the parental line. No difference was seen in the steady-state levels of Cu,Zn-SOD-specific RNAs. In addition to the decreased Mn-SOD-activity, HeLa-tat cell showed evidence of increased oxidative stress. Carbonyl proteins were markedly higher, and total cellular sulfhydryl content decreased in cell extracts at a faster rate, probably reflecting ongoing lipid peroxidation. HeLa and HeLa-tat extracts were incubated with radiolabeled Mn-SOD transcripts, and the reaction products were subjected to UV crosslinking, digestion with ribonuclease A, and electrophoretic analysis. The results suggest a direct interaction between Tat protein and Mn-SOD gene transcripts.
journal_name
Proc Natl Acad Sci U S Aauthors
Flores SC,Marecki JC,Harper KP,Bose SK,Nelson SK,McCord JMdoi
10.1073/pnas.90.16.7632subject
Has Abstractpub_date
1993-08-15 00:00:00pages
7632-6issue
16eissn
0027-8424issn
1091-6490journal_volume
90pub_type
杂志文章abstract::The Hsp90 chaperone buffers development against a wide range of morphological changes in many organisms and in Drosophila masks the effects of hidden genetic variation. Theory predicts that genetic and nongenetic buffering will share common mechanisms. For example, it is argued that Hsp90 genetic buffering evolved sol...
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.1835613100
更新日期:2003-11-11 00:00:00
abstract::Proteins synthesized in the cell can begin to fold during translation before the entire polypeptide has been produced, which may be particularly relevant to the folding of multidomain proteins. Here, we study the cotranslational folding of adjacent domains from the cytoskeletal protein α-spectrin using force profile 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.1909683117
更新日期:2020-06-23 00:00:00
abstract::The androgen receptor (AR) plays an essential role in prostate cancer, and suppression of its signaling with androgen deprivation therapy (ADT) has been the mainstay of treatment for metastatic hormone-sensitive prostate cancer for more than 70 y. Chemotherapy has been reserved for metastatic castration-resistant pros...
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.1600420113
更新日期:2016-05-31 00:00:00
abstract::The formation of myelin by Schwann cells (SCs) occurs via a series of orchestrated molecular events. We previously used global expression profiling to examine peripheral nerve myelination and identified the NAD(+)-dependent deacetylase Sir-two-homolog 2 (Sirt2) as a protein likely to be involved in myelination. 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.1104969108
更新日期:2011-10-25 00:00:00
abstract::Monoclonal antibodies against the porcine 1,25-dihydroxyvitamin D3 receptor were immobilized on Sepharose CL-4B and used to obtain a highly purified 1,25-dihydroxyvitamin D3 receptor fraction with a 45% recovery of the 1,25-dihydroxyvitamin D3 binding capacity. The porcine receptor was purified to homogeneity by prepa...
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.85.8.2454
更新日期:1988-04-01 00:00:00
abstract::We introduce a new genetic distance for microsatellite loci, incorporating features of the stepwise mutation model, and test its performance on microsatellite polymorphisms in humans, chimpanzees, and gorillas. We find that it performs well in determining the relations among the primates, but less well than other dist...
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.92.15.6723
更新日期:1995-07-18 00:00:00
abstract::A protein factor that participates in the formation of a covalent complex between the 80,000-dalton precursor of the adenovirus (Ad) terminal protein (pTP) and 5'-dCMP has been isolated and characterized. This 47,000-dalton protein, isolated from nuclear extracts of uninfected HeLa cells, has been designated nuclear 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.79.21.6438
更新日期:1982-11-01 00:00:00
abstract::We propose that retroviruses exploit a cell-encoded pathway of intercellular vesicle traffic, exosome exchange, for both the biogenesis of retroviral particles and a low-efficiency but mechanistically important mode of infection. This Trojan exosome hypothesis reconciles current paradigms of retrovirus-directed transm...
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.1831413100
更新日期:2003-09-16 00:00:00
abstract::The Arabidopsis thaliana SOS2 and SOS3 genes are required for intracellular Na(+) and K(+) homeostasis and plant tolerance to high Na(+) and low K(+) environments. SOS3 is an EF hand type calcium-binding protein having sequence similarities with animal neuronal calcium sensors and the yeast calcineurin B. SOS2 is a se...
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.040577697
更新日期:2000-03-28 00:00:00
abstract::Mycoplasmas require an external source of sterol for growth. For Mycoplasma capricolum this requirement is met not only by cholesterol but also by the methylcholestane derivatives lanosterol, cycloartenol, 4,4-dimethylcholesterol, and 4beta-methylcholestanol. Cholesteryl methyl ether and 3alpha-methylcholestanol serve...
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.75.9.4107
更新日期:1978-09-01 00:00:00
abstract::Antibodies that modulate receptor function have great untapped potential in the control of stem cell differentiation. In contrast to many natural ligands, antibodies are stable, exquisitely specific, and are unaffected by the regulatory mechanisms that act on natural ligands. Here we describe an innovative system 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.1312062110
更新日期:2013-10-29 00:00:00
abstract::Osmotically shocked Escherichia coli and membrane vesicle ghosts from E. coli cells have lost the ability to accumulate potassium by active transport. The addition of valinomycin to the membrane ghosts restores the capacity to accumulate radioactive (42)K and (86)Rb by a temperature- and energy-dependent process. Memb...
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.68.7.1488
更新日期:1971-07-01 00:00:00
abstract::High-resolution analyses of a late Holocene core from Kettle Lake in North Dakota reveal coeval fluctuations in loss-on-ignition carbonate content, percentage of grass pollen, and charcoal flux. These oscillations are indicative of climate-fuel-fire cycles that have prevailed on the Northern Great Plains (NGP) for mos...
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.0503621102
更新日期:2005-06-21 00:00:00
abstract::Impaired magnesium reabsorption in patients with TRPM6 gene mutations stresses an important role of TRPM6 (melastatin-related TRP cation channel) in epithelial magnesium transport. While attempting to isolate full-length TRPM6, we found that the human TRPM6 gene encodes multiple mRNA isoforms. Full-length TRPM6 varian...
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.0305252101
更新日期:2004-03-02 00:00:00
abstract::A cell line has been developed from the imaginal wing discs of the lepidopteran insect Trichoplusia ni (Hübner). The cells grow in suspension as fluid-filled, multicellular vesicles. The cell line has been designated IAL-TND1. Two-dimensional electrophoresis (isoelectric focusing and sodium dodecyl sulfate/polyacrylam...
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.79.8.2589
更新日期:1982-04-01 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::G protein-coupled receptors (GPCRs) are seven-transmembrane proteins that transmit diverse extracellular signals across a membrane. Herpesvirus genomes encode multiple GPCRs implicated in viral pathogenesis. Kaposi sarcoma-associated herpesvirus GPCR (kGPCR) activates proliferative pathways and, when expressed in endo...
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.1219829110
更新日期:2013-07-02 00:00:00
abstract::We investigate energy transport through an alpha-aminoisobutyric acid-based 3(10)-helix dissolved in chloroform in a combined experimental-theoretical approach. Vibrational energy is locally deposited at the N terminus of the helix by ultrafast internal conversion of a covalently attached, electronically excited, azob...
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.0701762104
更新日期:2007-07-31 00:00:00
abstract::Effects of previous strength training can be long-lived, even after prolonged subsequent inactivity, and retraining is facilitated by a previous training episode. Traditionally, such "muscle memory" has been attributed to neural factors in the absence of any identified local memory mechanism in the muscle tissue. We h...
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.0913935107
更新日期:2010-08-24 00:00:00
abstract::The final step in hydrocarbon biosynthesis involves loss of CO from a fatty aldehyde. This decarbonylation is catalyzed by microsomes from Botyrococcus braunii. Among the several detergents tested for solubilizing the decarbonylase, octyl beta-glucoside (0.1%) was found to be the most effective and released 65% of 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.89.12.5306
更新日期:1992-06-15 00:00:00
abstract::Among yeasts that underwent whole-genome duplication (WGD), Kluyveromyces polysporus represents the lineage most distant from Saccharomyces cerevisiae. By sequencing the K. polysporus genome and comparing it with the S. cerevisiae genome using a likelihood model of gene loss, we show that these species diverged very 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.0608218104
更新日期:2007-05-15 00:00:00
abstract::Genome editing with engineered site-specific endonucleases involves nonhomologous end-joining, leading to reading frame disruption. The approach is applicable to dominant negative disorders, which can be treated simply by knocking out the mutant allele, while leaving the normal allele intact. We applied this strategy ...
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.1512028113
更新日期:2016-05-17 00:00:00
abstract::Duplication of the genome during the S phase of the cell cycle does not occur simultaneously; rather, different sequences are replicated at different times. The replication timing of specific sequences can change during development; however, the determinants of this dynamic process are poorly understood. To gain insig...
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.0408170101
更新日期:2004-12-21 00:00:00
abstract::We present here a shorter version of the proof of our earlier work, showing that the von Neumann factor associated with the group Z(2)SL(2,Z) has trivial fundamental group. ...
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.2333960100
更新日期:2004-01-20 00:00:00
abstract::Signaling lymphocytic activation molecule family 3 (SLAMF3/Ly9) is a coregulatory molecule implicated in T-cell activation and differentiation. Systemic lupus erythematosus (SLE) is characterized by aberrant T-cell activation and compromised IL-2 production, leading to abnormal regulatory T-cell (Treg) development/fun...
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.1605081113
更新日期:2016-08-16 00:00:00
abstract::The 33-amino-acid ankyrin motif comprises a beta-turn followed by two anti-parallel alpha-helices and a loop and tandem arrays of the motif pack in a linear fashion to produce elongated structures characterized by short-range interactions. In this article we use site-directed mutagenesis to investigate the kinetic unf...
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.0705300105
更新日期:2008-07-22 00:00:00
abstract::Because many survivors of mass extinctions do not participate in postrecovery diversifications, and therefore fall into a pattern that can be termed "Dead Clade Walking" (DCW), the effects of mass extinctions extend beyond the losses observed during the event itself. Analyses at two taxonomic levels provide a first-or...
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.102163299
更新日期:2002-06-11 00:00:00
abstract::Ventriculo-cisternal perfusion of horseradish peroxidase (HRP) in the mouse brain has demonstrated that a brain-blood barrier exists at the microvascular endothelium in brain parenchyma but not in the median eminence of the hypothalamus. The brain-blood barrier is similar to the blood-brain barrier in that: tight junc...
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.80.23.7352
更新日期:1983-12-01 00:00:00
abstract::Our recent demonstration that many eukaryotic mRNAs contain sequences complementary to rRNA led to the hypothesis that these sequences might mediate specific interactions between mRNAs and ribosomes and thereby affect translation. In the present experiments, the ability of complementary sequences to bind to rRNA was i...
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.95.21.12238
更新日期:1998-10-13 00:00:00
abstract::Particles composed of secondary organic material (SOM) are abundant in the lower troposphere. The viscosity of these particles is a fundamental property that is presently poorly quantified yet required for accurate modeling of their formation, growth, evaporation, and environmental impacts. Using two unique techniques...
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.1219548110
更新日期:2013-05-14 00:00:00