Abstract:
:Transposable elements make up half of the mammalian genome. One of the most abundant is the short interspersed nuclear element (SINE). Among their million copies, B2 accounts for ∼350,000 in the mouse genome and has garnered special interest because of emerging roles in epigenetic regulation. Our recent work demonstrated that B2 RNA binds stress genes to retard transcription elongation. Although epigenetically silenced, B2s become massively up-regulated during thermal and other types of stress. Specifically, an interaction between B2 RNA and the Polycomb protein, EZH2, results in cleavage of B2 RNA, release of B2 RNA from chromatin, and activation of thermal stress genes. Although an established RNA-binding protein and histone methyltransferase, EZH2 is not known to be a nuclease. Here, we provide evidence for the surprising conclusion that B2 is a self-cleaving ribozyme. Ribozyme activity depends on Mg+2 and monovalent cations but is resistant to protease treatment. However, contact with EZH2 accelerates cleavage rate by >100-fold, suggesting that EZH2 promotes a cleavage-competent RNA conformation. B2 modification-interference analysis demonstrates that phosphorothioate changes at A and C nucleotides can substitute for EZH2. B2 nucleotides 45 to 55 and 100 to 101 are essential for activity. Finally, another family of SINEs, the human ALU element, also produces a self-cleaving RNA and is cleaved during T-cell activation as well as thermal and endoplasmic reticulum (ER) stress. Thus, B2/ALU SINEs may be classified as "epigenetic ribozymes" that function as transcriptional switches during stress. Given their high copy numbers, B2 and ALU may represent the predominant ribozyme activity in mammalian cells.
journal_name
Proc Natl Acad Sci U S Aauthors
Hernandez AJ,Zovoilis A,Cifuentes-Rojas C,Han L,Bujisic B,Lee JTdoi
10.1073/pnas.1917190117subject
Has Abstractpub_date
2020-01-07 00:00:00pages
415-425issue
1eissn
0027-8424issn
1091-6490pii
1917190117journal_volume
117pub_type
杂志文章abstract::To elucidate the roles of IgE antibody in host responses to helminth infection, selective IgE-deficient SJA/9 mice were infected with the nematode parasites Nippostrongylus brasiliensis, which elicits remarkable potentiated IgE production, and Trichinella spiralis, which induces strong anti-Trichinella IgE antibody pr...
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.85.12.4460
更新日期:1988-06-01 00:00:00
abstract::A coenzyme B12-dependent ribonucleotide reductase was purified from the archaebacterium Thermoplasma acidophila and partially sequenced. Using probes derived from the sequence, the corresponding gene was cloned, completely sequenced, and expressed in Escherichia coli. The deduced amino acid sequence shows that 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.94.1.53
更新日期:1997-01-07 00:00:00
abstract::Understanding modulation of memory, as well as the mechanisms underlying memory formation, has become a key issue in neuroscience research. Previously, we found that the formation of long-term, but not short-term, memory for a nonassociative form of learning, sensitization, was modulated by the circadian clock in 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.0503847102
更新日期:2005-08-30 00:00:00
abstract::We have used oligonucleotide-directed mutagenesis to make a specific change in the beta-lactamase (EC 3.5.2.6) (ampicillin resistance) gene of the plasmid pBR322. Evidence suggests that the active site for this enzyme may include a serine-threonine dyad (residues 70 and 71). By priming in vitro DNA synthesis with a ch...
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.79.21.6409
更新日期:1982-11-01 00:00:00
abstract::Reward-guided decision-making depends on a network of brain regions. Among these are the orbitofrontal and the anterior cingulate cortex. However, it is difficult to ascertain if these areas constitute anatomical and functional unities, and how these areas correspond between monkeys and humans. To address these questi...
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.1410767112
更新日期:2015-05-19 00:00:00
abstract::The Mars Organic Analyzer (MOA), a microfabricated capillary electrophoresis (CE) instrument for sensitive amino acid biomarker analysis, has been developed and evaluated. The microdevice consists of a four-wafer sandwich combining glass CE separation channels, microfabricated pneumatic membrane valves and pumps, 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.0406798102
更新日期:2005-01-25 00:00:00
abstract::Noncompetitive inhibitors of the nicotinic acetylcholine (ACh) receptors suppress cation flux directly by binding in and blocking the open channel or indirectly by stabilizing closed states of the receptor. The lidocaine derivative QX-314 and the acridine derivative quinacrine act directly as open channel blockers, bu...
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.0730718100
更新日期:2003-04-01 00:00:00
abstract::We study the physical origins of phase contrast in dynamic atomic force microscopy (dAFM) in liquids where low-stiffness microcantilever probes are often used for nanoscale imaging of soft biological samples with gentle forces. Under these conditions, we show that the phase contrast derives primarily from a unique ene...
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.0902240106
更新日期:2009-08-18 00:00:00
abstract::The detrimental effects of elevated intensities of mid-UV radiation (UVB), a result of stratospheric ozone depletion during the austral spring, on the primary producers of the Antarctic marine ecosystem have been well documented. Here we report that natural populations of Antarctic zooplankton also sustain significant...
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.94.4.1258
更新日期:1997-02-18 00:00:00
abstract::Gene delivery to skeletal muscle is a promising strategy for the treatment of muscle disorders and for the systemic secretion of therapeutic proteins. However, present DNA delivery technologies have to be improved with regard to both the level of expression and interindividual variability. We report very efficient pla...
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.96.8.4262
更新日期:1999-04-13 00:00:00
abstract::The elongated three-helix bundle domains spectrin R16 and R17 fold some two to three orders of magnitude more slowly than their homologue R15. We have shown that this slow folding is due, at least in part, to roughness in the free-energy landscape of R16 and R17. We have proposed that this roughness is due to a frustr...
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.1201793109
更新日期:2012-10-30 00:00:00
abstract::The 82-residue amino-terminal sequences of simian virus 40 large tumor antigen (TAg) and small tumor antigen (tAg) are identical. Genetic analysis of TAg lacking amino acids 1-82 revealed that it was transformation-defective, as revealed by the agar growth assay, except when introduced in the presence of tAg. Since 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.87.19.7448
更新日期:1990-10-01 00:00:00
abstract::Phylogenetic differences in acetylcholine receptors from skeletal neuromuscular synapses of various species of snakes and lizards have been investigated, using the snake venom alpha-neurotoxins alpha-atratoxin (cobrotoxin) and alpha-bungarotoxin. The acetylcholine receptors of the phylogenetically primitive lizards, 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.72.8.3245
更新日期:1975-08-01 00:00:00
abstract::The conjugal transmission of plasmid ColE1 and its derivatives can lead to recA-independent recombination. The recombination is not observed during vegetative growth and takes place specifically between the sequences that are thought to represent the transfer origin of ColE1. This provides genetic evidence for breakag...
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.77.11.6724
更新日期:1980-11-01 00:00:00
abstract::The exquisite NMR spectral sensitivity and negligible reactivity of hyperpolarized xenon-129 (HP(129)Xe) make it attractive for a number of magnetic resonance applications; moreover, HP(129)Xe embodies an alternative to rare and nonrenewable (3)He. However, the ability to reliably and inexpensively produce large quant...
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.1306586110
更新日期:2013-08-27 00:00:00
abstract::Werner syndrome and Bloom syndrome result from defects in the RecQ helicases Werner (WRN) and Bloom (BLM), respectively, and display premature aging phenotypes. Similarly, XFE progeroid syndrome results from defects in the ERCC1-XPF DNA repair endonuclease. To gain insight into the origin of cellular senescence and hu...
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.1006338107
更新日期:2010-09-07 00:00:00
abstract::We have compared chicken erythrocyte linker histones H1 and H5 binding to a synthetic four-way DNA junction. Each histone binds to form a single complex, with an affinity which permits competition against a large excess of linear duplex DNA. The affinity of H5 is higher than that of H1. The globular domain from either...
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.91.9.3525
更新日期:1994-04-26 00:00:00
abstract::Viruses are the most common biological entities in the oceans by an order of magnitude. However, very little is known about their diversity. Here we report a genomic analysis of two uncultured marine viral communities. Over 65% of the sequences were not significantly similar to previously reported sequences, suggestin...
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.202488399
更新日期:2002-10-29 00:00:00
abstract::The transition to pulmonary respiration after birth requires rapid alterations in the structure of the mammalian cardiovascular system. One dramatic change that occurs is the closure of the ductus arteriosus (DA), an arterial connection in the fetus that directs blood flow away from the pulmonary circulation. Two memb...
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.1508386112
更新日期:2015-06-23 00:00:00
abstract::Extracellular cAMP plays a crucial role in regulating the developmental program of Dictyostelium discoideum, functioning as a chemotactic agent, as well as a signal that regulates expression of developmentally expressed genes. These activities appear to be mediated by a cell-surface receptor for cAMP. We have studied ...
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.84.4.1030
更新日期:1987-02-01 00:00:00
abstract::The heterogeneous RNA of the HeLa cell nucleus contains short internal poly(A) sequences which, in contrast to the longer poly(A) sequences at the 3' ends, are not found in messenger RNA of the cytoplasm. A distinct origin for each of these homologous sequences is evident when the effects of actinomycin D and 3'-deoxy...
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.71.1.200
更新日期:1974-01-01 00:00:00
abstract::We have previously shown that geographic differences in cancer mortalities in Europe are related to (in order of importance): geographic distances (reflecting environmental differences), ethnohistoric distances (encompassing cultural and genetic attributes), and genetic distances of the populations in the areas studie...
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.97.11.6067
更新日期:2000-05-23 00:00:00
abstract::The p53 tumor-suppressor protein is a critical mediator of cellular growth arrest and the induction of apoptosis. To identify proteins involved in the modulation of p53 transcriptional activity, a gain-of-function cellular screen was carried out with an arrayed matrix of approximately 20,000 cDNAs. Nine genes previous...
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.0308562100
更新日期:2004-03-09 00:00:00
abstract::We have previously shown that the isometric tension of a fully calcium-activated skinned rabbit psoas muscle fiber is reversibly depressed by increased hydrostatic pressure. We report here the characterization of tension transients induced by a rapid (less than 1-ms) release of increased pressure at 12 degrees C. 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.88.16.7323
更新日期:1991-08-15 00:00:00
abstract::Magnetic interactions between dissolved oxygen and nitroxide radical spin probes lead to broadening of the ESR lines. We have used a closed-chamber method based on this property to determine the maximum rate of O2 uptake per cell (Vmax per cell) in cultured mammalian cells. A suitable spin probe and a cell suspension ...
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.79.4.1166
更新日期:1982-02-01 00:00:00
abstract::The x-ray sensitive hamster cell line xrs-6 is deficient in DNA double-strand break (DSB) repair and exhibits impaired V(D)J recombination. The molecular defect in this line is in the 80-kDa subunit of the Ku autoantigen, a protein that binds to DNA ends and recruits the DNA-dependent protein kinase to DNA. Using an I...
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.93.17.8929
更新日期:1996-08-20 00:00:00
abstract::Fall migratory monarch butterflies, tested for their directional responses to magnetic cues under three conditions, amagnetic, normal, and reversed magnetic fields, showed three distinct patterns. In the absence of a magnetic field, monarchs lacked directionality as a group. In the normal magnetic field, monarchs orie...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,收录出版
doi:10.1073/pnas.96.24.13845
更新日期:1999-11-23 00:00:00
abstract::Rod-like colloids distort fluid interfaces and interact by capillarity. We explore this interaction at the free surface of aligned nematic liquid crystal films. Naive comparison of capillary and elastic energies suggests that particle assembly would be determined solely by surface tension. Here, we demonstrate that, 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.1504817112
更新日期:2015-05-19 00:00:00
abstract::The structure of the catalytically inactive mutant (C215S) of the human protein-tyrosine phosphatase 1B (PTP1B) has been solved to high resolution in two complexes. In the first, crystals were grown in the presence of bis-(para-phosphophenyl) methane (BPPM), a synthetic high-affinity low-molecular weight nonpeptidic 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.94.25.13420
更新日期:1997-12-09 00:00:00
abstract::The large class of adhesion G protein-coupled receptors (aGPCRs) bind extracellular matrix or neighboring cell-surface ligands to regulate organ and tissue development through an unknown activation mechanism. We examined aGPCR activation using two prototypical aGPCRs, GPR56 and GPR110. Active dissociation of the nonco...
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.1421785112
更新日期:2015-05-12 00:00:00