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61.
DNA repair protein Ku80 suppresses chromosomal aberrations and malignant transformation 总被引:33,自引:0,他引:33
Difilippantonio MJ Zhu J Chen HT Meffre E Nussenzweig MC Max EE Ried T Nussenzweig A 《Nature》2000,404(6777):510-514
Cancer susceptibility genes have been classified into two groups: gatekeepers and caretakers. Gatekeepers are genes that control cell proliferation and death, whereas caretakers are DNA repair genes whose inactivation leads to genetic instability. Abrogation of both caretaker and gatekeeper function markedly increases cancer susceptibility. Although the importance of Ku80 in DNA double-strand break repair is well established, neither Ku80 nor other components of the non-homologous end-joining pathway are known to have a caretaker role in maintaining genomic stability. Here we show that mouse cells deficient for Ku80 display a marked increase in chromosomal aberrations, including breakage, translocations and aneuploidy. Despite the observed chromosome instabilities, Ku80-/- mice have only a slightly earlier onset of cancer. Loss of p53 synergizes with Ku80 to promote tumorigenesis such that all Ku80-/- p53-/- mice succumb to disseminated pro-B-cell lymphoma before three months of age. Tumours result from a specific set of chromosomal translocations and gene amplifications involving IgH and c-Myc, reminiscent of Burkitt's lymphoma. We conclude that Ku80 is a caretaker gene that maintains the integrity of the genome by a mechanism involving the suppression of chromosomal rearrangements. 相似文献
62.
郯庐断裂带形成演化的年代学研究 总被引:28,自引:0,他引:28
通过对郯庐断裂带东侧张八岭蓝片岩带内白云母^40Ar-^39Ar年龄、断裂带内片麻状花岗岩中钾长石^40Ar-^39Ar年龄以及断裂带内断层泥K-Ar、ESR年龄的测定,并结合有关的地质和古地磁资料,厘定了籽庐断裂带形成和演化的过程:(1)三叠纪(244~209Ma)由于华北与扬子地块碰撞,郯庐断裂带形成为其主要左行平稳时期;(2)侏罗纪(189~164Ma)时郯庐断裂东侧下扬子地块可能经历了逆时 相似文献
63.
The transmembrane glycoprotein CD98 is a potential regulator of multiple functions, including integrin signaling and amino acid transport. Abnormal expression or function of CD98 and disruption of the interactions between CD98 and its binding partners result in defects in cell homeostasis and immune responses. Indeed, expression of CD98 has been correlated with diseases such as inflammation and tumor metastasis. Modulation of CD98 expression and/or function therefore represents a promising therapeutic strategy for the treatment and prevention of such pathologies. Herein, we review the role of CD98 with focus on its functional importance in homeostasis and immune responses, which could help to better understand the pathogenesis of CD98-associated diseases. 相似文献
64.
Rafnar T Gudbjartsson DF Sulem P Jonasdottir A Sigurdsson A Jonasdottir A Besenbacher S Lundin P Stacey SN Gudmundsson J Magnusson OT le Roux L Orlygsdottir G Helgadottir HT Johannsdottir H Gylfason A Tryggvadottir L Jonasson JG de Juan A Ortega E Ramon-Cajal JM García-Prats MD Mayordomo C Panadero A Rivera F Aben KK van Altena AM Massuger LF Aavikko M Kujala PM Staff S Aaltonen LA Olafsdottir K Bjornsson J Kong A Salvarsdottir A Saemundsson H Olafsson K Benediktsdottir KR Gulcher J Masson G 《Nature genetics》2011,43(11):1104-1107
Ovarian cancer causes more deaths than any other gynecologic malignancy in developed countries. Sixteen million sequence variants, identified through whole-genome sequencing of 457 Icelanders, were imputed to 41,675 Icelanders genotyped using SNP chips, as well as to their relatives. Sequence variants were tested for association with ovarian cancer (N of affected individuals = 656). We discovered a rare (0.41% allelic frequency) frameshift mutation, c.2040_2041insTT, in the BRIP1 (FANCJ) gene that confers an increase in ovarian cancer risk (odds ratio (OR) = 8.13, P = 2.8 × 10(-14)). The mutation was also associated with increased risk of cancer in general and reduced lifespan by 3.6 years. In a Spanish population, another frameshift mutation in BRIP1, c.1702_1703del, was seen in 2 out of 144 subjects with ovarian cancer and 1 out of 1,780 control subjects (P = 0.016). This allele was also associated with breast cancer (seen in 6/927 cases; P = 0.0079). Ovarian tumors from heterozygous carriers of the Icelandic mutation show loss of the wild-type allele, indicating that BRIP1 behaves like a classical tumor suppressor gene in ovarian cancer. 相似文献
65.
Bowman AB Lam YC Jafar-Nejad P Chen HK Richman R Samaco RC Fryer JD Kahle JJ Orr HT Zoghbi HY 《Nature genetics》2007,39(3):373-379
Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by expansion of a glutamine tract in ataxin-1 (ATXN1). SCA1 pathogenesis studies support a model in which the expanded glutamine tract causes toxicity by modulating the normal activities of ATXN1. To explore native interactions that modify the toxicity of ATXN1, we generated a targeted duplication of the mouse ataxin-1-like (Atxn1l, also known as Boat) locus, a highly conserved paralog of SCA1, and tested the role of this protein in SCA1 pathology. Using a knock-in mouse model of SCA1 that recapitulates the selective neurodegeneration seen in affected individuals, we found that elevated Atxn1l levels suppress neuropathology by displacing mutant Atxn1 from its native complex with Capicua (CIC). Our results provide genetic evidence that the selective neuropathology of SCA1 arises from modulation of a core functional activity of ATXN1, and they underscore the importance of studying the paralogs of genes mutated in neurodegenerative diseases to gain insight into mechanisms of pathogenesis. 相似文献
66.
O'Donovan MC Craddock N Norton N Williams H Peirce T Moskvina V Nikolov I Hamshere M Carroll L Georgieva L Dwyer S Holmans P Marchini JL Spencer CC Howie B Leung HT Hartmann AM Möller HJ Morris DW Shi Y Feng G Hoffmann P Propping P Vasilescu C Maier W Rietschel M Zammit S Schumacher J Quinn EM Schulze TG Williams NM Giegling I Iwata N Ikeda M Darvasi A Shifman S He L Duan J Sanders AR Levinson DF Gejman PV Cichon S Nöthen MM Gill M Corvin A Rujescu D Kirov G Owen MJ Buccola NG Mowry BJ 《Nature genetics》2008,40(9):1053-1055
We carried out a genome-wide association study of schizophrenia (479 cases, 2,937 controls) and tested loci with P < 10(-5) in up to 16,726 additional subjects. Of 12 loci followed up, 3 had strong independent support (P < 5 x 10(-4)), and the overall pattern of replication was unlikely to occur by chance (P = 9 x 10(-8)). Meta-analysis provided strongest evidence for association around ZNF804A (P = 1.61 x 10(-7)) and this strengthened when the affected phenotype included bipolar disorder (P = 9.96 x 10(-9)). 相似文献
67.
Electronic spin transport and spin precession in single graphene layers at room temperature 总被引:1,自引:0,他引:1
Electronic transport in single or a few layers of graphene is the subject of intense interest at present. The specific band structure of graphene, with its unique valley structure and Dirac neutrality point separating hole states from electron states, has led to the observation of new electronic transport phenomena such as anomalously quantized Hall effects, absence of weak localization and the existence of a minimum conductivity. In addition to dissipative transport, supercurrent transport has also been observed. Graphene might also be a promising material for spintronics and related applications, such as the realization of spin qubits, owing to the low intrinsic spin orbit interaction, as well as the low hyperfine interaction of the electron spins with the carbon nuclei. Here we report the observation of spin transport, as well as Larmor spin precession, over micrometre-scale distances in single graphene layers. The 'non-local' spin valve geometry was used in these experiments, employing four-terminal contact geometries with ferromagnetic cobalt electrodes making contact with the graphene sheet through a thin oxide layer. We observe clear bipolar (changing from positive to negative sign) spin signals that reflect the magnetization direction of all four electrodes, indicating that spin coherence extends underneath all of the contacts. No significant changes in the spin signals occur between 4.2 K, 77 K and room temperature. We extract a spin relaxation length between 1.5 and 2 mum at room temperature, only weakly dependent on charge density. The spin polarization of the ferromagnetic contacts is calculated from the measurements to be around ten per cent. 相似文献
68.
69.
改变固/液界面润湿性提高原油采收率的实验室研究 总被引:11,自引:0,他引:11
利用改进的Washburn方程测量固体粉末的润湿性,研究了十二烷基苯磺酸钠(SDBS)水溶液在硅胶及高岭土两种固体粉末表面上引起的润湿性变化,用荧光猝灭法测定了SDBS在水溶液里的胶束平均聚集数。探讨了十二烷基苯磺酸钠水溶液在固体粉开表面的润湿性,表面活性剂的临界胶束浓度(CMC)与表面含油粉末脱油率的关系,对在非超低界面张力条件下,通过改变固/液界面润湿性提高原油采收率作了实验探讨。 相似文献
70.
Gudmundsson J Sulem P Gudbjartsson DF Jonasson JG Masson G He H Jonasdottir A Sigurdsson A Stacey SN Johannsdottir H Helgadottir HT Li W Nagy R Ringel MD Kloos RT de Visser MC Plantinga TS den Heijer M Aguillo E Panadero A Prats E Garcia-Castaño A De Juan A Rivera F Walters GB Bjarnason H Tryggvadottir L Eyjolfsson GI Bjornsdottir US Holm H Olafsson I Kristjansson K Kristvinsson H Magnusson OT Thorleifsson G Gulcher JR Kong A Kiemeney LA Jonsson T Hjartarson H Mayordomo JI Netea-Maier RT 《Nature genetics》2012,44(3):319-322
To search for sequence variants conferring risk of nonmedullary thyroid cancer, we focused our analysis on 22 SNPs with a P < 5 × 10(-8) in a genome-wide association study on levels of thyroid stimulating hormone (TSH) in 27,758 Icelanders. Of those, rs965513 has previously been shown to associate with thyroid cancer. The remaining 21 SNPs were genotyped in 561 Icelandic individuals with thyroid cancer (cases) and up to 40,013 controls. Variants suggestively associated with thyroid cancer (P < 0.05) were genotyped in an additional 595 non-Icelandic cases and 2,604 controls. After combining the results, three variants were shown to associate with thyroid cancer: rs966423 on 2q35 (OR = 1.34; P(combined) = 1.3 × 10(-9)), rs2439302 on 8p12 (OR = 1.36; P(combined) = 2.0 × 10(-9)) and rs116909374 on 14q13.3 (OR = 2.09; P(combined) = 4.6 × 10(-11)), a region previously reported to contain an uncorrelated variant conferring risk of thyroid cancer. A strong association (P = 9.1 × 10(-91)) was observed between rs2439302 on 8p12 and expression of NRG1, which encodes the signaling protein neuregulin 1, in blood. 相似文献