Abstract:
:Somatic crossing-over was used in heterozygous Drosophila melanogaster to effect clonal homozygosity for three mutants (h, Hw, ac). In these mutants, one type of process, chaetae, replaces another type, trichomes, in specific patterns on the adult fly. Heterozygous individuals were irradiated at different larval or pupal ages with x-rays and the somatic crossing-over was identified in the adult cuticle by genetically coupled mutants serving as cell markers of chaetae and trichomes. Induction of homozygosis more than 8 hr before puparium formation resulted in autonomous differentiation of the mutant pattern in the homozygous patch of tissue for the three mutants tested; homozygosis induced within 8 hr of puparium formation was not followed by expression of the corresponding genotype. 8 hr before puparium formation, each cell type still has to divide twice before metamorphosis and differentiation. Thus, the genetically conditioned decision of a specific cell to differentiate either a chaeta or a trichome is made during the growth of the wing imaginal disc and is transmitted clonally to descendant cells. Once this decision has been made, subsequent changes in the genotype of the cell or of its daughters are not material to the fate of the cell. We introduce the term "perdurance" to designate the persistence of a cellular developmental fate for several cell generations after the loss of the genetic basis for that cellular development.
journal_name
Proc Natl Acad Sci U S Aauthors
Garcia-Bellido A,Merriam JRdoi
10.1073/pnas.68.9.2222subject
Has Abstractpub_date
1971-09-01 00:00:00pages
2222-6issue
9eissn
0027-8424issn
1091-6490journal_volume
68pub_type
杂志文章abstract::Grasslands cover more than 20% of the Earth's terrestrial surface, and their rise to dominance is one of the most dramatic events of biome evolution in Earth history. Grasses possess two main photosynthetic pathways: the C(3) pathway that is typical of most plants and a specialized C(4) pathway that minimizes photores...
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.0909672107
更新日期:2010-02-09 00:00:00
abstract::Immune responses to several soluble antigens were compared between B6.C-H-2bm12 mutant and wild-type B6 mice by using a lymph node T-cell proliferation assay. B6.C-H-2bm12 mice failed to respond to beef insulin whereas other IA gene-controlled responses, such as response to poly(L-Tyr, L-Glu)--poly(DL-Ala, L-Lys) and ...
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.78.10.6406
更新日期:1981-10-01 00:00:00
abstract::In insulin resistant states such as type 2 diabetes, there is a high demand on the β-cell to synthesize and secrete insulin, which challenges the ability of the endoplasmic reticulum (ER) to synthesize and fold nascent proteins. This creates a state of ER stress that triggers a coordinated program referred to as the 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.1322564111
更新日期:2014-01-21 00:00:00
abstract::T helper 17 (TH17) cells represent a discrete TH cell subset instrumental in the immune response to extracellular bacteria and fungi. However, TH17 cells are considered to be detrimentally involved in autoimmune diseases like multiple sclerosis (MS). In contrast to TH17 cells, regulatory T (Treg) cells were shown to b...
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.1523869113
更新日期:2016-09-06 00:00:00
abstract::Although some important advances in the modeling of sorption and hygrothermal deformations of nanoporous materials such as hydrated cement paste, shale, coal, and some other rocks and soils have already been made, a comprehensive nanoporomechanics theory remains elusive. Here we strive to formulate it based on Gibb's ...
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.1919337117
更新日期:2020-02-18 00:00:00
abstract::The crystal structure of the murine Fab S-20-4 from a protective anti-cholera Ab specific for the lipopolysaccharide Ag of the Ogawa serotype has been determined in its unliganded form and in complex with synthetic fragments of the Ogawa O-specific polysaccharide (O-SP). The upstream terminal O-SP monosaccharide is sh...
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.060022997
更新日期:2000-07-18 00:00:00
abstract::Understanding plant metabolism as an integrated system is essential for metabolic engineering aimed at the effective production of compounds useful to human life and the global environment. The "omics" approach integrates transcriptome and metabolome data into a single data set and can lead to the identification of un...
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.0611629104
更新日期:2007-04-10 00:00:00
abstract::Dense granules of platelets contain a high content of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A). We have previously demonstrated an antithrombotic effect of this compound in a live rabbit model. In the present study we find that certain synthetic Ap4A analogues are superior to Ap4A in inhibiting ADP-induced aggr...
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.89.6.2370
更新日期:1992-03-15 00:00:00
abstract::The structure of promoter chromatin determines the ability of transcription factors (TFs) to bind to DNA and therefore has a profound effect on the expression levels of genes. However, the role of spontaneous nucleosome movements in this process is not fully understood. Here, we developed a single-molecule optical twe...
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:2019-06-18 00:00:00
abstract::After more than two decades of study, many fundamental questions remain unanswered about the dynamics of glass-forming materials confined to thin films. Experiments and simulations indicate that free interfaces enhance dynamics over length scales larger than molecular sizes, and this effect strengthens at lower temper...
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.2006703117
更新日期:2020-10-13 00:00:00
abstract::From our current understanding of the genetic basis of development and pattern formation in Drosophila and vertebrates it is commonly thought that clusters of Hox genes sculpt the morphology of animals in specific body regions. Based on Hox gene conservation throughout the animal kingdom it is proposed that these 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.95.6.3030
更新日期:1998-03-17 00:00:00
abstract::Cleavage of the hemagglutinin (HA) in tissue culture systems has been correlated with virulence of avian influenza viruses. To examine the structural requirements for cleavage of the HA, the HA gene from a virulent H5 influenza virus was expressed in mammalian cells (CV-1), and the cleavage site of the HA was explored...
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.85.2.324
更新日期:1988-01-01 00:00:00
abstract::The thymus provides multiple microenvironments that are essential for the development and repertoire selection of T lymphocytes. The thymic cortex induces the generation and positive selection of T lymphocytes, whereas the thymic medulla establishes self-tolerance among the positively selected T lymphocytes. Cortical ...
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.1301799110
更新日期:2013-06-11 00:00:00
abstract::The role of spliced leader RNA (SL RNA) in trans-splicing in Caenorhabditis elegans has been studied through a combination of in vitro mutagenesis and in vivo complementation of rrs-1 mutant nematodes, which lack endogenous SL1 RNA. Three classes of mutant SL1 RNAs have been found-those that rescue the lethal phenotyp...
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.95.8.4235
更新日期:1998-04-14 00:00:00
abstract::In the cytoplasm of well-spread cultured normal fibroblasts, actin is organized into a network of cables that run the length of the cell just inside the adherent cell membrane. A diffuse matrix replaces the cables in fibroblasts that have become tumorigenic as a result of oncogenic transformation. We have found a simi...
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.74.7.3019
更新日期:1977-07-01 00:00:00
abstract::New approaches to the study of early hominin diets have refreshed interest in how and when our diets diverged from those of other African apes. A trend toward significant consumption of C4 foods in hominins after this divergence has emerged as a landmark event in human evolution, with direct evidence provided by stabl...
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.2006221117
更新日期:2020-09-08 00:00:00
abstract::The intracellular levels of many proteins are regulated by ubiquitin-dependent proteolysis. One of the best-characterized enzymes that catalyzes the attachment of ubiquitin to proteins is a ubiquitin ligase complex, Skp1-Cullin-F box complex containing Hrt1 (SCF). We sought to artificially target a protein to the SCF ...
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.141230798
更新日期:2001-07-17 00:00:00
abstract::A major problem facing the effective treatment of patients with cancer is how to get the specific antitumor agent into every tumor cell. In this report we describe the use of a strategy that, by using retroviral vectors encoding a truncated human CD5 cDNA, allows the selection of only the infected cells, and we show 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.94.24.13239
更新日期:1997-11-25 00:00:00
abstract::To generate antibodies with different effector functions, B cells undergo Immunoglobulin Heavy Chain (IgH) class switch recombination (CSR). The ligation step of CSR is usually mediated by the classical nonhomologous end-joining (cNHEJ) pathway. In cNHEJ-deficient cells, a remarkable ∼25% of CSR can be achieved by the...
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:2020-10-13 00:00:00
abstract::Public responses where identical T cell receptors (TCRs) are clonally dominant and shared between different individuals are a common characteristic of CD8(+) T cell-mediated immunity. Focusing on TCR sharing, we analyzed approximately 3,400 TCR beta chains (TCRbetas) from mouse CD8(+) T cells responding to the influen...
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.0608907103
更新日期:2006-12-05 00:00:00
abstract::Mobile ectothermic animals can control their body temperatures by selecting specific thermal conditions in the environment, but embryos--trapped within an immobile egg and lacking locomotor structures--have been assumed to lack that ability. Falsifying that assumption, our experimental studies show that even early sta...
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.1102965108
更新日期:2011-06-07 00:00:00
abstract::Molecular agitation more rapid than thermal Brownian motion is reported for cellular environments, motor proteins, synthetic molecular motors, enzymes, and common chemical reactions, yet that chemical activity coupled to molecular motion contrasts with generations of accumulated knowledge about diffusion at equilibriu...
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.2019810117
更新日期:2020-11-24 00:00:00
abstract::Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tool...
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.1703084114
更新日期:2017-08-29 00:00:00
abstract::The signals required for rapid internalization of the bovine cation-dependent mannose 6-phosphate receptor have been localized to two distinct regions of the 67-amino acid cytoplasmic domain. One signal includes phenylalanine 13 and phenylalanine 18, while the other involves tyrosine 45. The former signal is more pote...
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.87.24.10010
更新日期:1990-12-01 00:00:00
abstract::Necessary conditions are derived for a spherical vortex in a perfect fluid to be stationary in the case when the velocities depend on a single surface harmonic. The motion is indeterminate unless an additional condition is imposed. In the case when this condition is incompressibility, the equations are solved, yieldin...
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.69.9.2460
更新日期:1972-09-01 00:00:00
abstract::MicroRNAs (miRNAs) are small 19- to 24-nt noncoding RNAs that have the capacity to regulate fundamental biological processes essential for cancer initiation and progression. In cancer, miRNAs may function as oncogenes or tumor suppressors. Here, we conducted global profiling for miRNAs in a cohort of stage 1 nonsmall ...
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.1307107110
更新日期:2013-09-10 00:00:00
abstract::The integrity of the endothelial barrier between circulating blood and tissue is important for blood vessel function and, ultimately, for organ homeostasis. Here, we developed a vessel-on-a-chip with perfused endothelialized channels lined with human bone marrow stromal cells, which adopt a mural cell-like phenotype t...
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:2017-08-15 00:00:00
abstract::The conservation of endangered fish is of critical importance. Cryobanking could provide an effective backup measure for use in conjunction with the conservation of natural populations; however, methodology for cryopreservation of fish eggs and embryos has not yet been developed. The present study established a method...
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.1218468110
更新日期:2013-01-29 00:00:00
abstract::After the emergence of pandemic influenza viruses in 1957, 1968, and 2009, existing seasonal viruses were observed to be replaced in the human population by the novel pandemic strains. We have previously hypothesized that the replacement of seasonal strains was mediated, in part, by a population-scale boost in antibod...
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.1200039109
更新日期:2012-02-14 00:00:00
abstract::Chicken erythrocyte nuclei have been labeled in the active regions of the chromosome by using the nick translation reaction. In this procedure, accessible areas of the genome are preferentially nicked by the action of pancreatic DNase I and subsequently labeled by using DNA polymerase I from Escherichia coli. These nu...
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.77.4.1787
更新日期:1980-04-01 00:00:00