Abstract:
:Animals and plants use modified cell cycles to achieve particular developmental strategies. In one common example, most animals and plants have tissues in which the cells become polyploid or polytene by means of an S-G cycle, but the mechanism by which mitosis is inhibited in the endo cycle is not understood. The Drosophila morula (mr) gene regulates variant cell cycles, because in addition to disrupting the archetypal cycle (G1-S-G2-M), mr mutations affect the rapid embryonic (S-M) divisions as well as the endo cycle (S-G) that produces polyploid cells. In dividing cells mr mutations cause a metaphase arrest, and endo cycling nurse cells inappropriately reenter mitosis in mr mutants. We show mr encodes the APC2 subunit of the anaphase promoting complex/cyclosome. This finding demonstrates that anaphase promoting complex/cyclosome is required not only in proliferating cells but also to block mitosis in some endo cycles. The mr mutants further indicate that transient mitotic functions in endo cycles change chromosome morphology from polytene to polyploid.
journal_name
Proc Natl Acad Sci U S Aauthors
Kashevsky H,Wallace JA,Reed BH,Lai C,Hayashi-Hagihara A,Orr-Weaver TLdoi
10.1073/pnas.172391099keywords:
subject
Has Abstractpub_date
2002-08-20 00:00:00pages
11217-22issue
17eissn
0027-8424issn
1091-6490pii
172391099journal_volume
99pub_type
杂志文章abstract::The WWOX gene is a recently cloned tumor suppressor gene that spans the FRA16D fragile region. Wwox protein contains two WW domains that are generally known to mediate protein-protein interaction. Here we show that Wwox physically interacts via its first WW domain with the p53 homolog, p73. The tyrosine kinase, Src, p...
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.0400805101
更新日期:2004-03-30 00:00:00
abstract::Many cortical neurons combine the information ascending and descending the cortical hierarchy. In the classical view, this information is combined nonlinearly to give rise to a single firing-rate output, which collapses all input streams into one. We analyze the extent to which neurons can simultaneously represent mul...
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.1720995115
更新日期:2018-07-03 00:00:00
abstract::Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact nanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two fam...
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.0909616107
更新日期:2010-06-29 00:00:00
abstract::Signaling by a variety of receptor and nonreceptor tyrosine kinases is mediated by Ras, a membrane-associated GTPase. Expression of v-Src, a transforming nonreceptor tyrosine kinase, results in Ras activation, and inhibition of Ras function in NIH 3T3 cells suppresses transformation by v-Src, indicating that in these ...
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.94.7.3028
更新日期:1997-04-01 00:00:00
abstract::DNA methylation may be a component of a multilevel control mechanism that regulates eukaryotic gene expression. We used synthetic oligonucleotides to investigate the effect of cytosine methylation on the binding of the transcription factor Sp1 to its target sequence (a G + C-rich sequence known as a "GC box"). Concate...
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.85.7.2066
更新日期:1988-04-01 00:00:00
abstract::The TCR is an alpha beta heterodimer, a part of the multimeric structure through which physiological T-cell activation occurs. The expression of TCR alpha chain is greatly diminished in a beta-chain-deficient mutant Jurkat cell line (J.RT3-T3.5). The relationship between the expression of the TCR alpha and beta chains...
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.92.9.3712
更新日期:1995-04-25 00:00:00
abstract::Antigen stimulation of mast cells via FcepsilonRI, the high-affinity receptor for IgE, triggers a signaling cascade that requires Ca(2+) mobilization for exocytosis of secretory granules during an allergic response. This study investigates critical signaling components by using mutant RBL mast cells that are defective...
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.98.3.1154
更新日期:2001-01-30 00:00:00
abstract::Seasonal epidemics and periodic worldwide pandemics caused by influenza A viruses are of continuous concern. The viral nonstructural (NS1) protein is a multifunctional virulence factor that antagonizes several host innate immune defenses during infection. NS1 also directly stimulates class IA phosphoinositide 3-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.0910715107
更新日期:2010-02-02 00:00:00
abstract::Chemokines play a key role in inflammation. They are expressed not only in neuroinflammatory conditions, but also constitutively by different cell types, including neurons in the normal brain, suggesting that they may act as modulators of neuronal functions. Here, we investigated a possible neuroendocrine role of the ...
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.0602620103
更新日期:2006-05-23 00:00:00
abstract::To investigate the evolution of the mammalian sex chromosomes, we have compared the gene content of the X chromosomes in the mammalian groups most distantly related to man (marsupials and monotremes). Previous work established that genes on the long arm of the human X chromosome are conserved on the X chromosomes in 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.88.24.11256
更新日期:1991-12-15 00:00:00
abstract::Control of iron homeostasis is essential for healthy central nervous system function: iron deficiency is associated with cognitive impairment, yet iron overload is thought to promote neurodegenerative diseases. Specific genetic markers have been previously identified that influence levels of transferrin, the protein 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.1105543109
更新日期:2012-04-03 00:00:00
abstract::The temporal and spatial patterns of floral determination in cultured internode segments of Nicotiana tabacum L. cv. Wisconsin 38 were investigated. Segments from internodes, when cultured on hormone-free medium, either produced some de novo floral shoots or produced only vegetative shoots. Segments that produced some...
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.84.9.2790
更新日期:1987-05-01 00:00:00
abstract::For several decades, research into the mechanisms of genetic recombination proceeded without a complete understanding of its cellular function or its place in DNA metabolism. Many lines of research recently have coalesced to reveal a thorough integration of most aspects of DNA metabolism, including recombination. In b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.131004998
更新日期:2001-07-17 00:00:00
abstract::We have previously described how T and natural killer (NK) lineage commitment proceeds from common T/NK progenitors (p-T/NK) in the murine fetal thymus (FT), with the use of a clonal assay system capable of discriminating p-T/NK from unipotent T or NK lineage-committed progenitors (p-T and p-NK, respectively). The mol...
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.091537598
更新日期:2001-04-24 00:00:00
abstract::Processing of a protein antigen into fragments is believed to be a prerequisite for its presentation by the antigen-presenting cell to the T cell. This model would predict that, in oligomeric proteins, T cells prepared with specificity for regions that are buried within subunit association surfaces should recognize th...
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.86.17.6729
更新日期:1989-09-01 00:00:00
abstract::Benthic foraminifers inhabit a wide range of aquatic environments including open marine, brackish, and freshwater environments. Here we show that several different and diverse foraminiferal groups (miliolids, rotaliids, textulariids) and Gromia, another taxon also belonging to Rhizaria, accumulate and respire nitrates...
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.0908440107
更新日期:2010-01-19 00:00:00
abstract::APOBEC3 (A3) genes are members of the AID/APOBEC gene family that are found exclusively in mammals. A3 genes encode antiviral proteins that restrict the replication of retroviruses by inducing G-to-A mutations in their genomes and have undergone extensive amplification and diversification during mammalian evolution. 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.1914183116
更新日期:2020-01-07 00:00:00
abstract::DsRed, a brilliantly red fluorescent protein, was recently cloned from Discosoma coral by homology to the green fluorescent protein (GFP) from the jellyfish Aequorea. A core question in the biochemistry of DsRed is the mechanism by which the GFP-like 475-nm excitation and 500-nm emission maxima of immature DsRed are 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.97.22.11990
更新日期:2000-10-24 00:00:00
abstract::In contrast with speciation in terrestrial organisms, marine plankton frequently display gradual morphological change without lineage division (e.g., phyletic gradualism or gradual evolution), which has raised the possibility that a different mode of evolution dominates within pelagic environments. Here, we reexamine ...
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.0902887106
更新日期:2009-12-15 00:00:00
abstract::Increasing evidence suggests that amyloid polymorphism gives rise to different strains of amyloids with distinct toxicities and pathology-spreading properties. Validating this hypothesis is challenging due to a lack of tools and methods that allow for the direct characterization of amyloid polymorphism in hydrated 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.1916176117
更新日期:2020-03-24 00:00:00
abstract::A structural gene for the alpha-subunit of RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase; EC 2.7.7.6) has been identified and mapped between spcA and trkA, near 64 min on the E. coli chromosome. It appears to be coordinately expressed and possibly cotranscribed with the genes for ribosomal proteins...
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.72.12.5036
更新日期:1975-12-01 00:00:00
abstract::The λ exonuclease is an ATP-independent enzyme that binds to dsDNA ends and processively digests the 5'-ended strand to form 5' mononucleotides and a long 3' overhang. The crystal structure of λ exonuclease revealed a toroidal homotrimer with a central funnel-shaped channel for tracking along the DNA, and a mechanism ...
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.1103467108
更新日期:2011-07-19 00:00:00
abstract::We present a proposition, the "poly(L-alanine) hypothesis," which asserts that the native backbone geometry for any polypeptide or protein of M residues has a closely mimicking, mechanically stable, image in poly(L-alanine) of the same number of residues. Using a molecular mechanics force field to represent the releva...
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.89.23.11513
更新日期:1992-12-01 00:00:00
abstract::We show that it is possible to direct particles entrained in a fluid along trajectories much like rays of light in classical optics. A microstructured, asymmetric post array forms the core hydrodynamic element and is used as a building block to construct microfluidic metamaterials and to demonstrate refractive, focusi...
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.0712398105
更新日期:2008-05-27 00:00:00
abstract::Let G be a reductive algebraic group and let B be an affine variety with an algebraic action of G. Everything is defined over the field C of complex numbers. Consider the trivial G-vector bundle B x S = S over B where S is a G-module. From the endomorphism ring R of the G-vector bundle S a construction of G-vector bun...
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.88.20.9061
更新日期:1991-10-15 00:00:00
abstract::Multiple studies have established that microRNAs (miRNAs) are involved in the initiation and progression of cancer. Notably, miR-155 is one of the most overexpressed miRNAs in several solid and hematological malignancies. Ectopic miR-155 expression in mice B cells (Eμ-miR-155 transgenic mice) has been shown to induce ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,meta分析
doi:10.1073/pnas.1213764109
更新日期:2012-12-04 00:00:00
abstract::A polypeptide was purified from rat hypothalamic extracts on the basis of its high intrinsic activity to release corticotropin (ACTH) from cultured rat anterior pituitary cells and its immunoactivity in a radioimmunoassay directed against the NH2 terminus (residues 4-20) of ovine hypothalamic corticotropin-releasing f...
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.80.15.4851
更新日期:1983-08-01 00:00:00
abstract::In this paper I review the ways in which the glassy state is obtained both in nature and in materials science and highlight a "new twist"--the recent recognition of polymorphism within the glassy state. The formation of glass by continuous cooling (viscous slowdown) is then examined, the strong/fragile liquids classif...
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.92.15.6675
更新日期:1995-07-18 00:00:00
abstract::Skin wound infections are a significant health problem, and antibiotic resistance is on the rise. Mast cells (MCs) have been shown to contribute to host-defense responses in certain bacterial infections, but their role in skin wound superinfection is unknown. We subjected 2 MC-deficient mouse strains to Pseudomonas ae...
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.1908816116
更新日期:2019-10-08 00:00:00
abstract::In an autoshaping experiment, food-deprived pigeons pecked rapidly at a moving dot that preceded the delivery of food. When the moving dot and food were no longer correlated, the rate of pecking dropped nearly to zero. When, subsequently, no food was given, pecking reappeared at a high rate (nearly 200 pecks per min f...
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.77.10.6251
更新日期:1980-10-01 00:00:00