journal
https://read.qxmd.com/read/24482483/timing-mechanism-dependent-on-cell-division-is-invoked-by-polycomb-eviction-in-plant-stem-cells
#1
JOURNAL ARTICLE
Bo Sun, Liang-Sheng Looi, Siyi Guo, Zemiao He, Eng-Seng Gan, Jiangbo Huang, Yifeng Xu, Wan-Yi Wee, Toshiro Ito
Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay. AG binding sites colocalize with a Polycomb response element in the KNU upstream region...
January 31, 2014: Science
https://read.qxmd.com/read/24482466/the-changing-role-of-medieval-women
#2
LETTER
Richard E Blanton
No abstract text is available yet for this article.
January 31, 2014: Science
https://read.qxmd.com/read/24482464/fueling-innovation
#3
LETTER
Rodney W Nichols
No abstract text is available yet for this article.
January 31, 2014: Science
https://read.qxmd.com/read/23990550/materials-science-a-clear-advance-in-soft-actuators
#4
COMMENT
John A Rogers
No abstract text is available yet for this article.
August 30, 2013: Science
https://read.qxmd.com/read/23929978/a-semi-floating-gate-transistor-for-low-voltage-ultrafast-memory-and-sensing-operation
#5
JOURNAL ARTICLE
Peng-Fei Wang, Xi Lin, Lei Liu, Qing-Qing Sun, Peng Zhou, Xiao-Yong Liu, Wei Liu, Yi Gong, David Wei Zhang
As the semiconductor devices of integrated circuits approach the physical limitations of scaling, alternative transistor and memory designs are needed to achieve improvements in speed, density, and power consumption. We report on a transistor that uses an embedded tunneling field-effect transistor for charging and discharging the semi-floating gate. This transistor operates at low voltages (≤2.0 volts), with a large threshold voltage window of 3.1 volts, and can achieve ultra-high-speed writing operations (on time scales of ~1 nanosecond)...
August 9, 2013: Science
https://read.qxmd.com/read/23896459/the-evolution-of-social-monogamy-in-mammals
#6
JOURNAL ARTICLE
D Lukas, T H Clutton-Brock
The evolution of social monogamy has intrigued biologists for over a century. Here, we show that the ancestral condition for all mammalian groups is of solitary individuals and that social monogamy is derived almost exclusively from this social system. The evolution of social monogamy does not appear to have been associated with a high risk of male infanticide, and paternal care is a consequence rather than a cause of social monogamy. Social monogamy has evolved in nonhuman mammals where breeding females are intolerant of each other and female density is low, suggesting that it represents a mating strategy that has developed where males are unable to defend access to multiple females...
August 2, 2013: Science
https://read.qxmd.com/read/23888043/mtorc1-phosphorylation-sites-encode-their-sensitivity-to-starvation-and-rapamycin
#7
JOURNAL ARTICLE
Seong A Kang, Michael E Pacold, Christopher L Cervantes, Daniel Lim, Hua Jane Lou, Kathleen Ottina, Nathanael S Gray, Benjamin E Turk, Michael B Yaffe, David M Sabatini
The mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) protein kinase promotes growth and is the target of rapamycin, a clinically useful drug that also prolongs life span in model organisms. A persistent mystery is why the phosphorylation of many bona fide mTORC1 substrates is resistant to rapamycin. We find that the in vitro kinase activity of mTORC1 toward peptides encompassing established phosphorylation sites varies widely and correlates strongly with the resistance of the sites to rapamycin, as well as to nutrient and growth factor starvation within cells...
July 26, 2013: Science
https://read.qxmd.com/read/23828942/somatic-mutation-genomic-variation-and-neurological-disease
#8
JOURNAL ARTICLE
Annapurna Poduri, Gilad D Evrony, Xuyu Cai, Christopher A Walsh
Genetic mutations causing human disease are conventionally thought to be inherited through the germ line from one's parents and present in all somatic (body) cells, except for most cancer mutations, which arise somatically. Increasingly, somatic mutations are being identified in diseases other than cancer, including neurodevelopmental diseases. Somatic mutations can arise during the course of prenatal brain development and cause neurological disease-even when present at low levels of mosaicism, for example-resulting in brain malformations associated with epilepsy and intellectual disability...
July 5, 2013: Science
https://read.qxmd.com/read/23828889/real-time-dynamics-of-rna-polymerase-ii-clustering-in-live-human-cells
#9
JOURNAL ARTICLE
Ibrahim I Cisse, Ignacio Izeddin, Sebastien Z Causse, Lydia Boudarene, Adrien Senecal, Leila Muresan, Claire Dugast-Darzacq, Bassam Hajj, Maxime Dahan, Xavier Darzacq
Transcription is reported to be spatially compartmentalized in nuclear transcription factories with clusters of RNA polymerase II (Pol II). However, little is known about when these foci assemble or their relative stability. We developed a quantitative single-cell approach to characterize protein spatiotemporal organization, with single-molecule sensitivity in live eukaryotic cells. We observed that Pol II clusters form transiently, with an average lifetime of 5.1 (± 0.4) seconds, which refutes the notion that they are statically assembled substructures...
August 9, 2013: Science
https://read.qxmd.com/read/23828888/the-xist-lncrna-exploits-three-dimensional-genome-architecture-to-spread-across-the-x-chromosome
#10
JOURNAL ARTICLE
Jesse M Engreitz, Amy Pandya-Jones, Patrick McDonel, Alexander Shishkin, Klara Sirokman, Christine Surka, Sabah Kadri, Jeffrey Xing, Alon Goren, Eric S Lander, Kathrin Plath, Mitchell Guttman
Many large noncoding RNAs (lncRNAs) regulate chromatin, but the mechanisms by which they localize to genomic targets remain unexplored. We investigated the localization mechanisms of the Xist lncRNA during X-chromosome inactivation (XCI), a paradigm of lncRNA-mediated chromatin regulation. During the maintenance of XCI, Xist binds broadly across the X chromosome. During initiation of XCI, Xist initially transfers to distal regions across the X chromosome that are not defined by specific sequences. Instead, Xist identifies these regions by exploiting the three-dimensional conformation of the X chromosome...
August 16, 2013: Science
https://read.qxmd.com/read/23828887/ultrahigh-magnetoresistance-at-room-temperature-in-molecular-wires
#11
JOURNAL ARTICLE
R N Mahato, H Lülf, M H Siekman, S P Kersten, P A Bobbert, M P de Jong, L De Cola, W G van der Wiel
Systems featuring large magnetoresistance (MR) at room temperature and in small magnetic fields are attractive owing to their potential for applications in magnetic field sensing and data storage. Usually, the magnetic properties of materials are exploited to achieve large MR effects. Here, we report on an exceptionally large (>2000%), room-temperature, small-field (a few millitesla) MR effect in one-dimensional, nonmagnetic systems formed by molecular wires embedded in a zeolite host crystal. This ultrahigh MR effect is ascribed to spin blockade in one-dimensional electron transport...
July 19, 2013: Science
https://read.qxmd.com/read/23812704/chemistry-more-can-be-better-in-n2-activation
#12
COMMENT
Michael D Fryzuk
No abstract text is available yet for this article.
June 28, 2013: Science
https://read.qxmd.com/read/23812701/good-grades-for-dual-education
#13
LETTER
Xi Chen, Qiang Wang
No abstract text is available yet for this article.
June 28, 2013: Science
https://read.qxmd.com/read/23812700/reversing-excess-atmospheric-co2-response
#14
LETTER
Damon Matthews, Susan Solomon
No abstract text is available yet for this article.
June 28, 2013: Science
https://read.qxmd.com/read/23661644/gpr15-mediated-homing-controls-immune-homeostasis-in-the-large-intestine-mucosa
#15
JOURNAL ARTICLE
Sangwon V Kim, Wenkai V Xiang, Changsoo Kwak, Yi Yang, Xiyao W Lin, Mitsuhiko Ota, Umut Sarpel, Daniel B Rifkin, Ruliang Xu, Dan R Littman
Lymphocyte homing, which contributes to inflammation, has been studied extensively in the small intestine, but there is little known about homing to the large intestine, the site most commonly affected in inflammatory bowel disease. GPR15, an orphan heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor, controlled the specific homing of T cells, particularly FOXP3(+) regulatory T cells (Tregs), to the large intestine lamina propria (LILP). GPR15 expression was modulated by gut microbiota and transforming growth factor-β1, but not by retinoic acid...
June 21, 2013: Science
https://read.qxmd.com/read/23723234/an-adaptive-response-to-uncertainty-generates-positive-and-negative-contrast-effects
#16
JOURNAL ARTICLE
John M McNamara, Tim W Fawcett, Alasdair I Houston
Successive contrast effects, in which behavior is dependent on whether conditions are currently better or worse than they were before, are a striking illustration of the fact that animals evaluate the world in relative terms. Existing explanations for these effects are based on descriptive models of psychological and physiological processes, but little attention has been paid to the factors promoting their evolution. Using a simple and general optimality model, we show that contrast effects can result from an adaptive response to uncertainty in a changing, unpredictable world...
May 31, 2013: Science
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