DNAase I sensitivity and methylation of active versus inactive rRNA genes in xenopus species hybrids.


:We studied the chromatin structure and methylation of ribosomal RNA genes (rDNA) in hybrids between Xenopus laevis and Xenopus borealis. S1-nuclease protection experiments showed that 97%-98% of the rRNA precursor in hybrid tadpoles was of the X. laevis type. Preferential expression of the laevis rDNA was correlated with its hypersensitivity to DNAase I compared to borealis rDNA. Borealis and laevis rDNAs gave equivalent methylation patterns, however. The results show that hypomethylated sites in the nontranscribed spacer are not sufficient to ensure DNAase I hypersensitivity or transcription of the borealis rDNA. Also, heavy methylation of the transcribed region of laevis rDNA is compatible with its hypersensitivity to DNAase I. The absence of coupling between hypomethylation and DNAase I sensitivity argues against the view that the methylation pattern directly triggers the active chromatin structure, though it does not exclude a less intimate relationship between transcription and DNA hypomethylation. Examination of borealis sperm rDNA showed that hypomethylated sites were present at the same spacer locations as in somatic cells. This contrasts with X. laevis, where hypomethylated sites are detectable in the spacer of somatic rDNA, but not in sperm. Thus the loss of spacer methylation that is seen in early development of X. laevis does not occur in X. borealis.






Macleod D,Bird A




Has Abstract


1982-05-01 00:00:00
















  • Cytohesins are cytoplasmic ErbB receptor activators.

    abstract::Signaling by ErbB receptors requires the activation of their cytoplasmic kinase domains, which is initiated by ligand binding to the receptor ectodomains. Cytoplasmic factors contributing to the activation are unknown. Here we identify members of the cytohesin protein family as such factors. Cytohesin inhibition decre...


    pub_type: 杂志文章,收录出版


    authors: Bill A,Schmitz A,Albertoni B,Song JN,Heukamp LC,Walrafen D,Thorwirth F,Verveer PJ,Zimmer S,Meffert L,Schreiber A,Chatterjee S,Thomas RK,Ullrich RT,Lang T,Famulok M

    更新日期:2010-10-15 00:00:00

  • Neither methylating nor demethylating enzymes are required for bacterial chemotaxis.

    abstract::Clarification of the information processing system in bacterial sensing has been obtained by studying mutants that lack the capacity to modify receptors covalently. The remaining part of the system is able to receive signals from the receptor, to respond with partial adaptation, and to exhibit a chemotactic response. ...


    pub_type: 杂志文章


    authors: Stock J,Kersulis G,Koshland DE Jr

    更新日期:1985-09-01 00:00:00

  • Architecture of a coat for the nuclear pore membrane.

    abstract::The symmetric core of the nuclear pore complex can be considered schematically as a series of concentric cylinders. A peripheral cylinder coating the pore membrane contains the previously characterized, elongated heptamer that harbors Sec13-Nup145C in its middle section. Strikingly, Sec13-Nup145C crystallizes as a het...


    pub_type: 杂志文章


    authors: Hsia KC,Stavropoulos P,Blobel G,Hoelz A

    更新日期:2007-12-28 00:00:00

  • Closing in on mechanisms of tissue morphogenesis.

    abstract::It remains largely unknown how large-scale tissue movements during development emerge from the interplay of different tensile forces associated with actomyosin networks. Solon et al. (2009) now report that a ratchet-like mechanism drives the movement of epithelial sheets during dorsal closure in embryos of the fruit f...


    pub_type: 评论,杂志文章


    authors: Rauzi M,Lecuit T

    更新日期:2009-06-26 00:00:00

  • Targeted overactivity of beta cell K(ATP) channels induces profound neonatal diabetes.

    abstract::A paradigm for control of insulin secretion is that glucose metabolism elevates cytoplasmic [ATP]/[ADP] in beta cells, closing K(ATP) channels and causing depolarization, Ca2+ entry, and insulin release. Decreased responsiveness of K(ATP) channels to elevated [ATP]/[ADP] should therefore lead to decreased insulin secr...


    pub_type: 杂志文章


    authors: Koster JC,Marshall BA,Ensor N,Corbett JA,Nichols CG

    更新日期:2000-03-17 00:00:00

  • Quiescence Modulates Stem Cell Maintenance and Regenerative Capacity in the Aging Brain.

    abstract::The function of somatic stem cells declines with age. Understanding the molecular underpinnings of this decline is key to counteract age-related disease. Here, we report a dramatic drop in the neural stem cells (NSCs) number in the aging murine brain. We find that this smaller stem cell reservoir is protected from ful...


    pub_type: 杂志文章


    authors: Kalamakis G,Brüne D,Ravichandran S,Bolz J,Fan W,Ziebell F,Stiehl T,Catalá-Martinez F,Kupke J,Zhao S,Llorens-Bobadilla E,Bauer K,Limpert S,Berger B,Christen U,Schmezer P,Mallm JP,Berninger B,Anders S,Del Sol A,Marc

    更新日期:2019-03-07 00:00:00

  • Myogenesis in primary cell cultures from Drosophila melanogaster: protein synthesis and actin heterogeneity during development.

    abstract::Muscle cell cultures from Drosophila melanogaster were obtained by plating dissociated gastrula stage embryo cells on protamine-treated culture dishes. They myogenic cells in these cultures fuse to form multinucleated pulsating cells by 15 hr after plating. An analysis of protein synthesis during myogenesis in these c...


    pub_type: 杂志文章


    authors: Storti RV,Horovitch SJ,Scott MP,Rich A,Pardue ML

    更新日期:1978-04-01 00:00:00

  • Dancing with the host; flow-dependent bacterial adhesion.

    abstract::Most bacteria that colonize eukaryotes must bind directly to host cells to establish a replicative niche. In enteric bacteria, adhesion to host cells is often promoted by a lectin found on surface-localized pili. Some pili promote efficient adhesion only when they are subjected to shear stress, as found during the flo...


    pub_type: 杂志文章,评审


    authors: Isberg RR,Barnes P

    更新日期:2002-07-12 00:00:00

  • A tethering complex recruits SNAREs and grabs vesicles.

    abstract::Protein tethers can bridge gaps between membranes. Ren et al. (2009) now provide evidence that the yeast Dsl1 complex tethers vesicles to the endoplasmic reticulum (ER) by binding ER SNARE proteins at its base and capturing vesicles using a loop region that extends 20 nm from the ER membrane. ...


    pub_type: 评论,杂志文章


    authors: Schmitt HD,Jahn R

    更新日期:2009-12-11 00:00:00

  • Kinetochore localization of murine Bub1 is required for normal mitotic timing and checkpoint response to spindle damage.

    abstract::The mitotic checkpoint ensures proper chromosome segregation by delaying anaphase until chromosomes are aligned on the spindle. Following prolonged spindle damage, however, cells eventually exit mitosis and undergo apoptosis. We show here that a murine homolog of the yeast mitotic checkpoint gene BUB1 localizes to the...


    pub_type: 杂志文章


    authors: Taylor SS,McKeon F

    更新日期:1997-05-30 00:00:00

  • Synonymous mutations frequently act as driver mutations in human cancers.

    abstract::Synonymous mutations change the sequence of a gene without directly altering the sequence of the encoded protein. Here, we present evidence that these "silent" mutations frequently contribute to human cancer. Selection on synonymous mutations in oncogenes is cancer-type specific, and although the functional consequenc...


    pub_type: 杂志文章


    authors: Supek F,Miñana B,Valcárcel J,Gabaldón T,Lehner B

    更新日期:2014-03-13 00:00:00

  • Mechanisms of conformational change for a replicative hexameric helicase of SV40 large tumor antigen.

    abstract::The large tumor antigen (LTag) of simian virus 40, an AAA(+) protein, is a hexameric helicase essential for viral DNA replication in eukaryotic cells. LTag functions as an efficient molecular machine powered by ATP binding and hydrolysis for origin DNA melting and replication fork unwinding. To understand how ATP bind...


    pub_type: 杂志文章


    authors: Gai D,Zhao R,Li D,Finkielstein CV,Chen XS

    更新日期:2004-10-01 00:00:00

  • Coordinated leading and lagging strand synthesis during SV40 DNA replication in vitro requires PCNA.

    abstract::Proliferating cell nuclear antigen (PCNA) is a cell cycle and growth regulated protein required for replication of SV40 DNA in vitro. Its function was investigated by comparison of the replication products synthesized in its presence or absence. In the completely reconstituted replication system that contains PCNA, DN...


    pub_type: 杂志文章


    authors: Prelich G,Stillman B

    更新日期:1988-04-08 00:00:00

  • Phosphorylation of the R domain by cAMP-dependent protein kinase regulates the CFTR chloride channel.

    abstract::CFTR, the protein associated with cystic fibrosis, is phosphorylated on serine residues in response to cAMP agonists. Serines 660, 737, 795, and 813 were identified as in vivo targets for phosphorylation by protein kinase A. The SPQ fluorescence assay revealed that mutagenesis of any one of these sites did not affect ...


    pub_type: 杂志文章


    authors: Cheng SH,Rich DP,Marshall J,Gregory RJ,Welsh MJ,Smith AE

    更新日期:1991-09-06 00:00:00

  • Specialized piRNA pathways act in germline and somatic tissues of the Drosophila ovary.

    abstract::In Drosophila gonads, Piwi proteins and associated piRNAs collaborate with additional factors to form a small RNA-based immune system that silences mobile elements. Here, we analyzed nine Drosophila piRNA pathway mutants for their impacts on both small RNA populations and the subcellular localization patterns of Piwi ...


    pub_type: 杂志文章


    authors: Malone CD,Brennecke J,Dus M,Stark A,McCombie WR,Sachidanandam R,Hannon GJ

    更新日期:2009-05-01 00:00:00

  • Critical sequences within mitochondrial introns: pleiotropic mRNA maturase and cis-dominant signals of the box intron controlling reductase and oxidase.

    abstract::We have established the DNA sequence of nine yeast mutants that prevent the expression either of the split cytochrome b gene alone (five mutants) or of two split genes, the cytochrome b gene and the cytochrome oxidase subunit I gene (four mutants). All the mutations analyzed are localized in intron 14 of the cob-box g...


    pub_type: 杂志文章


    authors: De La Salle H,Jacq C,Slonimski PP

    更新日期:1982-04-01 00:00:00

  • Efficient direct reprogramming of mature amniotic cells into endothelial cells by ETS factors and TGFβ suppression.

    abstract::ETS transcription factors ETV2, FLI1, and ERG1 specify pluripotent stem cells into induced vascular endothelial cells (iVECs). However, iVECs are unstable and drift toward nonvascular cells. We show that human midgestation c-Kit(-) lineage-committed amniotic cells (ACs) can be reprogrammed into vascular endothelial ce...


    pub_type: 杂志文章


    authors: Ginsberg M,James D,Ding BS,Nolan D,Geng F,Butler JM,Schachterle W,Pulijaal VR,Mathew S,Chasen ST,Xiang J,Rosenwaks Z,Shido K,Elemento O,Rabbany SY,Rafii S

    更新日期:2012-10-26 00:00:00

  • Characterization of Op3, a lysis-defective mutant of bacteriophage f2.

    abstract::We have isolated a conditional lethal mutant of bacteriophage 12 which makes plaques only on E. coli strains carrying a UGA suppressor. It grows normally in nonsuppressing hosts but does not lyse such strains. The mutation complements with amber mutations in each of the three known phage cistrons. These observations l...


    pub_type: 杂志文章


    authors: Model P,Webster RE,Zinder ND

    更新日期:1979-10-01 00:00:00

  • Coding of sweet, bitter, and umami tastes: different receptor cells sharing similar signaling pathways.

    abstract::Mammals can taste a wide repertoire of chemosensory stimuli. Two unrelated families of receptors (T1Rs and T2Rs) mediate responses to sweet, amino acids, and bitter compounds. Here, we demonstrate that knockouts of TRPM5, a taste TRP ion channel, or PLCbeta2, a phospholipase C selectively expressed in taste tissue, ab...


    pub_type: 评论,杂志文章


    authors: Zhang Y,Hoon MA,Chandrashekar J,Mueller KL,Cook B,Wu D,Zuker CS,Ryba NJ

    更新日期:2003-02-07 00:00:00

  • The evolution of adaptive immune systems.

    abstract::A clonally diverse anticipatory repertoire in which each lymphocyte bears a unique antigen receptor is the central feature of the adaptive immune system that evolved in our vertebrate ancestors. The survival advantage gained through adding this type of adaptive immune system to a pre-existing innate immune system led ...


    pub_type: 杂志文章,评审


    authors: Cooper MD,Alder MN

    更新日期:2006-02-24 00:00:00

  • Otoferlin, defective in a human deafness form, is essential for exocytosis at the auditory ribbon synapse.

    abstract::The auditory inner hair cell (IHC) ribbon synapse operates with an exceptional temporal precision and maintains a high level of neurotransmitter release. However, the molecular mechanisms underlying IHC synaptic exocytosis are largely unknown. We studied otoferlin, a predicted C2-domain transmembrane protein, which is...


    pub_type: 杂志文章


    authors: Roux I,Safieddine S,Nouvian R,Grati M,Simmler MC,Bahloul A,Perfettini I,Le Gall M,Rostaing P,Hamard G,Triller A,Avan P,Moser T,Petit C

    更新日期:2006-10-20 00:00:00

  • Proteomic Analysis of Unbounded Cellular Compartments: Synaptic Clefts.

    abstract::Cellular compartments that cannot be biochemically isolated are challenging to characterize. Here we demonstrate the proteomic characterization of the synaptic clefts that exist at both excitatory and inhibitory synapses. Normal brain function relies on the careful balance of these opposing neural connections, and und...


    pub_type: 杂志文章


    authors: Loh KH,Stawski PS,Draycott AS,Udeshi ND,Lehrman EK,Wilton DK,Svinkina T,Deerinck TJ,Ellisman MH,Stevens B,Carr SA,Ting AY

    更新日期:2016-08-25 00:00:00

  • Colorectal Cancer Cells Enter a Diapause-like DTP State to Survive Chemotherapy.

    abstract::Cancer cells enter a reversible drug-tolerant persister (DTP) state to evade death from chemotherapy and targeted agents. It is increasingly appreciated that DTPs are important drivers of therapy failure and tumor relapse. We combined cellular barcoding and mathematical modeling in patient-derived colorectal cancer mo...


    pub_type: 杂志文章


    authors: Rehman SK,Haynes J,Collignon E,Brown KR,Wang Y,Nixon AML,Bruce JP,Wintersinger JA,Singh Mer A,Lo EBL,Leung C,Lima-Fernandes E,Pedley NM,Soares F,McGibbon S,He HH,Pollet A,Pugh TJ,Haibe-Kains B,Morris Q,Ramalho-San

    更新日期:2021-01-07 00:00:00

  • Domain reorientation and rotation of an intracellular assembly regulate conduction in Kir potassium channels.

    abstract::Potassium channels embedded in cell membranes employ gates to regulate K+ current. While a specific constriction in the permeation pathway has historically been implicated in gating, recent reports suggest that the signature ion selectivity filter located in the outer membrane leaflet may be equally important. Inwardl...


    pub_type: 杂志文章


    authors: Clarke OB,Caputo AT,Hill AP,Vandenberg JI,Smith BJ,Gulbis JM

    更新日期:2010-06-11 00:00:00

  • NMR structure of the bacteriophage lambda N peptide/boxB RNA complex: recognition of a GNRA fold by an arginine-rich motif.

    abstract::The structure of the complex formed by the arginine-rich motif of the transcriptional antitermination protein N of phage lambda and boxB RNA was determined by heteronuclear magnetic resonance spectroscopy. A bent alpha helix in N recognizes primarily the shape and negatively charged surface of the boxB hairpin through...


    pub_type: 杂志文章


    authors: Legault P,Li J,Mogridge J,Kay LE,Greenblatt J

    更新日期:1998-04-17 00:00:00

  • Metformin retards aging in C. elegans by altering microbial folate and methionine metabolism.

    abstract::The biguanide drug metformin is widely prescribed to treat type 2 diabetes and metabolic syndrome, but its mode of action remains uncertain. Metformin also increases lifespan in Caenorhabditis elegans cocultured with Escherichia coli. This bacterium exerts complex nutritional and pathogenic effects on its nematode pre...


    pub_type: 杂志文章


    authors: Cabreiro F,Au C,Leung KY,Vergara-Irigaray N,Cochemé HM,Noori T,Weinkove D,Schuster E,Greene ND,Gems D

    更新日期:2013-03-28 00:00:00

  • How TriC folds tricky proteins.

    abstract::How chaperonins orchestrate the successful folding of even the most elaborate of proteins is a question of central importance. In two recent studies in Cell by Joachimiak et al. and Freund et al., a new class of TRiC substrate is identified, and how the chaperonin exploits its different subunits to extend its substrat...


    pub_type: 评论,杂志文章


    authors: Zhuravleva A,Radford SE

    更新日期:2014-12-04 00:00:00

  • An Engineered CRISPR-Cas9 Mouse Line for Simultaneous Readout of Lineage Histories and Gene Expression Profiles in Single Cells.

    abstract::Tracing the lineage history of cells is key to answering diverse and fundamental questions in biology. Coupling of cell ancestry information with other molecular readouts represents an important goal in the field. Here, we describe the CRISPR array repair lineage tracing (CARLIN) mouse line and corresponding analysis ...


    pub_type: 杂志文章


    authors: Bowling S,Sritharan D,Osorio FG,Nguyen M,Cheung P,Rodriguez-Fraticelli A,Patel S,Yuan WC,Fujiwara Y,Li BE,Orkin SH,Hormoz S,Camargo FD

    更新日期:2020-06-11 00:00:00

  • Fusion of the Escherichia coli tRNALeu1 promoter to the galK gene: analysis of sequences necessary for growth-rate-dependent regulation.

    abstract::We have fused DNA fragments derived from an Escherichia coli tRNALeu1 operon to the galK gene of E. coli to identify sequences necessary for the in vivo initiation of transcription and growth-rate-dependent regulation. Promoter sequences consisting of residues from -50 to +56 or -50 to +5 with respect to the in vivo s...


    pub_type: 杂志文章


    authors: Duester G,Elford RM,Holmes WM

    更新日期:1982-10-01 00:00:00

  • The diabetes susceptibility gene Clec16a regulates mitophagy.

    abstract::Clec16a has been identified as a disease susceptibility gene for type 1 diabetes, multiple sclerosis, and adrenal dysfunction, but its function is unknown. Here we report that Clec16a is a membrane-associated endosomal protein that interacts with E3 ubiquitin ligase Nrdp1. Loss of Clec16a leads to an increase in the N...


    pub_type: 杂志文章


    authors: Soleimanpour SA,Gupta A,Bakay M,Ferrari AM,Groff DN,Fadista J,Spruce LA,Kushner JA,Groop L,Seeholzer SH,Kaufman BA,Hakonarson H,Stoffers DA

    更新日期:2014-06-19 00:00:00