Abstract:
:Tyr-SV40E transgenic mice are susceptible to melanoma due to simian virus 40 oncogenic sequences specifically expressed in pigment cells. Skin melanomas form relatively late. Therefore, melanocyte cell lines have been established from very young transgenic animals, when they showed no skin lesions, so that the spontaneous and gradual progress of the cells toward tumorigenesis could be characterized under culture conditions in which wild-type cells of the same inbred strain remain untransformed. Melanocytes of an in vitro transgenic line were irradiated with very low intensities of ultraviolet B (UVB) (280- to 320-nm wavelength) light at culture passages when the cells had not achieved anchorage independence. After a single exposure to 0.7 mJ/cm2 of UVB radiation, the cells became anchorage independent and formed foci at confluence; however, cells propagated from the foci were not tumorigenic. After one exposure to 1.75 mJ/cm2, more numerous and larger foci resulted, and the cells grown from them yielded malignant melanomas in graft hosts. Wild-type melanocytes were not transformed at these UVB doses. At least two genetic changes contributing to malignant conversion--in addition to the initiating effect of the transgene--are likely to have occurred, one change leading to anchorage independence and another to further progress toward malignancy. Cells at these stages provide an opportunity to isolate the relevant genes and identify any molecular defects attributable to UVB. Tumorigenesis after a very low UVB dose in cells where an initiating stimulus is already present suggests that some other stimulus, such as a gene or a carcinogen, might lead to melanoma in conjunction with exposure to relatively little UVB.
journal_name
Proc Natl Acad Sci U S Aauthors
Larue L,Dougherty N,Mintz Bdoi
10.1073/pnas.89.20.9534keywords:
subject
Has Abstractpub_date
1992-10-15 00:00:00pages
9534-8issue
20eissn
0027-8424issn
1091-6490journal_volume
89pub_type
杂志文章abstract::The objective of this study was to determine whether the vascular smooth muscle contractile effect of NG-methyl-L-arginine (NMA) is endothelium dependent and attributed to a decline in smooth muscle levels of cyclic GMP. Vascular smooth muscle levels of cyclic GMP are severalfold greater in endothelium-intact than 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.87.12.4430
更新日期:1990-06-01 00:00:00
abstract::Interphotoreceptor retinoid-binding protein (IRBP) has been hypothesized to function as an intercellular shuttle in the vertebrate eye, serving to transport retinoids between the retinal pigment epithelium (RPE) and photoreceptors in the process by which visual pigment is regenerated after photolysis. This hypothesis ...
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.87.17.6907
更新日期:1990-09-01 00:00:00
abstract::X-ray studies on human insulins prepared by semisynthetic and biosynthetic methods have recently been undertaken. Human insulin differs from porcine insulin only at the COOH terminus of the B-chain. The present study reports the crystal structure of 4-zinc human insulin, which is used clinically as a slow-acting prepa...
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.81.22.7093
更新日期:1984-11-01 00:00:00
abstract::The amino acid sequence of rabbit skeletal muscle heat-stable inhibitor of the cAMP-dependent protein kinase has been determined by microsequencing techniques. Proof of the structure involved a series of nonoverlapping tryptic fragments for primary identification of 86% of the amino acids. Complementary fragments gene...
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.82.17.5732
更新日期:1985-09-01 00:00:00
abstract::Inhibitory gamma-aminobutyric acid-mediated synaptic currents were studied in dissociated primary cultures of neonatal rat cortex with the whole-cell patch-clamp technique. Immunocytochemical staining of the cultures showed the presence of a large number of glutamic acid decarboxylase-containing neurons, and electrica...
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.83.23.9269
更新日期:1986-12-01 00:00:00
abstract::Temporal integration in visual perception is thought to occur within cycles of occipital alpha-band (8-12 Hz) oscillations. Successive stimuli may be integrated when they fall within the same alpha cycle and segregated for different alpha cycles. Consequently, the speed of alpha oscillations correlates with the tempor...
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.1713318115
更新日期:2018-02-06 00:00:00
abstract::Calmodulin (CaM) is a second messenger protein that has evolved to bind tightly to a variety of targets and, as such, exhibits low binding specificity. We redesigned CaM by using a computational protein design algorithm to improve its binding specificity for one of its targets, smooth muscle myosin light chain kinase ...
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.2234277100
更新日期:2003-11-11 00:00:00
abstract::We study the dynamic network of e-mail traffic and find that it develops self-organized coherent structures similar to those appearing in many nonlinear dynamic systems. Such structures are uncovered by a general information theoretic approach to dynamic networks based on the analysis of synchronization among trios 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.0405728101
更新日期:2004-10-05 00:00:00
abstract::The accuracy of the 3'-end processing by cleavage and polyadenylation is essential for mRNA biogenesis and transcription termination. In yeast, two poorly conserved neighboring elements upstream of cleavage sites are important for accuracy and efficiency of this process. These two RNA sequences are recognized by the 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.1214102110
更新日期:2012-12-26 00:00:00
abstract::Saccharopolyspora erythraea makes erythromycin, an antibiotic commonly used in human medicine. Unusually, the erythromycin biosynthetic (ery) cluster lacks a pathway-specific regulatory gene. We isolated a transcriptional regulator of the ery biosynthetic genes from S. erythraea and found that this protein appears 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.0803622105
更新日期:2008-08-12 00:00:00
abstract::Emotional responses, such as fear and anxiety, are fundamentally important behavioral phenomena with strong fitness components in most animal species. Anxiety-related disorders continue to represent a major unmet medical need in our society, mostly because we still do not fully understand the mechanisms of these disea...
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.1707663115
更新日期:2018-01-30 00:00:00
abstract::Chorismate mutase acts at the first branch-point of aromatic amino acid biosynthesis and catalyzes the conversion of chorismate to prephenate. The results of molecular dynamics simulations of the substrate in solution and in the active site of chorismate mutase are reported. Two nonreactive conformers of chorismate ar...
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.141230998
更新日期:2001-07-31 00:00:00
abstract::Initiation of adenovirus DNA replication in vitro occurs on a linearized plasmid DNA containing 3,327 base pairs of the adenovirus terminal sequence. Various deletions have been constructed in the plasmid DNA and their template activities examined. Deletions from an internal restriction enzyme cleavage site that retai...
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.80.21.6446
更新日期:1983-11-01 00:00:00
abstract::Multiple biological processes involve the stretching of nucleic acids (NAs). Stretching forces induce local changes in the molecule structure, inhibiting or promoting the binding of proteins, which ultimately affects their functionality. Understanding how a force induces changes in the structure of NAs at the atomic l...
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.1705642114
更新日期:2017-07-03 00:00:00
abstract::Reconstructing the origin and early evolutionary history of anthropoid primates (monkeys, apes, and humans) is a current focus of paleoprimatology. Although earlier hypotheses frequently supported an African origin for anthropoids, recent discoveries of older and phylogenetically more basal fossils in China and Myanma...
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.1200644109
更新日期:2012-06-26 00:00:00
abstract::Neutrophils are important effector cells in immunity to microorganisms, particularly bacteria. Here, we show that the process of neutrophil apoptosis is delayed in several inflammatory diseases, suggesting that this phenomenon may represent a general feature contributing to the development of neutrophilia, and, theref...
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.96.23.13330
更新日期:1999-11-09 00:00:00
abstract::Human PC4 and the yeast ortholog Sub1 have multiple functions in RNA polymerase II transcription. Genome-wide mapping revealed that Sub1 is present on Pol III-transcribed genes. Sub1 was found to interact with components of the Pol III transcription system and to stimulate the initiation and reinitiation steps in a sy...
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.0900162106
更新日期:2009-08-25 00:00:00
abstract::The fungus, Phycomyces blakesleeanus, shows many well-defined responses to a number of external stimuli. Genetic analysis shows that at least eight genes are involved in Phycomyces sensory transduction. As a first step toward the molecular analysis of these genes and their products, we have developed a transformation ...
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.83.19.7344
更新日期:1986-10-01 00:00:00
abstract::Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to 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.1600362113
更新日期:2016-08-09 00:00:00
abstract::Thioredoxins are small multifunctional redox active proteins widely if not universally distributed among living organisms. In chloroplasts, two types of thioredoxins (f and m) coexist and play central roles in regulating enzyme activity. Reduction of thioredoxins in chloroplasts is catalyzed by an iron-sulfur disulfid...
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.232703799
更新日期:2003-01-07 00:00:00
abstract::Metabolism of [3-13C]alanine in the presence and absence of beta-hydroxybutyrate or ethanol has been followed at 25 degrees C by 13C NMR at 90.5 MHz in primary hepatocytes from untreated rats and rats treated with triiodothyronine and not allowed to eat for 24 hr. The phosphoenolpyruvate/pyruvate futile cycle was foll...
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.78.1.60
更新日期:1981-01-01 00:00:00
abstract::Many insects are dependent on bacterial symbionts that provide essential nutrients (ex. aphid-Buchnera and tsetse-Wiglesworthia associations), wherein the symbionts are harbored in specific cells called bacteriocytes that constitute a symbiotic organ bacteriome. Facultative and parasitic bacterial symbionts like Wolba...
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.0911476107
更新日期:2010-01-12 00:00:00
abstract::Two precursors to Chinook salmon (Oncorhynchus tshawytscha) melanin-concentrating hormone, an important factor in teleosts involved in the control of skin pigmentation and stress responsiveness, have been identified from DNA sequence analysis. Both precursors encode proteins of 132 amino acids and they share 107/132 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.86.11.4292
更新日期:1989-06-01 00:00:00
abstract::Modern European genetic structure demonstrates strong correlations with geography, while genetic analysis of prehistoric humans has indicated at least two major waves of immigration from outside the continent during periods of cultural change. However, population-level genome data that could shed light on the demograp...
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.1719880115
更新日期:2018-03-27 00:00:00
abstract::Mouse blastocyst functions have been shown to be disrupted by in vitro exposure to N-methyl-N-nitrosourea (MeNU). After exposure, the chemically treated blastocysts were transferred to the uteri of pseudopregnant surrogate mothers. Implantation rate and birth rate have been shown previously to decrease in a concentrat...
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.82.24.8757
更新日期:1985-12-01 00:00:00
abstract::A model is presented for age-specific selection on the genotypes in a population. Each genotype is assigned a life table that specifies the viability and fecundity of its age classes. Breeding and reproduction occur at regular intervals, and generations overlap. Examples were generated on a digital computer. Gene freq...
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.66.3.780
更新日期:1970-07-01 00:00:00
abstract::Upon stimulation with anti-CD3, suppressor T-cell (Ts) hybridomas and homologous transfectants of T-cell receptor a (TCRalpha) cDNA in the T-cell hybridoma formed a 55-kDa TCRalpha chain derivative that bound both the monoclonal anti-TCRalpha chain and polyclonal antibodies against glycosylation inhibiting factor (GIF...
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.93.14.7207
更新日期:1996-07-09 00:00:00
abstract::Defining the processes of autoimmune attack of tissues is important for inhibiting continued tissue destruction. In type 1 diabetes, it is not known how cytotoxic effector T cell responses evolve over time in the pancreatic islets targeted for destruction. We used two-photon microscopy of live, intact, individual isle...
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.1322193111
更新日期:2014-06-24 00:00:00
abstract::HLA-I molecules play a central role in antigen presentation. They typically bind 9- to 12-mer peptides, and their canonical binding mode involves anchor residues at the second and last positions of their ligands. To investigate potential noncanonical binding modes, we collected in-depth and accurate HLA peptidomics da...
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.1717277115
更新日期:2018-05-15 00:00:00
abstract::Cloned 3.18 kilobase fragments of Xenopus laevis DNA containing genes for tRNAMet1 and for at least one other 4S RNA species are transcribed rapidly after their injection into the nucleus of X. laevis oocytes. The newly synthesized RNA can be resolved by gel electrophoresis into a few predominant 4S RNA species and 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.75.3.1176
更新日期:1978-03-01 00:00:00