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排序方式: 共有367条查询结果,搜索用时 15 毫秒
91.
Rieger RM Ladurner P Hobmayer B Martindale MQ Finnerty JR 《Science (New York, N.Y.)》2005,307(5708):353-5; author reply 353-5
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Heaphy CM de Wilde RF Jiao Y Klein AP Edil BH Shi C Bettegowda C Rodriguez FJ Eberhart CG Hebbar S Offerhaus GJ McLendon R Rasheed BA He Y Yan H Bigner DD Oba-Shinjo SM Marie SK Riggins GJ Kinzler KW Vogelstein B Hruban RH Maitra A Papadopoulos N Meeker AK 《Science (New York, N.Y.)》2011,333(6041):425
The proteins encoded by ATRX and DAXX participate in chromatin remodeling at telomeres and other genomic sites. Because inactivating mutations of these genes are common in human pancreatic neuroendocrine tumors (PanNETs), we examined the telomere status of these tumors. We found that 61% of PanNETs displayed abnormal telomeres that are characteristic of a telomerase-independent telomere maintenance mechanism termed ALT (alternative lengthening of telomeres). All of the PanNETs exhibiting these abnormal telomeres had ATRX or DAXX mutations or loss of nuclear ATRX or DAXX protein. ATRX mutations also correlate with abnormal telomeres in tumors of the central nervous system. These data suggest that an alternative telomere maintenance function may operate in human tumors with alterations in the ATRX or DAXX genes. 相似文献
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The functional and anatomical rearrangements of cortical sensory maps accompanying changes in experience are not well understood. We examined in vivo and in vitro how the sensory map and underlying synaptic connectivity of the developing rat barrel cortex are altered when the sensory input to the cortex is partially deprived. In the nondeprived cortex, both the sensory responses and synaptic connectivity between columns were strengthened through an increase in the synaptic connection probability between L2/3 pyramids in adjacent columns. This was accompanied by a selective growth of L2/3pyramid axonal arbors between spared columns. In contrast, deprived and nondeprived cortical columns became weakly connected in their L2/3 pyramid connections. 相似文献
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Atomic force microscopy of an organic monolayer 总被引:2,自引:0,他引:2
O Marti H O Ribi B Drake T R Albrecht C F Quate P K Hansma 《Science (New York, N.Y.)》1988,239(4835):50-52
Atomic force microscope images of polymerized monolayers of n-(2-aminoethyl)-10,12-tricosadiynamide revealed parallel rows of molecules with a side-by-side spacing of approximately equal to 0.5 nanometer. Forces used for imaging (10(-8) newton) had no observable effect on the polymer strands. These results demonstrate that atomic force microscope images can be obtained for an organic system. 相似文献
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Bettegowda C Agrawal N Jiao Y Sausen M Wood LD Hruban RH Rodriguez FJ Cahill DP McLendon R Riggins G Velculescu VE Oba-Shinjo SM Marie SK Vogelstein B Bigner D Yan H Papadopoulos N Kinzler KW 《Science (New York, N.Y.)》2011,333(6048):1453-1455
Oligodendrogliomas are the second most common malignant brain tumor in adults and exhibit characteristic losses of chromosomes 1p and 19q. To identify the molecular genetic basis for this alteration, we performed exomic sequencing of seven tumors. Among other changes, we found that the CIC gene (homolog of the Drosophila gene capicua) on chromosome 19q was somatically mutated in six cases and that the FUBP1 gene [encoding far-upstream element (FUSE) binding protein] on chromosome 1p was somatically mutated in two tumors. Examination of 27 additional oligodendrogliomas revealed 12 and 3 more tumors with mutations of CIC and FUBP1, respectively, 58% of which were predicted to result in truncations of the encoded proteins. These results suggest a critical role for these genes in the biology and pathology of oligodendrocytes. 相似文献