Abstract:
:Bone morphogenetic protein 4 (BMP-4) induces ventral mesoderm but represses dorsal mesoderm formation in Xenopus embryos. We show that BMP-4 inhibits two signaling pathways regulating dorsal mesoderm formation, the induction of dorsal mesoderm (Spemann organizer) and the dorsalization of ventral mesoderm. Ectopic expression of BMP-4 RNA reduces goosecoid and forkhead-1 transcription in whole embryos and in activin-treated animal cap explants. Embryos and animal caps overexpressing BMP-4 transcribe high levels of genes expressed in ventral mesoderm (Xbra, Xwnt-8, Xpo, Mix.1, XMyoD). The Spemann organizer is ventralized in these embryos; abnormally high levels of Xwnt-8 mRNA and low levels of goosecoid mRNA are detected in the organizer. In addition, the organizer loses the ability to dorsalize neighboring ventral marginal zone to muscle. Overexpression of BMP-4 in ventral mesoderm inhibits its response to dorsalization signals. Ventral marginal zone explants ectopically expressing BMP-4 form less muscle when treated with soluble noggin protein or when juxtaposed to a normal Spemann organizer in comparison to control explants. Endogenous BMP-4 transcripts are downregulated in ventral marginal zone explants dorsalized by noggin, in contrast to untreated explants. Thus, while BMP-4 inhibits noggin protein activity, noggin downregulates BMP-4 expression by dorsalizing ventral marginal zone to muscle. Noggin and BMP-4 activities may control the lateral extent of dorsalization within the marginal zone. Competition between these two molecules may determine the final degree of muscle formation in the marginal zone, thus defining the border between dorsolateral and ventral mesoderm.
journal_name
Proc Natl Acad Sci U S Aauthors
Re'em-Kalma Y,Lamb T,Frank Ddoi
10.1073/pnas.92.26.12141subject
Has Abstractpub_date
1995-12-19 00:00:00pages
12141-5issue
26eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::In this article, we address the problem of modeling generic features of structurally but not textually related DNA motifs, that is, motifs whose consensus sequences are entirely different but nevertheless share "metasequence features" reflecting similarities in the DNA-binding domains of their associated protein recog...
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.0403564101
更新日期:2004-07-20 00:00:00
abstract::Cocaine exposure in utero causes severe alterations in the development of the central nervous system. To study the basis of these teratogenic effects in vitro, we have used cocultures of neurons and glial cells from mouse embryonic brain. Cocaine selectively affected embryonic neuronal cells, causing first a dramatic ...
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.92.24.11029
更新日期:1995-11-21 00:00:00
abstract::We report the presence of protein kinase C (PKC) in ejaculated human sperm as revealed by enzymatic activity assay and indirect immunohistochemistry. PKC is localized in the equatorial segment and in the principal piece of the tail. Addition of phorbol 12-myristate 13-acetate resulted in increased flagellar motility 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.87.18.7305
更新日期:1990-09-01 00:00:00
abstract::The hypothalamic arcuate nucleus is involved in the control of energy intake and expenditure and may participate in the pathogenesis of eating disorders such as anorexia nervosa (AN) and bulimia nervosa (BN). Two systems are of particular interest in this respect, synthesizing alpha-melanocyte-stimulating hormone (alp...
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.222658699
更新日期:2002-12-24 00:00:00
abstract::Recent research links diet-induced obesity (DIO) with impaired immunity, although the underlying mechanisms remain unclear. We find that the induction of inducible NO synthase (iNOS) and cytokines is suppressed in mice with DIO and in bone marrow macrophages (BMMPhi) from mice with DIO exposed to an oral pathogen, Por...
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.0904412106
更新日期:2009-06-30 00:00:00
abstract::The oxidative capacity of cat skeletal muscles (soleus, gracilis, and gracilis chronically stimulated for 28 days) was derived from the total mitochondrial content in the muscle, the surface area of mitochondrial inner membranes, and respiratory activities of isolated mitochondria. Mitochondrial content was estimated ...
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.86.5.1583
更新日期:1989-03-01 00:00:00
abstract::One of the technical bottlenecks in producing nonhuman primate models is that current assisted reproductive techniques, such as in vitro culture and frozen conservation of multicell-stage embryos, often result in poor embryo quality and subsequently lead to low birth rates. We investigated whether pronuclear embryo tr...
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.0805639105
更新日期:2008-09-02 00:00:00
abstract::Although soft devices (grippers, actuators, and elementary robots) are rapidly becoming an integral part of the broad field of robotics, autonomy for completely soft devices has only begun to be developed. Adaptation of conventional systems of control to soft devices requires hard valves and electronic controls. This ...
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.1820672116
更新日期:2019-04-16 00:00:00
abstract::The central nitrogen metabolic circuit in enteric bacteria consists of three enzymes: glutamine synthetase, glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH). With the carbon skeleton provided by 2-oxoglutarate, ammonia/ammonium (NH(4)(+)) is assimilated into two central nitrogen intermediates, glutamate 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.0703360104
更新日期:2007-05-29 00:00:00
abstract::Eccentricity, obliquity, and precession are cyclic parameters of the Earth's orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce "grand orbital cycles," but the behavior and the paleoenvironment...
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.1419946112
更新日期:2015-10-13 00:00:00
abstract::Given their relatively small area, mangroves and their organic sediments are of disproportionate importance to global carbon sequestration and carbon storage. Peat deposition and preservation allows some mangroves to accrete vertically and keep pace with sea-level rise by growing on their own root remains. In this stu...
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.1519774113
更新日期:2016-04-19 00:00:00
abstract::Escherichia coli infections, a leading cause of septic shock, remain a major threat to human health because of the fatal action to endotoxin (LPS). Therapeutic attempts to neutralize endotoxin currently focus on inhibiting the interaction of the toxic component lipid A with myeloid differentiating factor 2, which form...
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.1209253109
更新日期:2012-12-18 00:00:00
abstract::Paired immunoglobulin-like type 2 receptor α (PILRα) and β (PILRβ) belong to the PILR family and are related to innate immune regulation in various species. Despite their high sequence identity, PILRα and PILRβ are shown to have variant sialic acid (SA) binding avidities. To explore the molecular basis of this interac...
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.1320716111
更新日期:2014-06-03 00:00:00
abstract::The early steps in the biosynthesis of Taxol involve the cyclization of geranylgeranyl diphosphate to taxa-4(5),11(12)-diene followed by cytochrome P450-mediated hydroxylation at C5, acetylation of this intermediate, and a second cytochrome P450-dependent hydroxylation at C10 to yield taxadien-5 alpha-acetoxy-10 beta-...
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.98.4.1501
更新日期:2001-02-13 00:00:00
abstract::The reversible association of alpha and beta gamma subunits of GTP-binding proteins is important for signal transmission from a variety of cell-surface receptors to intracellular effectors. Previous work showed that 1,6-bis(maleimido)hexane, which crosslinks cysteine residues, crosslinks alpha o and alpha i-1 to beta ...
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.90.21.10295
更新日期:1993-11-01 00:00:00
abstract::The DC and DX subregions of the human major histocompatibility complex (MHC) have been cloned from a cosmid library made from a human B-cell line, Priess. The DC subregion, 48 kilobases, includes the DC alpha and DC beta genes. A second DC-like region, the DX subregion, 35 kilobases, contains the DX alpha gene and a 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.82.10.3410
更新日期:1985-05-01 00:00:00
abstract::The self-organization of multicomponent tetrarosette assemblies into ordered nanostructures on graphite surfaces has been studied by atomic force microscopy (AFM). Real-space information on the level of individual molecules allowed us to analyze the underlying structure in unprecedented detail. In highly ordered nanor...
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.072685399
更新日期:2002-04-16 00:00:00
abstract::The tightly coupled nature of the reaction sequence catalyzed by monoterpene cyclases has precluded direct observation of the topologically required isomerization step leading from geranyl pyrophosphate to the presumptive, enzyme-bound, tertiary allylic intermediate linalyl pyrophosphate, which ultimately cyclizes 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.84.14.4856
更新日期:1987-07-01 00:00:00
abstract::The identities between homogeneous expressions in rank 1 vectors and rank n - 1 covectors in a Grassmann-Cayley algebra of rank n, in which one set occurs multilinearly, are shown to represent a set of dimension-independent identities. The theorem yields an infinite set of nontrivial geometric identities from a given ...
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.92.6.2323
更新日期:1995-03-14 00:00:00
abstract::Estrogen receptors (ERs) protect pancreatic islet survival in mice through rapid extranuclear actions. ERalpha also enhances insulin synthesis in cultured islets. Whether ERalpha stimulates insulin synthesis in vivo and, if so, through which mechanism(s) remain largely unknown. To address these issues, we generated 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.0914501107
更新日期:2010-07-20 00:00:00
abstract::The Esx secretion pathway is conserved across Gram-positive bacteria. Esx-1, the best-characterized system, is required for virulence of Mycobacterium tuberculosis, although its precise function during infection remains unclear. Esx-3, a paralogous system present in all mycobacterial species, is required for growth 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.0900589106
更新日期:2009-11-03 00:00:00
abstract::The plasmid construct pSVO-CAT has been used to test adenovirus promoter activities in the unmethylated or methylated state. We have now observed that the E2A late promoter of adenovirus type 2 (Ad2) DNA also activated the chloramphenicol acetyltransferase (CAT) gene upon transfection of the pAd2E2A-CAT construct into...
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.83.6.1598
更新日期:1986-03-01 00:00:00
abstract::Immunoprecipitation of proteins extracted from metabolically labeled human glioblastoma and fibrosarcoma cells with antiserum to platelet-derived growth factor (PDGF) showed that these cells express and secrete proteins that are recognized specifically by the antiserum. The molecular masses of immunoprecipitated prote...
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.82.8.2404
更新日期:1985-04-01 00:00:00
abstract::Understanding the different categories of facial expressions of emotion regularly used by us is essential to gain insights into human cognition and affect as well as for the design of computational models and perceptual interfaces. Past research on facial expressions of emotion has focused on the study of six basic ca...
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.1322355111
更新日期:2014-04-15 00:00:00
abstract::Exposing primary cultures of cerebellar granule neurons to 100 nM phorbol 12-myristate 13-acetate (PMA) for 24 hr decreases the Ca2+/phosphatidylserine/diolein-dependent protein kinase C (PKC; ATP:protein phosphotransferase, EC 2.7.1.37) by approximately 90% in the 100,000 x g supernatant and pellet fractions of neuro...
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.87.5.1983
更新日期:1990-03-01 00:00:00
abstract::Tumor-promoting phorbol esters affect the ability of mouse hematopoietic progenitor cells to form morphologically recognizable colonies in culture. They induce myeloid progenitor cells to form colonies of the monocyte/macrophage type in the absence of exogenous granulocyte/macrophage colony-stimulating factor. Convers...
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.78.7.4402
更新日期:1981-07-01 00:00:00
abstract::The central questions of bacterial ecology and evolution require a method to consistently demarcate, from the vast and diverse set of bacterial cells within a natural community, the groups playing ecologically distinct roles (ecotypes). Because of a lack of theory-based guidelines, current methods in bacterial systema...
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.0712205105
更新日期:2008-02-19 00:00:00
abstract::That the yolk proteins (YPs), or vitellins, stored in the oocytes of insects are a nutritional store for subsequent embryogenesis has long been assumed. Exhaustive data base searching programs revealed highly significant sequence similarity between the three YPs of Drosophila melanogaster and part of the triacylglycer...
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.85.5.1554
更新日期:1988-03-01 00:00:00
abstract::In recent years, advertisers and magazine editors have been widely criticized for taking digital photo retouching to an extreme. Impossibly thin, tall, and wrinkle- and blemish-free models are routinely splashed onto billboards, advertisements, and magazine covers. The ubiquity of these unrealistic and highly idealize...
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.1110747108
更新日期:2011-12-13 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