Abstract:
:In addition to their well-recognized hepatotropism, all hepatitis B viruses (HBVs) display marked species specificity, growing poorly or not at all in species other than those closely related to their natural hosts. We have examined the molecular basis for this narrow host range, using duck HBV (DHBV) and heron HBV (HHBV) as a model system. HHBV virions will not infect ducks in vivo and infect cultured duck hepatocytes extremely inefficiently in vitro. Mutant HHBV genomes lacking all viral envelope proteins (HHBV env-) can be complemented in trans with DHBV envelope proteins; the resulting pseudotyped virions can efficiently infect duck hepatocytes. Further complementation analysis reveals that of the two viral surface proteins (L and S), it is the L protein that determines host range. Pseudotyping of HHBV env- with DHBV/HHBV chimeric envelope proteins reveals that replacement of as few as 69 amino acids of the pre-S domain of the HHBV L protein by their DHBV counterparts is sufficient to permit infection of duck hepatocytes. These studies indicate that the species-specificity of hepadnaviral infection is determined at the level of virus entry and is governed by the pre-S domain of the viral L protein.
journal_name
Proc Natl Acad Sci U S Aauthors
Ishikawa T,Ganem Ddoi
10.1073/pnas.92.14.6259subject
Has Abstractpub_date
1995-07-03 00:00:00pages
6259-63issue
14eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::At least two kidney epithelial cell lines, the Madin-Darby canine kidney (MDCK) and the murine inner medullary collecting duct line mIMCD-3, can be induced to form branching tubular structures when cultured with hepatocyte growth factor (HGF) plus serum in collagen I gels. In our studies, whereas MDCK cells remained u...
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.92.10.4412
更新日期:1995-05-09 00:00:00
abstract::Electromyographic recordings from individual identified ankle muscles of the 7-day chick embryo (stage 31) were used to determine the organization of motor output at a developmental stage shortly after the onset of spontaneous motility in the leg. During spontaneous motility of the embryo, the electromyographic record...
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.72.4.1245
更新日期:1975-04-01 00:00:00
abstract::One of the issues currently being debated in the ongoing discussion of the pros and cons of today's globalization concerns the effects of greater world trade as well as of the changes in technology on a country's internal distribution of income, especially on skilled versus unskilled wage rates. In this article, I att...
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.1733335100
更新日期:2003-09-16 00:00:00
abstract::Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (Movie S1), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsa...
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.1301826110
更新日期:2013-05-28 00:00:00
abstract::To study the origin of and the degree of T-cell antigen receptor (TCR) diversity of Thy-1+ dendritic epidermal cells (Thy-1+ dECs) in mice, we have developed a monoclonal antibody (mAb 536) to the gamma delta TCR. mAb 536 binds to and stimulates interleukin 2 secretion from Thy-1+ dEC but not cells that express TCR 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.86.11.4185
更新日期:1989-06-01 00:00:00
abstract::Soluble epoxide hydrolase (sEH) is an emerging therapeutic target in a number of diseases that have inflammation as a common underlying cause. sEH limits tissue levels of cytochrome P450 (CYP) epoxides derived from omega-6 and omega-3 polyunsaturated fatty acids (PUFA) by converting these antiinflammatory mediators 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.1422590112
更新日期:2015-01-13 00:00:00
abstract::DNA lesions can block replication forks and lead to the formation of single-stranded gaps. These replication complications are mitigated by DNA damage tolerance mechanisms, which prevent deleterious outcomes such as cell death, genomic instability, and carcinogenesis. The two main tolerance strategies are translesion ...
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.1216894110
更新日期:2013-04-16 00:00:00
abstract::The boreal forests, identified as a critical "tipping element" of the Earth's climate system, play a critical role in the global carbon budget. Recent findings have suggested that terrestrial carbon sinks in northern high-latitude regions are weakening, but there has been little observational evidence to support the 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.1111576109
更新日期:2012-02-14 00:00:00
abstract::A polypeptide transforming growth factor (TGF) that induces anchorage-dependent rat kidney fibroblasts to grow in soft agar has been isolated from human placenta and purified to homogeneity. This polypeptide is classified as a type beta TGF because it does not compete with epidermal growth factor (EGF) for membrane 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.80.12.3676
更新日期:1983-06-01 00:00:00
abstract::We assess the significance of high-frequency variability of environmental parameters (sunlight, precipitation, temperature) for the structure and function of terrestrial ecosystems under current and future climate. We examine the influence of hourly, daily, and monthly variance using the Ecosystem Demography model ver...
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.0912032107
更新日期:2010-05-04 00:00:00
abstract::Hereditary hemochromatosis (HH) is a common chronic human genetic disorder whose hallmark is systemic iron overload. Homozygosity for a mutation in the MHC class I heavy chain paralogue gene HFE has been found to be a primary cause of HH. However, many individuals homozygous for the defective allele of HFE do not deve...
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.091088998
更新日期:2001-04-24 00:00:00
abstract::Acute glaucoma is a sight-threatening condition characterized by a sudden and substantial rise in intraocular pressure (IOP) and consequent retinal ganglion cell (RGC) death. Angle closure glaucoma, a common cause of glaucoma in Asia that affects tens of millions of people worldwide, often presents acutely with loss o...
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.1402819111
更新日期:2014-07-29 00:00:00
abstract::The ability of polynucleotides or polynucleotide duplexes such as poly(I).poly(C) to induce interferon production is proposed to depend on the existence of certain stable glycosidic orientations. It appears that a slight increase in instability of 1--3 kcal/mole (1 cal = 4.184 J) in the conformational regions near 20 ...
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.76.3.1018
更新日期:1979-03-01 00:00:00
abstract::Extracts of cultured human leukemic tissues increased the spleen focus-forming activity of Friend leukemia virus preparations in BALB/c and other partially resistant mice. Such mice carry the Fv-1(b) gene, which inhibits the expression of helper virus indigenous to the Friend virus complex, and allows co-infecting leu...
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.68.10.2391
更新日期:1971-10-01 00:00:00
abstract::We used electron cryotomography and subtomogram averaging to determine the in situ structures of mitochondrial ATP synthase dimers from two organisms belonging to the phylum euglenozoa: Trypanosoma brucei, a lethal human parasite, and Euglena gracilis, a photosynthetic protist. At a resolution of 32.5 Å and 27.5 Å, 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.1612386114
更新日期:2017-01-31 00:00:00
abstract::The tumorigenic properties of Rous sarcoma virus are attributable to a 60,000-dalton protein, pp60v--src, encoded by a single viral gene, v-src. A homologous gene, c-src, that contains the information for a 60,000-dalton protein, pp60c--src, has been identified in all tested vertebrate cells. By screening a recombinan...
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.78.9.5842
更新日期:1981-09-01 00:00:00
abstract::Mineralogical processes taking place close to equilibrium, or with very slow kinetics, are difficult to quantify precisely. The determination of ultraslow dissolution/precipitation rates would reveal characteristic timing associated with these processes that are important at geological scale. We have designed an advan...
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.1105233108
更新日期:2011-09-20 00:00:00
abstract::The Helicobacter pylori immunodominant protein, CagA, is associated with severe gastritis and carcinoma. Injection of CagA into gastric epithelial cells by type IV secretion leads to actin-cytoskeletal rearrangements and cell scattering. CagA has been reported to have no role in the induction of transcription factor 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.0409873102
更新日期:2005-06-28 00:00:00
abstract::In eukaryotic cells the concentration of dNTP is highest in S phase and lowest in G1 phase and is controlled by ribonucleotide reductase (RNR). RNR activity is eliminated in all eukaryotes in G1 phase by a variety of mechanisms: transcriptional regulation, small inhibitory proteins, and protein degradation. After acti...
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.0610585104
更新日期:2007-01-23 00:00:00
abstract::Immediately after adsorption, phages T4 and T5 induce a partial depolarization of the host cytoplasmic membrane. Infected bacteria respond to this phage-induced effect by a repolarization that leads to a new steady state of reduced membrane potential. The rate and extent of repolarization are adjusted to the intensity...
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.78.1.215
更新日期:1981-01-01 00:00:00
abstract::The foundation of marine coral reef ecosystems is calcium carbonate accumulated primarily by the action of hard corals (Coelenterata: Anthozoa: Scleractinia). Colonial hard coral polyps cover the surface of the reef and deposit calcium carbonate as the aragonite polymorph, stabilized into a continuous calcareous skele...
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.211439698
更新日期:2001-10-09 00:00:00
abstract::A general model for the contractility of cells is presented that accounts for the dynamic reorganization of the cytoskeleton. The model is motivated by three key biochemical processes: (i) an activation signal that triggers actin polymerization and myosin phosphorylation, (ii) the tension-dependent assembly of the act...
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.0605837103
更新日期:2006-09-19 00:00:00
abstract::The transcription factor and tumor suppressor protein p53 is frequently inactivated in human cancers. In many cases, p53 gene mutations result in high levels of inactive, full-length p53 protein with one amino acid change in the core domain that recognizes p53 DNA-binding sites. The ability to endow function to mutate...
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.0401162101
更新日期:2004-04-06 00:00:00
abstract::RNA polymerase pausing represents an important mechanism of transcriptional regulation. In this study, we use a single-molecule transcription assay to investigate the effect of template base-pair composition on pausing by RNA polymerase II and the evolutionarily distinct mitochondrial polymerase Rpo41. For both enzyme...
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.1205063109
更新日期:2012-06-05 00:00:00
abstract::The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 μm in diameter and adenine-thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they enti...
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.1320670111
更新日期:2014-03-18 00:00:00
abstract::Two new forms of carboxypeptidase B have been isolated from spontaneously activated bovine pancreatic juice. The fully active enzymes contain an internal split at residues 92-93 and 95-96, respectively. Sequenator analysis of the amino terminal segments of the two chains of the enzyme has extended the sequence informa...
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.68.6.1226
更新日期:1971-06-01 00:00:00
abstract::Adenosine deaminase (ADA; adenosine aminohydrolase, EC 3.5.4.4) deficiency is one cause of the genetic disease severe combined immunodeficiency. To identify mutations responsible for ADA deficiency, we synthesized cDNAs to ADA mRNAs from two cell lines, GM2756 and GM2825A, derived from ADA-deficient immunodeficient pa...
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.84.16.5947
更新日期:1987-08-01 00:00:00
abstract::Hox genes are located in highly conserved clusters. The significance of this organization is unclear, but one possibility is that regulatory regions for individual genes are dispersed throughout the cluster and shared with other Hox genes. This hypothesis is supported by studies on several Hox genes in which even larg...
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.93.6.2426
更新日期:1996-03-19 00:00:00
abstract::It has long been known that cholera outbreaks can be initiated when Vibrio cholerae, the bacterium that causes cholera, is present in drinking water in sufficient numbers to constitute an infective dose, if ingested by humans. Outbreaks associated with drinking or bathing in unpurified river or brackish water may dire...
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.97.4.1438
更新日期:2000-02-15 00:00:00
abstract::Long-term memory relies on modulation of synaptic connections in response to experience. This plasticity involves trafficking of AMPA receptors (AMPAR) and alteration of spine morphology. Arc, a gene induced by synaptic activity, mediates the endocytosis of AMPA receptors and is required for both long-term and homeost...
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.1006546107
更新日期:2010-10-19 00:00:00