Abstract:
:Comparisons were made of the T1 ribonuclease digests of 32P-labeled nucleolar 45S RNA of intact Novikoff hepatoma cells and the RNA synthesized in vitro by isolated nucleoli. Approximately 200 oligonucleotide spots were found in the two-dimensional chromatogram of 45S nucleolar RNA labeled in vivo, which includes fragments of 18S and 28S rRNA and nonconserved spacer regions; four spots containing 2'-O-methyl nucleotides were not found in the corresponding pattern of RNA labeled in vitro. This high degree of fidelity was retained in the patterns of spots from the RNA produced with nucleolar chromatin as template. This specific expression of rDNA was lost when the nucleolar chromatin was completely deproteinized. Specific spots found in the control patterns were absent and many nonspecific oligonucleotides were found to be labeled. A similar nonspecific chromatogram pattern was found when nucleolar chromatin was transcribed with RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) of Escherichia coli. These results show that specificity of genetic expression in vitro of isolated chromatin of eukaryotic systems is dependent on the chromatin-associated proteins and the type of RNA polymerase present.
journal_name
Proc Natl Acad Sci U S Aauthors
Ballal NR,Choi YC,Mouche R,Busche Hdoi
10.1073/pnas.74.6.2446subject
Has Abstractpub_date
1977-06-01 00:00:00pages
2446-50issue
6eissn
0027-8424issn
1091-6490journal_volume
74pub_type
杂志文章abstract::We describe here a third region of variability in human fibronectin (FN) due to alternative RNA splicing. Two other positions of alternative splicing have been reported previously (ED and IIICS). The third region involves a 273-nucleotide exon encoding exactly one 91-amino acid repeat of type III homology, located bet...
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.84.20.7179
更新日期:1987-10-01 00:00:00
abstract::The receptor 2B4 belongs to the Ig superfamily and is found on the surface of all murine natural killer (NK) cells as well as T cells displaying non-MHC-restricted cytotoxicity. Previous studies have suggested that 2B4 is an activating molecule because cross-linking of this receptor results in increased cytotoxicity 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.96.7.3870
更新日期:1999-03-30 00:00:00
abstract::The hypothetical scanning (HS) method is a general approach for calculating the absolute entropy and free energy by analyzing Boltzmann samples obtained by Monte Carlo (MC) or molecular dynamics techniques. With HS applied to a fluid, each configuration i of the sample is reconstructed by adding its atoms gradually 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.0308197101
更新日期:2004-06-22 00:00:00
abstract::Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we sho...
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.0805600105
更新日期:2008-12-16 00:00:00
abstract::Leukemia cell lines of the monocytic series (HL-60, U-937, and P388D1) produce a hepatocyte-stimulating factor (HSF) following induction of differentiation with phorbol diester. In 24-72 hr, these leukemia cells produce 2-30% the amount of HSF as human peripheral blood monocytes. Cells of the series at earlier stages ...
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.82.5.1443
更新日期:1985-03-01 00:00:00
abstract::Cell adhesion molecules (CAMs) may act as regulators of morphogenesis by constraining cell motion, forming borders, and controlling intercellular communications that lead to embryonic induction. This postulated causal role of CAMs in inductive events was tested here in an in vitro system of feather induction. In the 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.83.21.8235
更新日期:1986-11-01 00:00:00
abstract::NRSF/REST is a protein that silences transcription of a number of genes that contain a DNA element called the neuron-restrictive silencer element (NRSE). During embryogenesis, REST is expressed ubiquitously in nonneural cells, but is down-regulated during differentiation of neural progenitors into neurons. REST is als...
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.050578797
更新日期:2000-02-29 00:00:00
abstract::Tolerance and resistance provide hosts with two distinct defense strategies against parasitism. In resistance the hosts "fight" the parasite directly, whereas in tolerance the hosts fight the disease by ameliorating the damage that infection causes. There is increasing recognition that the two mechanisms may exhibit v...
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.0809558105
更新日期:2008-12-30 00:00:00
abstract::We have previously identified a cellular transcription factor, ATF, which is involved in the expression of multiple adenovirus E1a-inducible genes. Here we show that ATF also binds to regulatory elements in cellular cAMP-inducible promoters. In these cellular promoters, ATF binds to a consensus sequence that has been ...
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.85.10.3396
更新日期:1988-05-01 00:00:00
abstract::Myelin basic proteins (MBP) are major constituents of the myelin sheath of oligodendrocytes and Schwann cells in the central nervous system and the peripheral nervous system, respectively. We previously showed that MBP-related transcripts are present in the bone marrow and the immune system. These mRNAs are transcribe...
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.122079599
更新日期:2002-06-25 00:00:00
abstract::The mouse p19Arf (human p14ARF) tumor suppressor protein, encoded in part from an alternative reading frame of the Ink4a (Cdkn2a) gene, inhibits the Mdm2 E3 ubiquitin ligase to activate p53. Arf is not expressed in most normal tissues of young mice but is induced by high thresholds of aberrant hyperproliferative signa...
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.1707292114
更新日期:2017-07-11 00:00:00
abstract::The visual system of the macaque monkey has provided a useful model for understanding the neural basis of human vision, yet, there are few detailed comparisons of neural populations other than photoreceptors for the two species. Using intracellular staining in an in vitro preparation of the isolated and intact human r...
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.89.20.9666
更新日期:1992-10-15 00:00:00
abstract::Posttranslational modifications (PTMs) are important physiological means to regulate the activities and structures of central regulatory proteins in health and disease. Small GTPases have been recognized as important molecules that are targeted by PTMs during infections of mammalian cells by bacterial pathogens. The 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.1917549117
更新日期:2020-03-17 00:00:00
abstract::Picomole amounts of oligodeoxynucleotides [polydeoxyadenylic acids, (dA)40-60] were baseline resolved and analyzed in less than 8 min by high-performance capillary electrophoresis with polyacrylamide gels. In addition, fast analysis of a crude 70-mer oligodeoxynucleotide and a slab gel-purified 99-mer oligodeoxynucleo...
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.85.24.9660
更新日期:1988-12-01 00:00:00
abstract::Telomere syndromes have their most common manifestation in lung disease that is recognized as idiopathic pulmonary fibrosis and emphysema. In both conditions, there is loss of alveolar integrity, but the underlying mechanisms are not known. We tested the capacity of alveolar epithelial and stromal cells from mice with...
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.1504780112
更新日期:2015-04-21 00:00:00
abstract::As an adaptation to infrequent access to water, terrestrial mammals produce urine that is hyperosmotic to plasma. To prevent osmotic diuresis by the large quantity of urea generated by protein catabolism, the kidney epithelia contain facilitative urea transporters (UTs) that allow rapid equilibration between the urina...
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.1207362109
更新日期:2012-07-10 00:00:00
abstract::Within the trimeric HIV-1 envelope (Env) spike, the first and second variable loops (V1V2 region) and the third variable loop (V3) of the gp120 subunit play dual roles in antibody recognition, because they contain neutralization epitopes and also participate in epitope masking. The spatial relationships between V1V2 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.1104840108
更新日期:2011-12-13 00:00:00
abstract::The 26S proteasome, a molecular machine responsible for regulated protein degradation, consists of a proteolytic core particle (20S CP) associated with 19S regulatory particles (19S RPs) subdivided into base and lid subcomplexes. The assembly of 19S RP base subcomplex is mediated by multiple dedicated chaperones. Amon...
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.1116538109
更新日期:2012-04-24 00:00:00
abstract::Isolated developing plastids from greening cucumber cotyledons or from photoperiodically grown pea seedlings incorporated (14)C-labeled 5-aminolevulinic acid (ALA) into chlorophyll (Chl). Incorporation was light dependent, enhanced by S-adenosylmethionine, and linear for 1 hr. The in vitro rate of Chl synthesis from 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.82.16.5370
更新日期:1985-08-01 00:00:00
abstract::Mouse tumor C1300 has been established in tissue culture. The cells have a round cell morphology in both the subcutaneous tumor and in suspension culture. However, when given a surface on which to attach, they send out processes up to 3 mm in length and assume the morphology of mature neurons. The attached cells are 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.64.1.316
更新日期:1969-09-01 00:00:00
abstract::Many aspects of plant development, including patterning and tropisms, are largely dependent on the asymmetric distribution of the plant signaling molecule auxin. Auxin transport inhibitors (ATIs), which interfere with directional auxin transport, have been essential tools in formulating this concept. However, despite ...
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.0711414105
更新日期:2008-03-18 00:00:00
abstract::The great mass extinctions of the fossil record were a major creative force that provided entirely new kinds of opportunities for the subsequent explosive evolution and diversification of surviving clades. Today, the synergistic effects of human impacts are laying the groundwork for a comparably great Anthropocene mas...
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.0802812105
更新日期:2008-08-12 00:00:00
abstract::A chromosomal locus required for copper resistance and competitive fitness was cloned from a strain of Pseudomonas fluorescens isolated from copper-contaminated agricultural soil. Sequence analysis of this locus revealed six open reading frames with homology to genes involved in cytochrome c biogenesis in other bacter...
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.93.14.7315
更新日期:1996-07-09 00:00:00
abstract::The spatial extent of the cortical filters selective for different spatial frequencies and orientations is limited. We studied psychophysically how information from the local filters is integrated into global pattern shapes, i.e., whether performance in the identification of a global pattern consisting of small, local...
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.94.15.8267
更新日期:1997-07-22 00:00:00
abstract::The FKBP12-rapamycin-associated protein (FRAP; also called RAFT1/mTOR) regulates translation initiation and entry into the cell cycle. Depriving cells of amino acids or treating them with the small molecule rapamycin inhibits FRAP and results in rapid dephosphorylation and inactivation of the translational regulators ...
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.96.8.4438
更新日期:1999-04-13 00:00:00
abstract::The autophagic ubiquitin-like protein (ublp) autophagy-related (ATG)12 is a component of the ATG12∼ATG5-ATG16L1 E3 complex that promotes lipid conjugation of members of the LC3 ublp family. A role of ATG12 in the E3 complex is to recruit the E2 enzyme ATG3. Here we report the identification of the ATG12 binding 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.1314755110
更新日期:2013-11-19 00:00:00
abstract::Peroxisomes play an essential role in a number of different metabolic pathways, including the beta-oxidation of a distinct set of fatty acids and fatty acid derivatives. The importance of the peroxisomal beta-oxidation system in humans is made apparent by the existence of a group of inherited diseases in which peroxis...
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.95.5.2128
更新日期:1998-03-03 00:00:00
abstract::Several models have been proposed for the infectious agents that cause human Creutzfeldt-Jakob disease (CJD) and sheep scrapie. Purified proteins and extracted nucleic acids are not infectious. To further identify the critical molecular components of the CJD agent, 120S infectious material with reduced prion 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.92.11.5124
更新日期:1995-05-23 00:00:00
abstract::Mitogen-stimulated scheduled DNA synthesis and DNA excision repair in human lymphocytes, as well as DNA polymerase a activity in a cell-free system, were inhibited by an electrophilic metabolite of benzo[a]pyrene. This metabolite, (+/-)-anti-(7r,8t)-dihydroxy-(9,10t)-epoxy-7,8,9,10-tetrahyd robenzo[a]pyrene (BPDE), 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.81.17.5300
更新日期:1984-09-01 00:00:00
abstract::Burkitt's lymphomas, linked by previous studies with the DNA-containing Epstein-Barr virus, contain an RNA related in sequence to that of Rauscher leukemia virus. The present study establishes that the viral-related RNA found in Burkitt's tumors is a 70S component encapsulated with RNA-instructed DNA polymerase in a 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.70.3.737
更新日期:1973-03-01 00:00:00