排序方式: 共有283条查询结果,搜索用时 15 毫秒
21.
Tran Cong Tuoc Evangelos Pavlakis Marco Andreas Tylkowski Anastassia Stoykova 《Cellular and molecular life sciences : CMLS》2014,71(17):3199-3218
The mammalian neocortex is a sheet of cells covering the cerebrum that provides the structural basis for the perception of sensory inputs, motor output responses, cognitive function, and mental capacity of primates. Recent discoveries promote the concept that increased cortical surface size and thickness in phylogenetically advanced species is a result of an increased generation of neurons, a process that underlies higher cognitive and intellectual performance in higher primates and humans. Here, we review some of the advances in the field, focusing on the diversity of neocortical progenitors in different species and the cellular mechanisms of neurogenesis. We discuss recent views on intrinsic and extrinsic molecular determinants, including the role of epigenetic chromatin modifiers and microRNA, in the control of neuronal output in developing cortex and in the establishment of normal cortical architecture. 相似文献
22.
Elia J Glessner JT Wang K Takahashi N Shtir CJ Hadley D Sleiman PM Zhang H Kim CE Robison R Lyon GJ Flory JH Bradfield JP Imielinski M Hou C Frackelton EC Chiavacci RM Sakurai T Rabin C Middleton FA Thomas KA Garris M Mentch F Freitag CM Steinhausen HC Todorov AA Reif A Rothenberger A Franke B Mick EO Roeyers H Buitelaar J Lesch KP Banaschewski T Ebstein RP Mulas F Oades RD Sergeant J Sonuga-Barke E Renner TJ Romanos M Romanos J Warnke A Walitza S Meyer J Pálmason H Seitz C Loo SK Smalley SL 《Nature genetics》2012,44(1):78-84
Attention deficit hyperactivity disorder (ADHD) is a common, heritable neuropsychiatric disorder of unknown etiology. We performed a whole-genome copy number variation (CNV) study on 1,013 cases with ADHD and 4,105 healthy children of European ancestry using 550,000 SNPs. We evaluated statistically significant findings in multiple independent cohorts, with a total of 2,493 cases with ADHD and 9,222 controls of European ancestry, using matched platforms. CNVs affecting metabotropic glutamate receptor genes were enriched across all cohorts (P = 2.1 × 10(-9)). We saw GRM5 (encoding glutamate receptor, metabotropic 5) deletions in ten cases and one control (P = 1.36 × 10(-6)). We saw GRM7 deletions in six cases, and we saw GRM8 deletions in eight cases and no controls. GRM1 was duplicated in eight cases. We experimentally validated the observed variants using quantitative RT-PCR. A gene network analysis showed that genes interacting with the genes in the GRM family are enriched for CNVs in ~10% of the cases (P = 4.38 × 10(-10)) after correction for occurrence in the controls. We identified rare recurrent CNVs affecting glutamatergic neurotransmission genes that were overrepresented in multiple ADHD cohorts. 相似文献
23.
Thomae AW Baltin J Pich D Deutsch MJ Ravasz M Zeller K Gossen M Hammerschmidt W Schepers A 《Cellular and molecular life sciences : CMLS》2011,68(22):3741-3756
In eukaryotes, binding of the six-subunit origin recognition complex (ORC) to DNA provides an interactive platform for the
sequential assembly of pre-replicative complexes. This process licenses replication origins competent for the subsequent initiation
step. Here, we analyze the contribution of human Orc6, the smallest subunit of ORC, to DNA binding and pre-replicative complex
formation. We show that Orc6 not only interacts with Orc1–Orc5 but also with the initiation factor Cdc6. Biochemical and imaging
experiments reveal that this interaction is required for licensing DNA replication competent. Furthermore, we demonstrate
that Orc6 contributes to the interaction of ORC with the chaperone protein HMGA1a (high mobility group protein A1a). Binding
of human ORC to replication origins is not specified at the level of DNA sequence and the functional organization of origins
is poorly understood. We have identified HMGA1a as one factor that might direct ORC to AT-rich heterochromatic regions. The
systematic analysis of the interaction between ORC and HMGA1a revealed that Orc6 interacts with the acidic C-terminus of HMGA1a
and also with its AT-hooks. Both domains support autonomous replication if targeted to DNA templates. As such, Orc6 functions
at different stages of the replication initiation process. Orc6 can interact with ORC chaperone proteins such as HMGA1a to
facilitate chromatin binding of ORC and is also an essential factor for pre-RC formation. 相似文献
24.
Host defense peptides and proteins are important components of the innate host defense against pathogenic microorganisms.
They target negatively charged bacterial surfaces and disrupt microbial cytoplasmic membranes, which ultimately leads to bacterial
destruction. Throughout evolution, pathogens devised several mechanisms to protect themselves from deleterious damage of host
defense peptides. These strategies include (a) inactivation and cleavage of host defense peptides by production of host defense
binding proteins and proteases, (b) repulsion of the peptides by alteration of pathogen’s surface charge employing modifications
by amino acids or amino sugars of anionic molecules (e.g., teichoic acids, lipid A and phospholipids), (c) alteration of bacterial
membrane fluidity, and (d) expulsion of the peptides using multi drug pumps. Together with bacterial regulatory network(s)
that regulate expression and activity of these mechanisms, they represent attractive targets for development of novel antibacterials. 相似文献
25.
Fluctuations in the counting rate of photons originating from uncorrelated point sources become, within the coherently illuminated area, slightly enhanced compared to a random sequence of classical particles. This phenomenon, known in astronomy as the Hanbury Brown-Twiss effect, is a consequence of quantum interference between two indistinguishable photons and Bose Einstein statistics. The latter require that the composite bosonic wavefunction is a symmetric superposition of the two possible paths. For fermions, the corresponding two-particle wavefunction is antisymmetric: this excludes overlapping wave trains, which are forbidden by the Pauli exclusion principle. Here we use an electron field emitter to coherently illuminate two detectors, and find anticorrelations in the arrival times of the free electrons. The particle beam has low degeneracy (about 10(-4) electrons per cell in phase space); as such, our experiment represents the fermionic twin of the Hanbury Brown-Twiss effect for photons. 相似文献
26.
27.
Read TD Peterson SN Tourasse N Baillie LW Paulsen IT Nelson KE Tettelin H Fouts DE Eisen JA Gill SR Holtzapple EK Okstad OA Helgason E Rilstone J Wu M Kolonay JF Beanan MJ Dodson RJ Brinkac LM Gwinn M DeBoy RT Madpu R Daugherty SC Durkin AS Haft DH Nelson WC Peterson JD Pop M Khouri HM Radune D Benton JL Mahamoud Y Jiang L Hance IR Weidman JF Berry KJ Plaut RD Wolf AM Watkins KL Nierman WC Hazen A Cline R Redmond C Thwaite JE White O Salzberg SL Thomason B Friedlander AM Koehler TM Hanna PC 《Nature》2003,423(6935):81-86
Bacillus anthracis is an endospore-forming bacterium that causes inhalational anthrax. Key virulence genes are found on plasmids (extra-chromosomal, circular, double-stranded DNA molecules) pXO1 (ref. 2) and pXO2 (ref. 3). To identify additional genes that might contribute to virulence, we analysed the complete sequence of the chromosome of B. anthracis Ames (about 5.23 megabases). We found several chromosomally encoded proteins that may contribute to pathogenicity--including haemolysins, phospholipases and iron acquisition functions--and identified numerous surface proteins that might be important targets for vaccines and drugs. Almost all these putative chromosomal virulence and surface proteins have homologues in Bacillus cereus, highlighting the similarity of B. anthracis to near-neighbours that are not associated with anthrax. By performing a comparative genome hybridization of 19 B. cereus and Bacillus thuringiensis strains against a B. anthracis DNA microarray, we confirmed the general similarity of chromosomal genes among this group of close relatives. However, we found that the gene sequences of pXO1 and pXO2 were more variable between strains, suggesting plasmid mobility in the group. The complete sequence of B. anthracis is a step towards a better understanding of anthrax pathogenesis. 相似文献
28.
Kalscheuer VM Freude K Musante L Jensen LR Yntema HG Gécz J Sefiani A Hoffmann K Moser B Haas S Gurok U Haesler S Aranda B Nshedjan A Tzschach A Hartmann N Roloff TC Shoichet S Hagens O Tao J Van Bokhoven H Turner G Chelly J Moraine C Fryns JP Nuber U Hoeltzenbein M Scharff C Scherthan H Lenzner S Hamel BC Schweiger S Ropers HH 《Nature genetics》2003,35(4):313-315
We found mutations in the gene PQBP1 in 5 of 29 families with nonsyndromic (MRX) and syndromic (MRXS) forms of X-linked mental retardation (XLMR). Clinical features in affected males include mental retardation, microcephaly, short stature, spastic paraplegia and midline defects. PQBP1 has previously been implicated in the pathogenesis of polyglutamine expansion diseases. Our findings link this gene to XLMR and shed more light on the pathogenesis of this common disorder. 相似文献
29.
Convergent evolution of gene circuits 总被引:9,自引:0,他引:9
30.
Kohl I Bachmann L Mayer E Hallbrucker A Loerting T 《Nature》2005,435(7041):E1; discussion E1-E1; discussion E2
It has been unclear whether amorphous glassy water heated to around 140-150 K remains glassy until it crystallizes or whether instead it turns into a supercooled and very viscous liquid. Yue and Angell compare the behaviour of glassy water under these conditions to that of hyperquenched inorganic glasses, and claim that water stays glassy as it heats up to its crystallization point; they also find a 'hidden' glass-to-liquid transition at about 169 K. Here we use differential scanning calorimetry (DSC) heating to show that hyperquenched water deposited at 140 K behaves as an ultraviscous liquid, the limiting structure of which depends on the cooling rate--as predicted by theoretical analysis of the liquid-to-glass transition. Our findings are consistent with a glass-to-liquid transition-onset temperature (T(g)) in the region of 136 K (refs 3,4), and they indicate that measurements of the liquid's properties may clarify the anomalous properties of supercooled water. 相似文献