Abstract:
:Myofibril formation was visualized in cultured live cardiomyocytes that were transfected with plasmids expressing green fluorescent protein (GFP) linked to the Z-band protein, alpha-actinin. The expression of this fluorescent protein provided an in vivo label for structures containing alpha-actinin. The GFP-alpha-actinin fusion protein was incorporated into Z-bands, intercalated discs, and attachment plaques, as well as into the punctate aggregates, or Z-bodies, that are thought to be the precursors of Z-bands. Observations of live cells over several days in culture permitted us to test aspects of several theories of myofibril assembly that had been proposed previously based on the study of fixed cells. Fine fibrils, called premyofibrils, that formed de novo at the spreading edges of cardiomyocytes, contained punctate concentrations of alpha-actinin, termed Z-bodies. The punctate Z-bodies grew and aligned with Z-bodies in adjacent fibrils. With increasing time, adjacent fibrils and Z-bodies appeared to fuse and form mature myofibrils and Z-bands in cytoplasmic regions where the linear arrays of Z-bodies had been. These new myofibrils became aligned with existing myofibrils at their Z-bands to form myofibrils that spanned the length of the spread cell. These results are consistent with a model that postulates that the fibrils that form de novo near the cell membrane are premyofibrils-i.e., the precursors of mature myofibrils.
journal_name
Proc Natl Acad Sci U S Aauthors
Dabiri GA,Turnacioglu KK,Sanger JM,Sanger JWdoi
10.1073/pnas.94.17.9493subject
Has Abstractpub_date
1997-08-19 00:00:00pages
9493-8issue
17eissn
0027-8424issn
1091-6490journal_volume
94pub_type
杂志文章abstract::Synechococcus elongatus PCC 7942 is a genetically tractable model cyanobacterium that has been engineered to produce industrially relevant biomolecules and is the best-studied model for a prokaryotic circadian clock. However, the organism is commonly grown in continuous light in the laboratory, and data on metabolic 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.1504576112
更新日期:2015-04-14 00:00:00
abstract::Transcriptional repression via methylation of histone H3 lysine 27 (H3K27) by the polycomb repressive complex 2 (PRC2) is conserved in higher eukaryotes. The Arabidopsis PRC2 controls homeotic gene expression, flowering time, and gene imprinting. Although downstream target genes and the regulatory mechanism of PRC2 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.1104232108
更新日期:2011-05-10 00:00:00
abstract::Clostridium kluyveri grown in the presence of 1 muM Na2(75)SeO3 produces a thiolase that copurifies with 75Se. Based on several criteria, the selenium moiety in this protein is selenomethionine. The 75Se-labeled amino acid in acid hydrolysates of the radioactive protein cochromatographed with authentic selenomethionin...
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.79.16.4912
更新日期:1982-08-01 00:00:00
abstract::The operon model was proposed by Jacob and Monod in 1961 to explain the regulation of enzyme synthesis in bacteria. The model requires two genetic elements: a locus i which directs the synthesis of a repressor, and a locus called the operon which contains an operator gene and associated structural genes. The repressor...
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.62.2.550
更新日期:1969-02-01 00:00:00
abstract::Spectral methods are of fundamental importance in statistics and machine learning, because they underlie algorithms from classical principal components analysis to more recent approaches that exploit manifold structure. In most cases, the core technical problem can be reduced to computing a low-rank approximation to 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.0810600105
更新日期:2009-01-13 00:00:00
abstract::In Gram-negative bacteria, the outer membrane contains primarily β-barrel transmembrane proteins and lipoproteins. The insertion and assembly of β-barrel outer-membrane proteins (OMPs) is mediated by the β-barrel assembly machinery (BAM) complex, the core component of which is the 16-stranded transmembrane β-barrel Ba...
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.1722530115
更新日期:2018-08-21 00:00:00
abstract::Poly(A)-containing RNA was isolated from ovaries of Xenopus laevis laevis and Triturus cristatus carnifex and used as a template for the synthesis of radioactive complementary DNA with RNA-dependent DNA polymerase. When annealed with an excess of homologous DNA, the complementary DNA is rendered double-stranded with k...
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.71.9.3746
更新日期:1974-09-01 00:00:00
abstract::Molecular oxygen (O(2)) began to accumulate in the atmosphere and surface ocean ca. 2,400 million years ago (Ma), but the persistent oxygenation of water masses throughout the oceans developed much later, perhaps beginning as recently as 580-550 Ma. For much of the intervening interval, moderately oxic surface waters ...
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.0909248106
更新日期:2009-10-06 00:00:00
abstract::Four monoclonal anti-parathyroid antibodies were generated after immunization of mice with intact cells from human parathyroid tissue. All four monoclonal antibodies reacted in immunohistochemistry with structures present on parathyroid epithelial cells and proximal-tubule cells of the kidney but were unreactive with ...
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.84.9.2990
更新日期:1987-05-01 00:00:00
abstract::Cofilin-actin rods are inclusion-like structures that are induced by certain chemical or physical stresses in cultured cells, and the rods formed in neurons are thought to be associated with neurodegeneration. Here, we cloned an Aplysia cofilin homolog and overexpressed it in cultured neurons. Overexpressed cofilin fo...
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.0507675102
更新日期:2005-11-01 00:00:00
abstract::Fluoride activation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] is significantly enhanced (2 to 5 times) by a protein factor isolated from rat brain. The fluoride-dependent adenylate cyclase stimulator (FCS) is nondialyzable, trypsin-labile, and stable at 90 degrees C for 10 min. FCS stimula...
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.77.8.4628
更新日期:1980-08-01 00:00:00
abstract::Measured by ultra-slow scanning calorimetry and isothermal circular dichroism, human lung collagen monomers denature at 37 degrees C within a couple of days. Their unfolding rate decreases exponentially at lower temperature, but complete unfolding is observed even below 36 degrees C. Refolding of full-length, native c...
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.032307099
更新日期:2002-02-05 00:00:00
abstract::Ski8p is implicated in degradation of non-poly(A) and double-stranded RNA, and in meiotic DNA recombination. We have identified the Sordaria macrospora SKI8 gene. Ski8p is cytoplasmically localized in all vegetative and sexual cycle cells, and is nuclear localized, specifically in early-mid-meiotic prophase, in 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.2034282100
更新日期:2003-10-28 00:00:00
abstract::The Kitaev model with an applied magnetic field in the [Formula: see text] direction shows two transitions: from a nonabelian gapped quantum spin liquid (QSL) to a gapless QSL at [Formula: see text] and a second transition at a higher field [Formula: see text] to a gapped partially polarized phase, where K is the stre...
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.1821406116
更新日期:2019-06-18 00:00:00
abstract::With Manduca sexta as a model system, we analyzed how natural odor mixtures that are most effective in eliciting flight and foraging behaviors are encoded in the primary olfactory center in the brain, the antennal lobe. We used gas chromatography coupled with multiunit neural-ensemble recording to identify key odorant...
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.0910592106
更新日期:2009-11-17 00:00:00
abstract::Estimation of evolutionary distances has always been a major issue in the study of molecular evolution because evolutionary distances are required for estimating the rate of evolution in a gene, the divergence dates between genes or organisms, and the relationships among genes or organisms. Other closely related issue...
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.95.11.5899
更新日期:1998-05-26 00:00:00
abstract::Studies by several investigators have shown that 12-0-tetradecanoylphorbol-13-acetate (TPA) is an extraordinarily potent stimulator of differentiation of cultured human promyelocytic leukemia cells in vitro. In the present study, TPA was administered to humans by i.v. infusion without irreversible toxicity, and it was...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 临床试验,杂志文章
doi:10.1073/pnas.95.9.5357
更新日期:1998-04-28 00:00:00
abstract::We have previously reported the cloning, sequencing, and partial characterization of Kid-1, a zinc finger-encoding cDNA from the rat kidney. The Kid-1 protein and approximately one-third of all other zinc finger proteins contain a highly conserved region of approximately 75 amino acids at their NH2 terminus named Krüp...
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.91.10.4514
更新日期:1994-05-10 00:00:00
abstract::Without a fully developed initial segment, the most proximal region of the epididymis, male infertility results. Therefore, it is important to understand the development and regulation of this crucial region. In addition to distinctively high activity levels of the components of the ERK pathway, which are essential fo...
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.1413186112
更新日期:2014-12-30 00:00:00
abstract::As a direct simulation of a multistep proton transfer reaction involving protein residues, the proton relay shuttle between A and I forms of green fluorescent protein (GFP) is simulated in atomic detail by using a special molecular dynamics simulation technique. Electronic excitation of neutral chromophore in wild-typ...
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.052520799
更新日期:2002-03-05 00:00:00
abstract::The primary obstacle to producing renewable fuels from lignocellulosic biomass is a plant's recalcitrance to releasing sugars bound in the cell wall. From a sample set of wood cores representing 1,100 individual undomesticated Populus trichocarpa trees, 47 extreme phenotypes were selected across measured lignin conten...
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.1009252108
更新日期:2011-04-12 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::Tail-anchored (TA) membrane proteins are involved in a variety of important cellular functions, including membrane fusion, protein translocation, and apoptosis. The ATPase Get3 (Asna1, TRC40) was identified recently as the endoplasmic reticulum targeting factor of TA proteins. Get3 consists of an ATPase and alpha-heli...
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.0910223106
更新日期:2009-12-15 00:00:00
abstract::The Ca(2+) channel alpha(1A)-subunit is a voltage-gated, pore-forming membrane protein positioned at the intersection of two important lines of research: one exploring the diversity of Ca(2+) channels and their physiological roles, and the other pursuing mechanisms of ataxia, dystonia, epilepsy, and migraine. alpha(1A...
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.96.26.15245
更新日期:1999-12-21 00:00:00
abstract::The colligative properties of ATP and catecholamines demonstrated in vitro are thought to be responsible for the extraordinary accumulation of solutes inside chromaffin cell secretory vesicles, although this has yet to be demonstrated in living cells. Because functional cells cannot be deprived of ATP, we have knocked...
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.1600690113
更新日期:2016-07-12 00:00:00
abstract::Human T-cell leukemia virus type I (HTLV-I) is a causative agent of adult T-cell leukemia (ATL). To elucidate the role of HTLV-I in leukemogenesis, we examined the biological activity of a defective HTLV-I provirus with the env-pX 3' long terminal repeat region cloned from leukemic cells of an ATL patient. Transfectio...
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.87.3.1071
更新日期:1990-02-01 00:00:00
abstract::Lymphocyte homeostasis is the result of a critical balance between cell proliferation and death. Disruption of this subtle equilibrium can lead to the onset of leukemia, an increase in the number of lymphocytes being potentially due to both of these parameters. The relative importance of cell proliferation vs. apoptos...
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.142100999
更新日期:2002-07-23 00:00:00
abstract::Current evidence suggests that the length of poly(A) tails of bacterial mRNAs result from a competition between poly(A) polymerase and exoribonucleases that attack the 3' ends of RNAs. Here, we show that host factor Hfq is also involved in poly(A) tail metabolism. Inactivation of the hfq gene reduces the length of pol...
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.040549897
更新日期:2000-02-15 00:00:00
abstract::During endoplasmic reticulum-associated degradation, the multifunctional AAA ATPase p97 is part of a protein degradation complex. p97 associates via its N-terminal domain with various cofactors to recruit ubiquitinated substrates. It also interacts with alternative substrate-processing cofactors, such as Ufd2, Ufd3, 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.0702966104
更新日期:2007-05-22 00:00:00
abstract::In isogamous species of Chlamydomonas, such as Chlamydomonas reinhardtii and Chlamydomonas eugametos, the sexual process involves the use of flagella agglutinins by which the gametes of compatible strains adhere through chance encounter and ultimately pair and fuse to form zygotes. In a newly described heterogamous sp...
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.92.2.641
更新日期:1995-01-17 00:00:00