Abstract:
:The idea that the first living systems on earth were based on self-replicating RNA molecules has recently become popular as a result of the discovery of ribozymes. However, there are several major problems associated with the prebiotic synthesis of ribonucleotides. In addition, there is the newly recognized problem of enantiomeric cross-inhibition, whereby template-directed polymerization involving one enantiomer of RNA is inhibited strongly by the presence of the other enantiomer. Here we propose that RNA was preceded in the evolution of life by a polymer constructed from flexible, acyclic, probably prochiral nucleotide analogues that were synthesized readily on the primitive earth. Several potentially prebiotic nucleotide analogues are considered in this context, and some of the consequences of this proposal are discussed.
journal_name
Proc Natl Acad Sci U S Aauthors
Joyce GF,Schwartz AW,Miller SL,Orgel LEdoi
10.1073/pnas.84.13.4398subject
Has Abstractpub_date
1987-07-01 00:00:00pages
4398-402issue
13eissn
0027-8424issn
1091-6490journal_volume
84pub_type
杂志文章abstract::Soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) protein interactions at the synaptic vesicle/plasma membrane interface play an essential role in neurotransmitter release. The membrane-proximal region (amino acids 77-90) of the v-SNARE vesicle-associated membrane protein 2 (VAMP 2,...
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.0303274101
更新日期:2004-02-10 00:00:00
abstract::Distinguishing tumor from normal glandular breast tissue is an important step in breast-conserving surgery. Because this distinction can be challenging in the operative setting, up to 40% of patients require an additional operation when traditional approaches are used. Here, we present a proof-of-concept study to dete...
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.1408129111
更新日期:2014-10-21 00:00:00
abstract::Aneuploidy is ubiquitous in cancer, and its phenotypes are inevitably dominant and abnormal. In view of these facts we recently proposed that aneuploidy is sufficient for carcinogenesis generating cancer-specific aneusomies via a chain reaction of autocatalytic aneuploidizations. According to this hypothesis a carcino...
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.251670699
更新日期:2002-05-14 00:00:00
abstract::The molecular basis of pathogen clone emergence is relatively poorly understood. Acquisition of a bacteriophage encoding a previously unknown secreted phospholipase A(2) (designated SlaA) has been implicated in the rapid emergence in the mid-1980s of a new hypervirulent clone of serotype M3 group A Streptococcus. Alth...
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.0607669103
更新日期:2006-10-24 00:00:00
abstract::The operon model was proposed by Jacob and Monod in 1961 to explain the regulation of enzyme synthesis in bacteria. The model requires two genetic elements: a locus i which directs the synthesis of a repressor, and a locus called the operon which contains an operator gene and associated structural genes. The repressor...
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.62.2.550
更新日期:1969-02-01 00:00:00
abstract::The noninvasive detection and quantification of CD8(+) T cells in vivo are important for both the detection and staging of CD8(+) lymphomas and for the monitoring of successful cancer immunotherapies, such as adoptive cell transfer and antibody-based immunotherapeutics. Here, antibody fragments are constructed to targ...
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.1316922111
更新日期:2014-01-21 00:00:00
abstract::We have developed a reliable genetic selection strategy for isolating interacting proteins based on the "hitchhiker" mechanism of the Escherichia coli twin-arginine translocation (Tat) pathway. This method, designated FLI-TRAP (functional ligand-binding identification by Tat-based recognition of associating proteins),...
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.0704048106
更新日期:2009-03-10 00:00:00
abstract::We have generated RANK (receptor activator of NF-kappaB) nullizygous mice to determine the molecular genetic interactions between osteoprotegerin, osteoprotegerin ligand, and RANK during bone resorption and remodeling processes. RANK(-/-) mice lack osteoclasts and have a profound defect in bone resorption and remodeli...
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.97.4.1566
更新日期:2000-02-15 00:00:00
abstract::Analysis of the mRNA capping apparatus of the malaria parasite Plasmodium falciparum illuminates an evolutionary connection to fungi rather than metazoans. We show that P. falciparum encodes separate RNA guanylyltransferase (Pgt1) and RNA triphosphatase (Prt1) enzymes and that the triphosphatase component is a member ...
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.061636198
更新日期:2001-03-13 00:00:00
abstract::A cDNA, cRKIN1, encoding a putative homologue of the yeast (Saccharomyces cerevisiae) SNF1-encoded protein-serine/threonine kinase, has been isolated from a library prepared from rye endosperm mRNA. Northern blot analysis demonstrated the presence of cRKIN1-related transcripts in developing endosperms but not in shoot...
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.88.19.8602
更新日期:1991-10-01 00:00:00
abstract::RNA 3'-phosphate cyclase (RtcA) synthesizes RNA 2',3' cyclic phosphate ends via three steps: reaction with ATP to form a covalent RtcA-(histidinyl-Nε)-AMP intermediate; transfer of adenylate to an RNA 3'-phosphate to form RNA(3')pp(5')A; and attack of the vicinal O2' on the 3'-phosphorus to form a 2',3' cyclic phospha...
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.1115560108
更新日期:2011-12-27 00:00:00
abstract::We examine how the polypeptide chain in protein crystal structures exploits the multivalent hydrogen-bonding potential of bound water molecules. This shows that multiple interactions with a single water molecule tend to occur locally along the chain. A distinctive internal-coordinate representation of the local water-...
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.92.16.7600
更新日期:1995-08-01 00:00:00
abstract::The SRC gene is the prototype for a family of closely related genes whose products have protein-tyrosine kinase activity. We recently described another member of this family, designated FYN, whose cDNA was isolated from normal human fibroblasts. To examine the possible role of FYN as an oncogene, we investigated 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.85.11.3870
更新日期:1988-06-01 00:00:00
abstract::We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microchip sensor consisting of a microfluidic channel and a microfabricated vapor cell (the heart of an atomic magnetometer). Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation-fr...
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.0711505105
更新日期:2008-02-19 00:00:00
abstract::We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M(eta5-C5R5)(CO)2(L) [where M = Mn or Re, R = H or CH3 (Re only); and L = CH4 or C2H6]. In all cases, the methane complexes are found to be shor...
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.0610567104
更新日期:2007-04-24 00:00:00
abstract::Small solutes affect protein and nucleic acid processes because of favorable or unfavorable chemical interactions of the solute with the biopolymer surface exposed or buried in the process. Large solutes also exclude volume and affect processes where biopolymer molecularity and/or shape changes. Here, we develop an 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.1103382108
更新日期:2011-08-02 00:00:00
abstract::The mouse skeletal muscle acetylcholine receptor is regulated, at least in part, by transcriptional mechanisms. As a first step toward defining the cis- and trans-acting factors involved in acetylcholine receptor transcriptional regulation, we examined mouse muscle and fibroblast cells for the presence of DNase I-hype...
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.83.21.8405
更新日期:1986-11-01 00:00:00
abstract::The 2-deoxy-D-glucose method was used to study asymmetries in cerebral metabolic activity in neonatal rats. Left-right asymmetries in 2-deoxy-D-glucose uptake were observed in hippocampus, diencephalon, cortex, and medulla-pons: 2-deoxy-D-glucose incorporation was greater in right hippocampus, right diencephalon, left...
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.78.3.1958
更新日期:1981-03-01 00:00:00
abstract::HeLa cells grown in the presence of [methyl-3H]thymidine contained large amounts of 5-hydroxymethyl-2'-deoxyuridine (HMdU) in their DNA. When the cells were grown in [6-3H]thymidine and their DNA was labeled to the same specific activity, no HMdU was present. When such [6-3H]thymidine-labeled cells were exposed to inc...
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.81.2.318
更新日期:1984-01-01 00:00:00
abstract::Pseudoxanthoma elasticum (PXE) is an autosomal recessive disease characterized by progressive ectopic mineralization of the skin, eyes, and arteries, for which no effective treatment exists. PXE is caused by inactivating mutations in the gene encoding ATP-binding cassette sub-family C member 6 (ABCC6), an ATP-dependen...
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.1319582110
更新日期:2013-12-10 00:00:00
abstract::A close study of the metabolic regulation of hexose transport in a hamster fibroblast mutant, highly defective in the enzyme phosphoglucose isomerase (PGI mutant), reveals the requirement for at least three vectors for transport regulation. The downward regulation of the hexose transport system, called the "transport ...
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.81.4.1126
更新日期:1984-02-01 00:00:00
abstract::IL-7 functions as a trophic factor during T lymphocyte development by a mechanism that is partly based on the induction of Bcl-2, which protects cells from apoptosis. Here we report a mechanism by which cytokine withdrawal activates the prodeath protein Bax. On loss of IL-7 in a dependent cell line, Bax protein transl...
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.96.25.14476
更新日期:1999-12-07 00:00:00
abstract::RNase T2 enzymes are conserved in most eukaryotic genomes, and expression patterns and phylogenetic analyses suggest that they may carry out an important housekeeping role. However, the nature of this role has been elusive. Here we show that RNS2, an intracellular RNase T2 from Arabidopsis thaliana, is essential for n...
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.1009809108
更新日期:2011-01-18 00:00:00
abstract::Previous reconstructions of marine fishing fleets have aggregated data without regard to the artisanal and industrial sectors. Engine power has often been estimated from subsets of the developed world, leading to inflated results. We disaggregated data into three sectors, artisanal (unpowered/powered) and industrial, ...
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.1820344116
更新日期:2019-06-18 00:00:00
abstract::Mycobacterium marinum, a natural pathogen of fish and frogs and an occasional pathogen of humans, is capable of inducing actin tail formation within the cytoplasm of macrophages, leading to actin-based motility and intercellular spread. Actin tail formation by M. marinum is markedly reduced in macrophages deficient in...
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.0504663102
更新日期:2005-10-11 00:00:00
abstract::An ammonia-oxidizing, carbon-fixing archaeon, Candidatus "Nitrosopumilus maritimus," recently was isolated from a salt-water aquarium, definitively confirming that chemoautotrophy exists among the marine archaea. However, in other incubation studies, pelagic archaea also were capable of using organic carbon. It has 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.0510157103
更新日期:2006-04-25 00:00:00
abstract::Genomic clones and cDNA plasmids were isolated for the intermediate filament protein vimentin from chicken. The identity of the various clones was determined both by mRNA selection [Paterson, B. M. & Roberts, B. E. (1981) in Gene Amplification and Analysis, Structural Analysis or Nucleic Acids, eds. Chirikjian, J. G. ...
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.80.4.911
更新日期:1983-02-01 00:00:00
abstract::CCAAT/enhancer-binding protein δ (C/EBPδ) recently emerged as an essential player in the inflammatory response to bacterial infections. C/EBPδ levels increase rapidly after a proinflammatory stimulus, and increasing C/EBPδ levels seem to be indispensable for amplification of the inflammatory response. Here we aimed 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.1202641109
更新日期:2012-06-05 00:00:00
abstract::Melittin messenger RNA from queen bee venom glands has been translated in a cell-free system from wheat germ. A product larger than promelittin is formed which has the carboxy-terminal sequence-Gln-Gln-GlyCOOH. Melittin and promelittin from venom glands terminate in -Gln-GlnCONH2. The possible role of the extra glycin...
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.74.3.975
更新日期:1977-03-01 00:00:00
abstract::Mutational processes of simple sequence repeats (SSRs) in complex genomes are poorly understood. We examined these processes by introducing a two-phase mutation model. In this model, most mutations are single-step changes, but infrequent large jumps in repeat number also occur. We used computer simulations to determin...
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.91.8.3166
更新日期:1994-04-12 00:00:00