Abstract:
:The araCBAD regulatory region of Escherichia coli contains two divergently oriented promoters and three sites to which AraC, the regulatory protein of the operon, can bind. This paper presents the results of in vivo dimethyl sulfate "footprinting" experiments to monitor occupancy of the three AraC sites and measurements of activity of the two promoters. These measurements were made both in the absence of the inducer arabinose and at various times after arabinose addition to growing cells containing the wild-type ara regulatory region or the regulatory region containing various deletions and point mutations. The data lead to the conclusion that two different DNA loops can form in the ara regulatory region. These loops are generated by AraC protein molecules binding to two different DNA sites and binding to each other. One of these loops predominates in the absence of arabinose and plays a major role in repressing activity of one of the promoters. Upon the addition of arabinose the amount of the first loop type, the repression loop, decreases and the amount of a second loop increases. Formation of this second loop precludes the counterproductive formation of the repression loop.
journal_name
Proc Natl Acad Sci U S Aauthors
Huo L,Martin KJ,Schleif Rdoi
10.1073/pnas.85.15.5444subject
Has Abstractpub_date
1988-08-01 00:00:00pages
5444-8issue
15eissn
0027-8424issn
1091-6490journal_volume
85pub_type
杂志文章abstract::Three lines of evidence indicate that RNA-dependent RNA synthesis occurs in mouse erythroleukemia cells. The first involves labeling studies with [3H]uridine and shows a greater initial labeling rate of globin RNA in the cytoplasm than in the nucleus. Labeled globin RNA found in the cytoplasm after a very short pulse ...
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.83.5.1208
更新日期:1986-03-01 00:00:00
abstract::The basolateral membranes of Aplysia californica foregut absorptive cells contain both Cl(-)-stimulated ATPase and ATP-dependent Cl- transport activities, and each was inhibited by orthovanadate. Both of these orthovanadate-sensitive activities were reconstituted into proteoliposomes. The reaction sequence kinetics we...
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.90.17.7970
更新日期:1993-09-01 00:00:00
abstract::Three-dimensional microfluidic systems were fabricated and used to pattern proteins and mammalian cells on a planar substrate. The three-dimensional topology of the microfluidic network in the stamp makes this technique a versatile one with which to pattern multiple types of proteins and cells in complex, discontinuou...
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.040562297
更新日期:2000-03-14 00:00:00
abstract::Ultrastructural immunocytochemical studies of the expression of major histocompatibility complex class I antigens in the placentas of inbred rats were performed using placentas derived from natural matings and from embryo transfers into females made pseudopregnant by mechanical stimulation. The studies utilized the WF...
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.87.1.444
更新日期:1990-01-01 00:00:00
abstract::Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent endogenous activator of the cell death pathway and functions by activating the cell surface death receptors 4 and 5 (DR4 and DR5). TRAIL is nontoxic in vivo and preferentially kills neoplastically transformed cells over normal cells by an unde...
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.030545097
更新日期:2000-02-15 00:00:00
abstract::Urodeles and fetal mammals are capable of impressive epimorphic regeneration in a variety of tissues, whereas the typical default response to injury in adult mammals consists of inflammation and scar tissue formation. One component of epimorphic regeneration is the recruitment of resident progenitor and stem cells to ...
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.0905851106
更新日期:2010-02-23 00:00:00
abstract::Endothelin 1 causes a strong Ca2+ signal in C6 rat glioma cells as measured by fura-2 fluorescence. This endothelin 1-induced Ca2+ signal was not observed when the cells were persistently infected with a measles virus strain of subacute sclerosing panencephalitis (SSPE, strain Lec). Binding of 125I-labeled endothelin ...
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.88.15.6736
更新日期:1991-08-01 00:00:00
abstract::Purine nucleoside analogs modified by replacement of the nitrogen atom at the 3 position by a CH group give a characteristic circular dichroism curve that is not substantially modified by chemical substitution at the 8 position. Since it is rather well established that 8-substituted purine nucleosides are predominantl...
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.73.7.2384
更新日期:1976-07-01 00:00:00
abstract::We obtain a general connection between a large quantum advantage in communication complexity and Bell nonlocality. We show that given any protocol offering a sufficiently large quantum advantage in communication complexity, there exists a way of obtaining measurement statistics that violate some Bell inequality. Our m...
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.1507647113
更新日期:2016-03-22 00:00:00
abstract::Two precursors to Chinook salmon (Oncorhynchus tshawytscha) melanin-concentrating hormone, an important factor in teleosts involved in the control of skin pigmentation and stress responsiveness, have been identified from DNA sequence analysis. Both precursors encode proteins of 132 amino acids and they share 107/132 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.86.11.4292
更新日期:1989-06-01 00:00:00
abstract::Proteins of plant cell walls serve as structural macromolecules and play important roles in morphogenesis and development but have not been reported to be the origins of peptide signals that activate genes for plant defense. We report here that the mRNA coding the tomato leaf polyprotein precursor of three hydroxyprol...
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.0505248102
更新日期:2005-09-06 00:00:00
abstract::Neuroglobin (Ngb), a vertebrate globin expressed primarily in neurons, is induced by and protects against neuronal hypoxia and cerebral ischemia. To investigate the spectrum and mechanism of Ngb's neuroprotective action, we studied the effect of transgenic overexpression of Ngb on NMDA and beta-amyloid (Abeta) toxicit...
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.0706167104
更新日期:2007-11-27 00:00:00
abstract::Human tyrosyl-DNA phosphodiesterase (TDP1) hydrolyzes the phosphodiester bond at a DNA 3'-end linked to a tyrosyl moiety and has been implicated in the repair of topoisomerase I (Top1)-DNA covalent complexes. TDP1 can also hydrolyze other 3'-end DNA alterations including 3'-phosphoglycolate and 3'-abasic sites, and ex...
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.1009814107
更新日期:2010-11-16 00:00:00
abstract::Integration sites for many retrotransposons and retroviruses are determined by interactions between retroelement-encoded integrases and specific DNA-bound proteins. The Saccharomyces retrotransposon Ty5 preferentially integrates into heterochromatin because of interactions between Ty5 integrase and the heterochromatin...
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.1103665108
更新日期:2011-12-20 00:00:00
abstract::Peptide nucleic acid (PNA) is a DNA mimic that has shown considerable promise as a lead compound for developing gene therapeutic drugs. We report that PNAs targeted to functional and accessible sites in ribosomal RNA can inhibit translation in an Escherichia coli cell-free transcription/translation system, with 50% 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.95.5.2073
更新日期:1998-03-03 00:00:00
abstract::Binding of a partial proteolytic digest by V8 enzyme of the yeast site-specific recombinase Flp to its target site gives rise to DNA-protein complexes that are smaller than those produced by the full-sized protein. The smallest of these complexes (occupancy of one peptide monomer per site) contains either one of two 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.88.14.5944
更新日期:1991-07-15 00:00:00
abstract::An effective plant alkaloid chemical defense requires a variety of transport processes, but few alkaloid transporters have been characterized at the molecular level. Previously, a gene fragment encoding a putative plasma membrane proton symporter was isolated, because it was coordinately regulated with several nicotin...
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.1108620108
更新日期:2011-11-01 00:00:00
abstract::We present a simple theory that uses thermodynamic parameters to predict the probability that a protein retains the wild-type structure after one or more random amino acid substitutions. Our theory predicts that for large numbers of substitutions the probability that a protein retains its structure will decline expone...
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.0406744102
更新日期:2005-01-18 00:00:00
abstract::Members of the platelet-derived growth factor (PDGF) ligand family are known to play important roles in wound healing and fibrotic disease. We show that both transient and stable expression of PDGF-C results in the development of liver fibrosis consisting of the deposition of collagen in a pericellular and perivenular...
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.0409722102
更新日期:2005-03-01 00:00:00
abstract::TAL1 is a critical transcription factor required for hematopoiesis. However, perturbation of its activity often leads to T cell leukemia. Whether and how its transcriptional activities are regulated during hematopoiesis remains to be addressed. Here, we show that TAL1 is associated with histone demethylase complexes c...
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.0900437106
更新日期:2009-06-23 00:00:00
abstract::Invasive potentials of carcinomas greatly contribute to their metastasis, which is a major threat in most cancers. We have recently shown that Arf6 plays a pivotal role in breast cancer invasive activities and identified AMAP1 as an effector of GTP-Arf6 in invasion. Expression of AMAP1 correlates well with invasive ph...
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.0509166103
更新日期:2006-05-02 00:00:00
abstract::The amino-acid sequence of the gamma-carboxyglutamic acid-containing protein of bovine bone is presented. The sequence of 43 of the 49 residues was determined automatically on the intact protein and on a tryptic peptide. The remainder was determined by conventional procedures on tryptic and chymotrytic peptides. Resid...
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.73.10.3374
更新日期:1976-10-01 00:00:00
abstract::Ovulation induces cyclic rupture and regenerative repair of the ovarian coelomic epithelium. This process of repeated disruption and repair accompanied by complex remodeling typifies a somatic stem/progenitor cell-mediated process. Using BrdU incorporation and doxycycline inducible histone2B-green fluorescent protein ...
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.0805012105
更新日期:2008-08-26 00:00:00
abstract::The mitogen-activated kinase activating death domain protein (MADD) that is differentially expressed in neoplastic vs. normal cells (DENN) was identified as a substrate for c-Jun N-terminal kinase 3, the first demonstration of such an activity for this stress-activated kinase that is predominantly expressed in the bra...
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.95.5.2586
更新日期:1998-03-03 00:00:00
abstract::The decrease with age of the adrenal-secreted dehydroepiandrosterone sulfate (DHEAS) in serum has suggested that it may be causally related to longevity. For the PAQUID [People (Personnes) Aged (Agées) About What (Quid, in Latin)] cohort of elderly subjects, we have previously reported higher DHEAS in men than in wome...
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.121177998
更新日期:2001-07-03 00:00:00
abstract::Proinflammatory macrophages are key mediators in several pathologies; thus, controlling their activation is necessary. The endocannabinoid system is implicated in various inflammatory processes. Here we show that in macrophages, the newly characterized enzyme α/β-hydrolase domain 6 (ABHD6) controls 2-arachidonoylglyce...
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.1314017110
更新日期:2013-10-22 00:00:00
abstract::The coelacanth fish Latimeria chalumnae is the sole surviving species of a phylogenetic lineage that was founded more than 400 million years ago and that has changed morphologically very little since that time. Little is known about the molecular evolution of this "living fossil," considered by some taxonomists to be ...
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.91.23.11065
更新日期:1994-11-08 00:00:00
abstract::Previous studies have established that humans and monkeys with damage to striate cortex are able to detect and localize bright targets within the resultant scotoma. Electrophysiological evidence in monkeys suggests that residual vision also might include sensitivity to direction of visual motion. We tested whether mac...
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.021519698
更新日期:2001-01-02 00:00:00
abstract::Aggregation of marine sponge cells (Microciona prolifera) resembles stimulus-response coupling of higher organisms in which activation of protein kinase C and movements of intracellular Ca provide twin signals. We now report that activators of protein kinase C (phorbol esters) and ionomycin act synergistically to aggr...
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.83.9.2914
更新日期:1986-05-01 00:00:00
abstract::The advent of molecular tension probes for real-time mapping of piconewton forces in living systems has had a major impact on mechanobiology. For example, DNA-based tension probes have revealed roles for mechanics in platelet, B cell, T cell, and fibroblast function. Nonetheless, imaging short-lived forces transmitted...
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.1904034116
更新日期:2019-08-20 00:00:00