Abstract:
:We studied the effects of carbon starvation and of varying the growth rate on the activity of each of the two tandem ribosomal RNA promoters from the rrnA operon of Escherichia coli. The cellular abundance of plasmid-encoded transcripts arising at promoters P1 and P2 and terminating at the ribosomal RNA terminator in promoter-terminator fusions, together with transcript turnover rates, was used to estimate promoter activities. The rate of synthesis of the P1-promoted transcript was found to increase exponentially with growth rate and predominate at fast growth rates. The activity of the downstream promoter (P2) changed only slightly at different growth rates. Upon carbon starvation, little or no activity of the upstream promoter was detectable, while P2 activity persisted. We interpret this to mean that the dual promoters are differentially regulated so as to have separate adaptive and maintenance functions. This model simplifies most features of rRNA regulation known in E. coli.
journal_name
Proc Natl Acad Sci U S Aauthors
Sarmientos P,Cashel Mdoi
10.1073/pnas.80.22.7010subject
Has Abstractpub_date
1983-11-01 00:00:00pages
7010-3issue
22eissn
0027-8424issn
1091-6490journal_volume
80pub_type
杂志文章abstract::Nociceptive information is modulated by a large number of endogenous signaling agents that change over the course of recovery from injury. This plasticity makes understanding regulatory mechanisms involved in descending inhibition of pain scientifically and clinically important. Neurons that synthesize the neuropeptid...
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.1306342110
更新日期:2013-08-06 00:00:00
abstract::Recent reports on the dystrophic mouse mutant suggest that the prominent extracellular matrix component of peripheral nerve tissues plays an important role in peripheral nerve development. We have examined the disposition of two prominent extracellular matrix components, fibronectin and laminin, both in mature periphe...
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.80.12.3850
更新日期:1983-06-01 00:00:00
abstract::MinD is a widely conserved ATPase that has been demonstrated to play a pivotal role in selection of the division site in eubacteria and chloroplasts. It is a member of the large ParA superfamily of ATPases that are characterized by a deviant Walker-type ATP-binding motif. MinD localizes to the cytoplasmic face 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.232590599
更新日期:2002-11-26 00:00:00
abstract::Toll-like receptors (TLRs) are expressed on innate immune cells and trigger inflammation upon detection of pathogens and host tissue injury. TLR-mediated proinflammatory-signaling pathways are counteracted by partially characterized anti-inflammatory mechanisms that prevent exaggerated inflammation and host tissue dam...
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.1106232108
更新日期:2011-11-01 00:00:00
abstract::To gain further insight into the mode of action of S-locus receptor kinase (SRK), a receptor-like kinase involved in the self-incompatibility response in Brassica, different recombinant SRK proteins have been expressed in a membranous environment using the insect cell/baculovirus system. Recombinant SRK proteins exhib...
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.070025097
更新日期:2000-03-28 00:00:00
abstract::Using previously isolated Bacillus brevis strains that secrete large amounts of proteins but little protease into the medium, we have developed a host-vector system for very efficient synthesis and secretion of heterologous proteins. The multiple promoters and the signal-peptide-coding region of the MWP gene, a struct...
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.86.10.3589
更新日期:1989-05-01 00:00:00
abstract::Two endocytic receptors, the low density lipoprotein (LDL) receptor (LDLR) and the LDLR-related protein (LRP), are thought to act in concert in the hepatic uptake of partially metabolized dietary lipoproteins, the chylomicron remnants. We have evaluated the role of these two receptors in the hepatic metabolism of chyl...
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.92.10.4611
更新日期:1995-05-09 00:00:00
abstract::The expression and integration of membrane proteins into vesicle membranes is a critical step in the design of cell-mimetic biosensors, bioreactors, and artificial cells. While membrane proteins have been integrated into a variety of nonnatural membranes, the effects of the chemical and physical properties of these ve...
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.1814775116
更新日期:2019-03-05 00:00:00
abstract::Once-abundant aerial insectivores, such as the Tree Swallow (Tachycineta bicolor), have declined steadily in the past several decades, making it imperative to understand all aspects of their ecology. Aerial insectivores forage on a mixture of aquatic and terrestrial insects that differ in fatty acid composition, speci...
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.1603998113
更新日期:2016-09-27 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.69.7.1825
更新日期:1972-07-01 00:00:00
abstract::Tetherin/BST2 is a type-II membrane protein that inhibits the release of a range of enveloped viruses, including HIV-1. Here we report three crystal structures of human tetherin, including the full-length ectodomain, a triple cysteine mutant and an ectodomain truncation. These structures show that tetherin forms a con...
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.1011485107
更新日期:2010-10-26 00:00:00
abstract::Nanobacteria-like objects evidenced at the surface of the orthopyroxenes of the Tataouine meteorite in South Tunisia have been studied by scanning and transmission electron microscopies. A method of micromanipulation has been developed to ensure that exactly the same objects were studied by both methods. We have shown...
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.0832464100
更新日期:2003-06-24 00:00:00
abstract::P450c17 is the single enzyme mediating both 17 alpha-hydroxylase (steroid 17 alpha-monooxygenase, EC 1.14.99.9) and 17,20 lyase activities in the synthesis of steroid hormones. It has been suggested that different P450c17 isozymes mediate these activities in the adrenal gland and testis. We sequenced 423 of the 509 am...
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.84.2.407
更新日期:1987-01-01 00:00:00
abstract::Circadian rhythms describe biological phenomena that oscillate with an approximately 24-hour cycle. These rhythms include blood pressure, body temperature, hormone levels, the number of immune cells in blood, and the sleep-wake cycle. In this paper, we will focus on common genes between species that are responsible fo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.96.16.8819
更新日期:1999-08-03 00:00:00
abstract::Bordetella pertussis secretes a calmodulin-activated adenylate cyclase toxin, CyaA, that is able to deliver its N-terminal catalytic domain (400-aa residues) into the cytosol of eukaryotic target cells, directly through the cytoplasmic membrane. We have previously shown that CyaA can be used as a vehicle to deliver 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.95.21.12532
更新日期:1998-10-13 00:00:00
abstract::Embryonic stem cells (ESCs) represent an important research tool and a potential resource for regenerative medicine. Generally, ESCs are cocultured with a supportive feeder cell layer of murine embryonic fibroblasts, which maintain the ESCs' capacity for self-renewal and block spontaneous differentiation. These cumber...
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.0701331104
更新日期:2007-03-27 00:00:00
abstract::Energetics of resting and evoked fMRI signals were related to localized ensemble firing rates (nu) measured by electrophysiology in rats. Two different unstimulated, or baseline, states were established by anesthesia. Halothane and alpha-chloralose established baseline states of high and low energy, respectively, in w...
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.0709515104
更新日期:2007-12-18 00:00:00
abstract::Cellular transformation by the BCR/ABL oncogene depends on the ABL-encoded tyrosine kinase activity. To block BCR/ABL function, we created a unique tyrosine phosphatase by fusing the catalytic domain of SHP1 (SHP1c) to the ABL binding domain (ABD) of RIN1, an established binding partner and substrate for c-ABL and BCR...
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.210253497
更新日期:2000-10-24 00:00:00
abstract::Memory CD4(+) T helper (Th) cells are central to long-term protection against pathogens, but they can also be pathogenic and drive chronic inflammatory disorders. How these pathogenic memory Th cells are maintained, particularly at sites of local inflammation, remains unclear. We found that ectopic lymphoid-like struc...
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.1512600113
更新日期:2016-05-17 00:00:00
abstract::The major virulence determinant of the rodent malaria parasite, Plasmodium yoelii, has remained unresolved since the discovery of the lethal line in the 1970s. Because virulence in this parasite correlates with the ability to invade different types of erythrocytes, we evaluated the potential role of the parasite eryth...
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.0811313106
更新日期:2009-04-28 00:00:00
abstract::Activation of androgen receptor (AR) via androgen in muscle cells has been closely linked to their growth and differentiation. Here, we report the cloning and characterization of supervillin (SV), a 205-kDa actin-binding protein, as an AR coregulator from the skeletal muscle cDNA library. Mammalian two-hybrid and glut...
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.022469899
更新日期:2002-01-22 00:00:00
abstract::Coatomer, the coat protein of coat protein complex (COP)I-vesicles, is a soluble protein complex made up of seven subunits, alpha-, beta-, beta'-, gamma-, delta-, epsilon-, and zeta-COP. Higher eukaryotes have two paralogous versions of the gamma- and zeta- subunits, termed gamma1- and gamma2-COP and zeta1- and zeta2-...
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.0611360104
更新日期:2007-03-13 00:00:00
abstract::Ring-shaped hexameric helicases and translocases support essential DNA-, RNA-, and protein-dependent transactions in all cells and many viruses. How such systems coordinate ATPase activity between multiple subunits to power conformational changes that drive the engagement and movement of client substrates is a fundame...
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.1616745113
更新日期:2016-11-29 00:00:00
abstract::IL-17 is a T cell-derived, proinflammatory cytokine that is suspected to be involved in the development of various inflammatory diseases. Although there are elevated levels of IL-17 in synovial fluid of patients with rheumatoid arthritis, the pathogenic role of IL-17 in the development of rheumatoid arthritis remains ...
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.1035999100
更新日期:2003-05-13 00:00:00
abstract::The mathematical theory of compressed sensing (CS) asserts that one can acquire signals from measurements whose rate is much lower than the total bandwidth. Whereas the CS theory is now well developed, challenges concerning hardware implementations of CS-based acquisition devices--especially in optics--have only start...
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.1119511109
更新日期:2012-06-26 00:00:00
abstract::The antigenic sites of horse and rat cytochromes c in the major antigenic region were compared using a panel of variant cytochromes c and a large number of BALB/c mouse monoclonal antibodies (mAbs) in competitive ELISAs. The major antigenic region of cytochrome c is located on the surface opposite of that containing 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.88.10.4428
更新日期:1991-05-15 00:00:00
abstract::Three proteins required for poly(U)-directed polyphenylalanine synthesis have been separated from yeast. Two of the factors correspond to the elongation factors 1 and 2 described for other eukaryotic systems, according to the criteria of phenylalanyl-tRNA binding and diphtheria toxin-catalyzed ADP-ribosylation. The th...
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.73.1.73
更新日期:1976-01-01 00:00:00
abstract::Many higher level avian clades are restricted to Earth's lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and numerous deep subclades. However, several such "tropical-restricted" clades (TRCs) are represented by stem-lineage fossils well outside the ranges...
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.1903866116
更新日期:2019-06-25 00:00:00
abstract::Previous studies in Saccharomyces cerevisiae have defined an essential role for the Dbf4-Cdc7 kinase complex in the initiation of DNA replication presumably by phosphorylation of target proteins, such as the minichromosome maintenance (Mcm) complex. We have examined the phosphorylation of the Mcm complex by the Dfp1-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.0237384100
更新日期:2003-03-04 00:00:00
abstract::8-L-Arginine vasopressin ([Arg8]VP) receptors are expressed transiently in the rat facial nucleus during the perinatal period. Electrophysiological studies suggest that at least part of these receptors is located on facial motoneurones. In the present study we report that, in the adult rat, unilateral section of a fac...
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.91.20.9636
更新日期:1994-09-27 00:00:00