GSTDTAP

浏览/检索结果: 共24条,第1-10条 帮助

限定条件    
已选(0)清除 条数/页:   排序方式:
The first dinosaur egg was soft 期刊论文
NATURE, 2020
作者:  Rodstrom, Karin E. J.;  Kiper, Aytug K.;  Zhang, Wei;  Rinne, Susanne;  Pike, Ashley C. W.;  Goldstein, Matthias;  Conrad, Linus J.;  Delbeck, Martina;  Hahn, Michael G.;  Meier, Heinrich;  Platzk, Magdalena;  Quigley, Andrew;  Speedman, David;  Shrestha, Leela;  Mukhopadhyay, Shubhashish M. M.
收藏  |  浏览/下载:47/0  |  提交时间:2020/07/03

Molecular analyses of newly discovered, embryo-bearing ornithischian and sauropod dinosaur eggs suggest that the ancestral dinosaur egg was soft-shelled, and that hard-shelled eggs evolved independently at least three times in the major dinosaur lineages.


Calcified eggshells protect developing embryos against environmental stress and contribute to reproductive success(1). As modern crocodilians and birds lay hard-shelled eggs, this eggshell type has been inferred for non-avian dinosaurs. Known dinosaur eggshells are characterized by an innermost membrane, an overlying protein matrix containing calcite, and an outermost waxy cuticle(2-7). The calcitic eggshell consists of one or more ultrastructural layers that differ markedly among the three major dinosaur clades, as do the configurations of respiratory pores. So far, only hadrosaurid, a few sauropodomorph and tetanuran eggshells have been discovered  the paucity of the fossil record and the lack of intermediate eggshell types challenge efforts to homologize eggshell structures across all dinosaurs(8-18). Here we present mineralogical, organochemical and ultrastructural evidence for an originally non-biomineralized, soft-shelled nature of exceptionally preserved ornithischianProtoceratopsand basal sauropodomorphMussauruseggs. Statistical evaluation of in situ Raman spectra obtained for a representative set of hard- and soft-shelled, fossil and extant diapsid eggshells clusters the originally organic but secondarily phosphatizedProtoceratopsand the organicMussauruseggshells with soft, non-biomineralized eggshells. Histology corroborates the organic composition of these soft-shelled dinosaur eggs, revealing a stratified arrangement resembling turtle soft eggshell. Through an ancestral-state reconstruction of composition and ultrastructure, we compare eggshells fromProtoceratopsandMussauruswith those from other diapsids, revealing that the first dinosaur egg was soft-shelled. The calcified, hard-shelled dinosaur egg evolved independently at least three times throughout the Mesozoic era, explaining the bias towards eggshells of derived dinosaurs in the fossil record.


  
Molecular architecture of the human 17S U2 snRNP 期刊论文
NATURE, 2020, 583 (7815) : 310-+
作者:  Muench, David E.;  Olsson, Andre;  Ferchen, Kyle;  Pham, Giang;  Serafin, Rachel A.;  Chutipongtanate, Somchai;  Dwivedi, Pankaj;  Song, Baobao;  Hay, Stuart;  Chetal, Kashish;  Trump-Durbin, Lisa R.;  Mookerjee-Basu, Jayati;  Zhang, Kejian;  Yu, Jennifer C.
收藏  |  浏览/下载:18/0  |  提交时间:2020/07/03

The U2 small nuclear ribonucleoprotein (snRNP) has an essential role in the selection of the precursor mRNA branch-site adenosine, the nucleophile for the first step of splicing'  . Stable addition of U2 during early spliceosome formation requiresthe DEAD-box ATPase PRP5(2-7). Yeast U2 small nuclear RNA (snRNA) nucleotides that form base pairs with the branch site are initially sequestered in a branchpoint-interacting stem-loop (BSL)(8), but whether the human U2 snRNA folds in a similar manner is unknown. The U2 SF3B1 protein, a common mutational target in haematopoietic cancers(9), contains a HEAT domain (SF3B1(HEAT)) with an open conformation in isolated SF3b(10), but a closed conformation in spliceosomes(11), which is required for stable interaction between U2 and the branch site. Here we report a 3D cryo-electron microscopy structure ofthe human 17S U2 snRNP at a core resolution of 4.1 angstrom and combine it with protein crosslinking data to determine the molecular architecture of this snRNP. Our structure reveals that SF3B1(HEAT) interacts with PRP5 and TAT-SF1, and maintains its open conformation in U2 snRNP, and that U2 snRNA forms a BSL that is sandwiched between PRP5, TAT-SF1 and SF3B1(HEAT). Thus, substantial remodelling of the BSL and displacement of BSL-interacting proteins must occur to allow formation of the U2-branch-site helix. Our studies provide a structural explanation of why TAT-SF1 must be displaced before the stable addition of U2 to the spliceosome, and identify RNP rearrangements facilitated by PRP5 that are required for stable interaction between U2 and the branch site.


  
Structure and mechanism of human diacylglycerol O-acyltransferase 1 期刊论文
NATURE, 2020, 581 (7808) : 329-+
作者:  Wu, Fan;  Zhao, Su;  Yu, Bin;  Chen, Yan-Mei;  Wang, Wen;  Song, Zhi-Gang;  Hu, Yi;  Tao, Zhao-Wu;  Tian, Jun-Hua;  Pei, Yuan-Yuan;  Yuan, Ming-Li;  Zhang, Yu-Ling;  Dai, Fa-Hui;  Liu, Yi;  Wang, Qi-Min;  Zheng, Jiao-Jiao;  Xu, Lin;  Holmes, Edward C.;  Zhang, Yong-Zhen
收藏  |  浏览/下载:24/0  |  提交时间:2020/07/03

The structure of human diacylglycerol O-acyltransferase 1, a membrane protein that synthesizes triacylglycerides, is solved with cryo-electron microscopy, providing insight into its function and mechanism of enzymatic activity.


Diacylglycerol O-acyltransferase 1 (DGAT1) synthesizes triacylglycerides and is required for dietary fat absorption and fat storage in humans(1). DGAT1 belongs to the membrane-bound O-acyltransferase (MBOAT) superfamily, members of which are found in all kingdoms of life and are involved in the acylation of lipids and proteins(2,3). How human DGAT1 and other mammalian members of the MBOAT family recognize their substrates and catalyse their reactions is unknown. The absence of three-dimensional structures also hampers rational targeting of DGAT1 for therapeutic purposes. Here we present the cryo-electron microscopy structure of human DGAT1 in complex with an oleoyl-CoA substrate. Each DGAT1 protomer has nine transmembrane helices, eight of which form a conserved structural fold that we name the MBOAT fold. The MBOAT fold in DGAT1 forms a hollow chamber in the membrane that encloses highly conserved catalytic residues. The chamber has separate entrances for each of the two substrates, fatty acyl-CoA and diacylglycerol. DGAT1 can exist as either a homodimer or a homotetramer and the two forms have similar enzymatic activity. The N terminus of DGAT1 interacts with the neighbouring protomer and these interactions are required for enzymatic activity.


  
The online competition between pro- and anti-vaccination views 期刊论文
NATURE, 2020, 582 (7811) : 230-+
作者:  Wu, Fan;  Zhao, Su;  Yu, Bin;  Chen, Yan-Mei;  Wang, Wen;  Song, Zhi-Gang;  Hu, Yi;  Tao, Zhao-Wu;  Tian, Jun-Hua;  Pei, Yuan-Yuan;  Yuan, Ming-Li;  Zhang, Yu-Ling;  Dai, Fa-Hui;  Liu, Yi;  Wang, Qi-Min;  Zheng, Jiao-Jiao;  Xu, Lin;  Holmes, Edward C.;  Zhang, Yong-Zhen
收藏  |  浏览/下载:10/0  |  提交时间:2020/07/03

Insights into the interactions between pro- and anti-vaccination clusters on Facebook can enable policies and approaches that attempt to interrupt the shift to anti-vaccination views and persuade undecided individuals to adopt a pro-vaccination stance.


Distrust in scientific expertise(1-14) is dangerous. Opposition to vaccination with a future vaccine against SARS-CoV-2, the causal agent of COVID-19, for example, could amplify outbreaks(2-4), as happened for measles in 2019(5,6). Homemade remedies(7,8) and falsehoods are being shared widely on the Internet, as well as dismissals of expert advice(9-11). There is a lack of understanding about how this distrust evolves at the system level(13,14). Here we provide a map of the contention surrounding vaccines that has emerged from the global pool of around three billion Facebook users. Its core reveals a multi-sided landscape of unprecedented intricacy that involves nearly 100 million individuals partitioned into highly dynamic, interconnected clusters across cities, countries, continents and languages. Although smaller in overall size, anti-vaccination clusters manage to become highly entangled with undecided clusters in the main online network, whereas pro-vaccination clusters are more peripheral. Our theoretical framework reproduces the recent explosive growth in anti-vaccination views, and predicts that these views will dominate in a decade. Insights provided by this framework can inform new policies and approaches to interrupt this shift to negative views. Our results challenge the conventional thinking about undecided individuals in issues of contention surrounding health, shed light on other issues of contention such as climate change(11), and highlight the key role of network cluster dynamics in multi-species ecologies(15).


  
A lower X-gate in TASK channels traps inhibitors within the vestibule 期刊论文
NATURE, 2020
作者:  Chen, Tao;  Nomura, Kinya;  Wang, Xiaolin;  Sohrabi, Reza;  Xu, Jin;  Yao, Lingya;  Paasch, Bradley C.;  Ma, Li;  Kremer, James;  Cheng, Yuti;  Zhang, Li;  Wang, Nian;  Wang, Ertao;  Xin, Xiu-Fang;  He, Sheng Yang
收藏  |  浏览/下载:32/0  |  提交时间:2020/07/03

TWIK-related acid-sensitive potassium (TASK) channels-members of the two pore domain potassium (K-2P) channel family-are found in neurons(1), cardiomyocytes(2-4) and vascular smooth muscle cells(5), where they are involved in the regulation of heart rate(6), pulmonary artery tone(5,7), sleep/wake cycles(8) and responses to volatile anaesthetics(8-11). K-2P channels regulate the resting membrane potential, providing background K+ currents controlled by numerous physiological stimuli(12-15). Unlike other K-2P channels, TASK channels are able to bind inhibitors with high affinity, exceptional selectivity and very slow compound washout rates. As such, these channels are attractive drug targets, and TASK-1 inhibitors are currently in clinical trials for obstructive sleep apnoea and atrial fibrillation(16). In general, potassium channels have an intramembrane vestibule with a selectivity filter situated above and a gate with four parallel helices located below  however, the K-2P channels studied so far all lack a lower gate. Here we present the X-ray crystal structure of TASK-1, and show that it contains a lower gate-which we designate as an '  X-gate'  -created by interaction of the two crossed C-terminal M4 transmembrane helices at the vestibule entrance. This structure is formed by six residues ((VLRFMT248)-V-243) that are essential for responses to volatile anaesthetics(10), neurotransmitters(13) and G-protein-coupled receptors(13). Mutations within the X-gate and the surrounding regions markedly affect both the channel-open probability and the activation of the channel by anaesthetics. Structures of TASK-1 bound to two high-affinity inhibitors show that both compounds bind below the selectivity filter and are trapped in the vestibule by the X-gate, which explains their exceptionally low washout rates. The presence of the X-gate in TASK channels explains many aspects of their physiological and pharmacological behaviour, which will be beneficial for the future development and optimization of TASK modulators for the treatment of heart, lung and sleep disorders.


The X-ray crystal structure of the potassium channel TASK-1 reveals the presence of an X-gate, which traps small-molecule inhibitors in the intramembrane vestibule and explains their low washout rates from the channel.


  
Nanoplasma-enabled picosecond switches for ultrafast electronics (vol 579, pg 534, 2020) 期刊论文
NATURE, 2020, 580 (7803) : E8-E8
作者:  Li, Jing;  Xu, Chuanliang;  Lee, Hyung Joo;  Ren, Shancheng;  Zi, Xiaoyuan;  Zhang, Zhiming;  Wang, Haifeng;  Yu, Yongwei;  Yang, Chenghua;  Gao, Xiaofeng;  Hou, Jianguo;  Wang, Linhui;  Yang, Bo;  Yang, Qing;  Ye, Huamao;  Zhou, Tie;  Lu, Xin;  Wang, Yan;  Qu, Min;  Yang, Qingsong;  Zhang, Wenhui;  Shah, Nakul M.;  Pehrsson, Erica C.;  Wang, Shuo;  Wang, Zengjun;  Jiang, Jun;  Zhu, Yan;  Chen, Rui;  Chen, Huan;  Zhu, Feng;  Lian, Bijun;  Li, Xiaoyun;  Zhang, Yun;  Wang, Chao;  Wang, Yue;  Xiao, Guangan;  Jiang, Junfeng;  Yang, Yue;  Liang, Chaozhao;  Hou, Jianquan;  Han, Conghui;  Chen, Ming;  Jiang, Ning;  Zhang, Dahong;  Wu, Song;  Yang, Jinjian;  Wang, Tao;  Chen, Yongliang;  Cai, Jiantong;  Yang, Wenzeng;  Xu, Jun;  Wang, Shaogang;  Gao, Xu;  Wang, Ting;  Sun, Yinghao
收藏  |  浏览/下载:18/0  |  提交时间:2020/07/03
A lysosomal switch triggers proteostasis renewal in the immortal C. elegans germ lineage (vol 551, pg 629, 2017) 期刊论文
NATURE, 2020, 580 (7802) : E5-E5
作者:  Lu, Zhihao;  Zou, Jianling;  Li, Shuang;  Topper, Michael J.;  Tao, Yong;  Zhang, Hao;  Jiao, Xi;  Xie, Wenbing;  Kong, Xiangqian;  Vaz, Michelle;  Li, Huili;  Cai, Yi;  Xia, Limin;  Huang, Peng;  Rodgers, Kristen;  Lee, Beverly;  Riemer, Joanne B.;  Day, Chi-Ping;  Yen, Ray-Whay Chiu;  Cui, Ying;  Wang, Yujiao;  Wang, Yanni;  Zhang, Weiqiang;  Easwaran, Hariharan;  Hulbert, Alicia;  Kim, KiBem;  Juergens, Rosalyn A.;  Yang, Stephen C.;  Battafarano, Richard J.;  Bush, Errol L.;  Broderick, Stephen R.;  Cattaneo, Stephen M.;  Brahmer, Julie R.;  Rudin, Charles M.;  Wrangle, John;  Mei, Yuping;  Kim, Young J.;  Zhang, Bin;  Wang, Ken Kang-Hsin;  Forde, Patrick M.;  Margolick, Joseph B.;  Nelkin, Barry D.;  Zahnow, Cynthia A.;  Pardoll, Drew M.;  Housseau, Franck;  Baylin, Stephen B.;  Shen, Lin;  Brock, Malcolm V.
收藏  |  浏览/下载:26/0  |  提交时间:2020/07/03
Nightside condensation of iron in an ultrahot giant exoplanet 期刊论文
NATURE, 2020, 580 (7805) : 597-+
作者:  Lu, Zhihao;  Zou, Jianling;  Li, Shuang;  Topper, Michael J.;  Tao, Yong;  Zhang, Hao;  Jiao, Xi;  Xie, Wenbing;  Kong, Xiangqian;  Vaz, Michelle;  Li, Huili;  Cai, Yi;  Xia, Limin;  Huang, Peng;  Rodgers, Kristen;  Lee, Beverly;  Riemer, Joanne B.;  Day, Chi-Ping;  Yen, Ray-Whay Chiu;  Cui, Ying;  Wang, Yujiao;  Wang, Yanni;  Zhang, Weiqiang;  Easwaran, Hariharan;  Hulbert, Alicia;  Kim, KiBem;  Juergens, Rosalyn A.;  Yang, Stephen C.;  Battafarano, Richard J.;  Bush, Errol L.;  Broderick, Stephen R.;  Cattaneo, Stephen M.;  Brahmer, Julie R.;  Rudin, Charles M.;  Wrangle, John;  Mei, Yuping;  Kim, Young J.;  Zhang, Bin;  Wang, Ken Kang-Hsin;  Forde, Patrick M.;  Margolick, Joseph B.;  Nelkin, Barry D.;  Zahnow, Cynthia A.;  Pardoll, Drew M.;  Housseau, Franck;  Baylin, Stephen B.;  Shen, Lin;  Brock, Malcolm V.
收藏  |  浏览/下载:57/0  |  提交时间:2020/07/03

Ultrahot giant exoplanets receive thousands of times Earth'  s insolation(1,2). Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry(3-5). Daysides are predicted to be cloud-free, dominated by atomic species(6) and much hotter than nightsides(5,7,8). Atoms are expected to recombine into molecules over the nightside(9), resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed(10-14), no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ('  evening'  ) and night-to-day ('  morning'  ) terminators could, however, be revealed as an asymmetric absorption signature during transit(4,7,15). Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11 +/- 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside(16). In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.


Absorption lines of iron in the dayside atmosphere of an ultrahot giant exoplanet disappear after travelling across the nightside, showing that the iron has condensed during its travel.


  
Structural insight into arenavirus replication machinery 期刊论文
NATURE, 2020, 579 (7800) : 615-+
作者:  Zhang, Xiaheng;  Smith, Russell T.;  Le, Chip;  McCarver, Stefan J.;  Shireman, Brock T.;  Carruthers, Nicholas I.;  MacMillan, David W. C.
收藏  |  浏览/下载:19/0  |  提交时间:2020/07/03

The authors provide high-resolution structures of two arenavirus polymerases, revealing that the active site of arenavirus polymerase is inherently switched on, without the requirement for allosteric activation by 5 '  -viral RNA, and that dimerization facilitates polymerase activity.


Arenaviruses can cause severe haemorrhagic fever and neurological diseases in humans and other animals, exemplified by Lassa mammarenavirus, Machupo mammarenavirus and lymphocytic choriomeningitis virus, posing great threats to public health(1-4). These viruses encode a large multi-domain RNA-dependent RNA polymerase for transcription and replication of the viral genome(5). Viral polymerases are one of the leading antiviral therapeutic targets. However, the structure of arenavirus polymerase is not yet known. Here we report the near-atomic resolution structures of Lassa and Machupo virus polymerases in both apo and promoter-bound forms. These structures display a similar overall architecture to influenza virus and bunyavirus polymerases but possess unique local features, including an arenavirus-specific insertion domain that regulates the polymerase activity. Notably, the ordered active site of arenavirus polymerase is inherently switched on, without the requirement for allosteric activation by 5 '  -viral RNA, which is a necessity for both influenza virus and bunyavirus polymerases(6,7). Moreover, dimerization could facilitate the polymerase activity. These findings advance our understanding of the mechanism of arenavirus replication and provide an important basis for developing antiviral therapeutics.


  
Neuronal programming by microbiota regulates intestinal physiology 期刊论文
NATURE, 2020, 578 (7794) : 284-+
作者:  Li, Yilong;  Roberts, Nicola D.;  Wala, Jeremiah A.;  Shapira, Ofer;  Schumacher, Steven E.;  Kumar, Kiran;  Khurana, Ekta;  Waszak, Sebastian;  Korbel, Jan O.;  Haber, James E.;  Imielinski, Marcin;  Weischenfeldt, Joachim;  Beroukhim, Rameen;  Campbell, Peter J.;  Akdemir, Kadir C.;  Alvarez, Eva G.;  Baez-Ortega, Adrian;  Boutros, Paul C.;  Bowtell, David D. L.;  Brors, Benedikt;  Burns, Kathleen H.;  Chan, Kin;  Chen, Ken;  Cortes-Ciriano, Isidro;  Dueso-Barroso, Ana;  Dunford, Andrew J.;  Edwards, Paul A.;  Estivill, Xavier;  Etemadmoghadam, Dariush;  Feuerbach, Lars;  Fink, J. Lynn;  Frenkel-Morgenstern, Milana;  Garsed, Dale W.;  Gerstein, Mark;  Gordenin, Dmitry A.;  Haan, David;  Hess, Julian M.;  Hutter, Barbara;  Jones, David T. W.;  Ju, Young Seok;  Kazanov, Marat D.;  Klimczak, Leszek J.;  Koh, Youngil;  Lee, Eunjung Alice;  Lee, Jake June-Koo;  Lynch, Andy G.;  Macintyre, Geoff;  Markowetz, Florian;  Martincorena, Inigo;  Martinez-Fundichely, Alexander;  Meyerson, Matthew;  Miyano, Satoru;  Nakagawa, Hidewaki;  Navarro, Fabio C. P.;  Ossowski, Stephan;  Park, Peter J.;  Pearson, John, V;  Puiggros, Montserrat;  Rippe, Karsten;  Roberts, Steven A.;  Rodriguez-Martin, Bernardo;  Scully, Ralph;  Shackleton, Mark;  Sidiropoulos, Nikos;  Sieverling, Lina;  Stewart, Chip;  Torrents, David;  Tubio, Jose M. C.;  Villasante, Izar;  Waddell, Nicola;  Yang, Lixing;  Yao, Xiaotong;  Yoon, Sung-Soo;  Zamora, Jorge;  Zhang, Cheng-Zhong
收藏  |  浏览/下载:38/0  |  提交时间:2020/07/03

Neural control of the function of visceral organs is essential for homeostasis and health. Intestinal peristalsis is critical for digestive physiology and host defence, and is often dysregulated in gastrointestinal disorders(1). Luminal factors, such as diet and microbiota, regulate neurogenic programs of gut motility(2-5), but the underlying molecular mechanisms remain unclear. Here we show that the transcription factor aryl hydrocarbon receptor (AHR) functions as a biosensor in intestinal neural circuits, linking their functional output to the microbial environment of the gut lumen. Using nuclear RNA sequencing of mouse enteric neurons that represent distinct intestinal segments and microbiota states, we demonstrate that the intrinsic neural networks of the colon exhibit unique transcriptional profiles that are controlled by the combined effects of host genetic programs and microbial colonization. Microbiota-induced expression of AHR in neurons of the distal gastrointestinal tract enables these neurons to respond to the luminal environment and to induce expression of neuron-specific effector mechanisms. Neuron-specific deletion of Ahr, or constitutive overexpression of its negative feedback regulator CYP1A1, results in reduced peristaltic activity of the colon, similar to that observed in microbiota-depleted mice. Finally, expression of Ahr in the enteric neurons of mice treated with antibiotics partially restores intestinal motility. Together, our experiments identify AHR signalling in enteric neurons as a regulatory node that integrates the luminal environment with the physiological output of intestinal neural circuits to maintain gut homeostasis and health.


In a mouse model, aryl hydrocarbon receptor signalling in enteric neurons is revealed as a mechanism that helps to maintain gut homeostasis by integrating the luminal environment with the physiology of intestinal neural circuits.