Abstract:
:Serum provides growth factors that regulate and limit the growth of normal cells in tissue culture. Animal cells that are malignantly transformed usually exhibit diminished serum requirements for growth in culture. We have used a defined, serum-free medium to determine which of these growth factors becomes dispensable for the growth of transformed Syrian and Chinese hamster fibroblast cells. The medium's four growth factors-epidermal growth factor (EGF), insulin, fibroblast growth factor, and transferrin-were added or omitted as desired. A decreased requirement for EGF was most closely related to tumorigenicity of chemically (ethyl methanesulfonate) transformed cells in nude mice. All lines examined retained their requirement for transferrin, which is needed throughout the growth cycle, in contrast to the other factors, which are needed primarily in G(1) phase. Lines that had lost their EGF requirement but had retained their insulin requirement were arrested in G(1) by insulin deficiency, indicating that their growth control system remained. Mutagenesis with ethyl methanesulfonate can also create requirements of the transformed cells for unknown factors in serum. We conclude that an initial step that reduces the serum requirement in culture, and in tumorigenesis, is relaxation of the growth-regulatory function of EGF.
journal_name
Proc Natl Acad Sci U S Aauthors
Cherington PV,Smith BL,Pardee ABdoi
10.1073/pnas.76.8.3937subject
Has Abstractpub_date
1979-08-01 00:00:00pages
3937-41issue
8eissn
0027-8424issn
1091-6490journal_volume
76pub_type
杂志文章abstract::A site that is preferentially cleaved by the single-strand-specific endonuclease from Aspergillus oryzae was located in vitro 180 base pairs upstream from the 5' end of the chicken pro-alpha 2(I) collagen gene. It is found in supercoiled plasmids with a negative superhelical density of -0.024 or more but not in linear...
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.81.6.1659
更新日期:1984-03-01 00:00:00
abstract::We have identified, cultured, characterized, and propagated adult pluripotent stem cells (PSC) from a subset of human peripheral blood monocytes. These cells, which in appearance resemble fibroblasts, expand in the presence of macrophage colony-stimulating factor and display monocytic and hematopoietic stem cell marke...
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.0536882100
更新日期:2003-03-04 00:00:00
abstract::Activated macrophages are described as classically activated or M1 type and alternatively activated or M2 type, depending on their response to proinflammatory stimuli and the expression of genetic markers including iNOS, arginase1, Ym1, and Fizz1. Here we report that Akt kinases differentially contribute to macrophage...
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.1119038109
更新日期:2012-06-12 00:00:00
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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.052707699
更新日期:2002-03-05 00:00:00
abstract::The proinflammatory cytokine interleukin 1 (IL-1) activates the transcription of many genes encoding acute phase and proinflammatory proteins, a function mediated primarily by the transcription factor NF-kappaB. An early IL-1 signaling event is the recruitment of the Ser/Thr kinase IRAK to the type I IL-1 receptor (IL...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.94.24.12829
更新日期:1997-11-25 00:00:00
abstract::Magnetic field fluctuations arising from fundamental spins are ubiquitous in nanoscale biology, and are a rich source of information about the processes that generate them. However, the ability to detect the few spins involved without averaging over large ensembles has remained elusive. Here, we demonstrate the detect...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1300640110
更新日期:2013-07-02 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.95.18.10832
更新日期:1998-09-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2007-05-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.92.12.5684
更新日期:1995-06-06 00:00:00
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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.85.24.9640
更新日期:1988-12-01 00:00:00
abstract::We synthesized a series of octapeptide analogs of somatostatin, containing N-terminal tryptophan or another amino acid followed by the hexapeptide sequences Cys-Phe-D-Trp-Lys-Thr-Cys or Cys-Tyr-D-Trp-Lys-Val-Cys and a C-terminal threoninamide or tryptophanamide. After purification by HPLC, the inhibitory activities of...
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.84.8.2502
更新日期:1987-04-01 00:00:00
abstract::Muscarinic acetylcholine receptors (mAChR) in the embryonic chicken heart undergo agonist-induced internalization and a subsequent decrease in receptor number (downregulation). Cloning studies have identified two subtypes of mAChR expressed in the embryonic chicken heart, the cm2 and cm4 receptors. We report here that...
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.89.11.5035
更新日期:1992-06-01 00:00:00
abstract::Age-related degeneration of basal forebrain cholinergic neurons (BFCNs) contributes to cognitive decline in Alzheimer's disease and Down's syndrome. With aging, the partial trisomy 16 (Ts65Dn) mouse model of Down's syndrome exhibited reductions in BFCN size and number and regressive changes in the hippocampal terminal...
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.181219298
更新日期:2001-08-28 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
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更新日期:1988-05-01 00:00:00
abstract::It is shown that a very simple semiempirical equation represents quite accurately the thermodynamic properties of aqueous sodium chloride from 373 to 823 K. The equation comprises one Margules term and a Debye-Hückel term. Just the one Margules parameter is freely adjustable because the Debye-Hückel parameter is deter...
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.80.24.7689
更新日期:1983-12-01 00:00:00
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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.2134250100
更新日期:2003-10-28 00:00:00
abstract::The E6 protein of the high-risk human papillomaviruses inactivates the tumor suppressor protein p53 by stimulating its ubiquitinylation and subsequent degradation. Ubiquitinylation is a multistep process involving a ubiquitin-activating enzyme, one of many distinct ubiquitin-conjugating enzymes, and in certain cases, ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.92.8.3264
更新日期:1995-04-11 00:00:00
abstract::A paradigm of evolutionary biology is that adaptation and reproductive isolation are caused by a nearly infinite number of mutations of individually small effect. Here, we test this hypothesis by investigating the genetic basis of pollinator discrimination in two closely related species of monkeyflowers that differ in...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-12-16 00:00:00
abstract::Human interleukin 12 and interleukin 23 (IL12/23) influence susceptibility or resistance to multiple diseases. However, the reasons underlying individual differences in IL12/23 sensitivity remain poorly understood. Here we report that in human peripheral blood mononuclear cells (PBMCs) and inflamed lungs, the majority...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2015-12-15 00:00:00
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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.1808976116
更新日期:2019-04-23 00:00:00
abstract::In a well networked community, there is intense social interaction, and information disseminates briskly and broadly. This is important if the environment is volatile (i.e., keeps changing) and individuals never stop searching for fresh opportunities. Here, we present a simple model that attributes the rise of a dynam...
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.0305684101
更新日期:2004-02-10 00:00:00
abstract::Improving global yields of important agricultural crops is a complex challenge. Enhancing yield and resource use by engineering improvements to photosynthetic carbon assimilation is one potential solution. During the last 40 million years C(4) photosynthesis has evolved multiple times, enabling plants to evade the cat...
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.1109503108
更新日期:2011-08-30 00:00:00
abstract::Myosins, a large family of actin-based motors, have one or two heavy chains with one or more light chains associated with each heavy chain. The heavy chains have a (generally) N-terminal head domain with an ATPase and actin-binding site, followed by a neck domain to which the light chains bind, and a C-terminal tail d...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2000-11-07 00:00:00
abstract::The global financial crisis has precipitated an increasing appreciation of the need for a systemic perspective toward financial stability. For example: What role do large banks play in systemic risk? How should capital adequacy standards recognize this role? How is stability shaped by concentration and diversification...
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.1213767109
更新日期:2012-11-06 00:00:00
abstract::Influenza A virus (IAV) has a segmented genome, which (i) allows for exchange of gene segments in coinfected cells, termed reassortment, and (ii) necessitates a selective packaging mechanism to ensure incorporation of a complete set of segments into virus particles. Packaging signals serve as segment identifiers and 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.1818494116
更新日期:2019-03-05 00:00:00
abstract::A typical molecular ion mass spectrum consists of a sum of signals from species of various possible isotopic compositions. Only the monoisotopic peak (e.g., all carbons are 12C; all nitrogens are 14N, etc.) has a unique elemental composition. Every other isotope peak at approximately integer multiples of approximately...
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.95.20.11532
更新日期:1998-09-29 00:00:00
abstract::Hypomagnesemia affects insulin resistance and is a risk factor for diabetes mellitus type 2 (DM2) and gestational diabetes mellitus (GDM). Two single nucleotide polymorphisms (SNPs) in the epithelial magnesium channel TRPM6 (V(1393)I, K(1584)E) were predicted to confer susceptibility for DM2. Here, we show using patch...
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.1113811109
更新日期:2012-07-10 00:00:00