排序方式: 共有71条查询结果,搜索用时 187 毫秒
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Bender A Krishnan KJ Morris CM Taylor GA Reeve AK Perry RH Jaros E Hersheson JS Betts J Klopstock T Taylor RW Turnbull DM 《Nature genetics》2006,38(5):515-517
Here we show that in substantia nigra neurons from both aged controls and individuals with Parkinson disease, there is a high level of deleted mitochondrial DNA (mtDNA) (controls, 43.3% +/- 9.3%; individuals with Parkinson disease, 52.3% +/- 9.3%). These mtDNA mutations are somatic, with different clonally expanded deletions in individual cells, and high levels of these mutations are associated with respiratory chain deficiency. Our studies suggest that somatic mtDNA deletions are important in the selective neuronal loss observed in brain aging and in Parkinson disease. 相似文献
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CpG island methylator phenotype underlies sporadic microsatellite instability and is tightly associated with BRAF mutation in colorectal cancer 总被引:19,自引:0,他引:19
Weisenberger DJ Siegmund KD Campan M Young J Long TI Faasse MA Kang GH Widschwendter M Weener D Buchanan D Koh H Simms L Barker M Leggett B Levine J Kim M French AJ Thibodeau SN Jass J Haile R Laird PW 《Nature genetics》2006,38(7):787-793
Aberrant DNA methylation of CpG islands has been widely observed in human colorectal tumors and is associated with gene silencing when it occurs in promoter areas. A subset of colorectal tumors has an exceptionally high frequency of methylation of some CpG islands, leading to the suggestion of a distinct trait referred to as 'CpG island methylator phenotype', or 'CIMP'. However, the existence of CIMP has been challenged. To resolve this continuing controversy, we conducted a systematic, stepwise screen of 195 CpG island methylation markers using MethyLight technology, involving 295 primary human colorectal tumors and 16,785 separate quantitative analyses. We found that CIMP-positive (CIMP+) tumors convincingly represent a distinct subset, encompassing almost all cases of tumors with BRAF mutation (odds ratio = 203). Sporadic cases of mismatch repair deficiency occur almost exclusively as a consequence of CIMP-associated methylation of MLH1 . We propose a robust new marker panel to classify CIMP+ tumors. 相似文献
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FCGR3B copy number variation is associated with susceptibility to systemic, but not organ-specific, autoimmunity 总被引:13,自引:0,他引:13
Fanciulli M Norsworthy PJ Petretto E Dong R Harper L Kamesh L Heward JM Gough SC de Smith A Blakemore AI Froguel P Owen CJ Pearce SH Teixeira L Guillevin L Graham DS Pusey CD Cook HT Vyse TJ Aitman TJ 《Nature genetics》2007,39(6):721-723
Naturally occurring variation in gene copy number is increasingly recognized as a heritable source of susceptibility to genetically complex diseases. Here we report strong association between FCGR3B copy number and risk of systemic lupus erythematosus (P = 2.7 x 10(-8)), microscopic polyangiitis (P = 2.9 x 10(-4)) and Wegener's granulomatosis in two independent cohorts from the UK (P = 3 x 10(-3)) and France (P = 1.1 x 10(-4)). We did not observe this association in the organ-specific Graves' disease or Addison's disease. Our findings suggest that low FCGR3B copy number, and in particular complete FCGR3B deficiency, has a key role in the development of systemic autoimmunity. 相似文献
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Polyhydroxylated steroids are regulators of body shape and size in higher organisms. In metazoans, intracellular receptors recognize these molecules. Plants, however, perceive steroids at membranes, using the membrane-integral receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1). Here we report the structure of the Arabidopsis thaliana BRI1 ligand-binding domain, determined by X-ray diffraction at 2.5?? resolution. We find a superhelix of 25 twisted leucine-rich repeats (LRRs), an architecture that is strikingly different from the assembly of LRRs in animal Toll-like receptors. A 70-amino-acid island domain between LRRs 21 and 22 folds back into the interior of the superhelix to create a surface pocket for binding the plant hormone brassinolide. Known loss- and gain-of-function mutations map closely to the hormone-binding site. We propose that steroid binding to BRI1 generates a docking platform for a co-receptor that is required for receptor activation. Our findings provide insight into the activation mechanism of this highly expanded family of plant receptors that have essential roles in hormone, developmental and innate immunity signalling. 相似文献
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Ingrid Dahlman Iain A Eaves Roman Kosoy V Anne Morrison Joanne Heward Stephen C L Gough Amit Allahabadia Jayne A Franklyn Jaakko Tuomilehto Eva Tuomilehto-Wolf Francesco Cucca Cristian Guja Constantin Ionescu-Tirgoviste Helen Stevens Philippa Carr Sarah Nutland Patricia McKinney Julian P Shield William Wang Heather J Cordell Neil Walker John A Todd Patrick Concannon 《Nature genetics》2002,30(2):149-150
It is increasingly apparent that the identification of true genetic associations in common multifactorial disease will require studies comprising thousands rather than the hundreds of individuals employed to date. Using 2,873 families, we were unable to confirm a recently published association of the interleukin 12B gene in 422 type I diabetic families. These results emphasize the need for large datasets, small P values and independent replication if results are to be reliable. 相似文献
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Kers JA Wach MJ Krasnoff SB Widom J Cameron KD Bukhalid RA Gibson DM Crane BR Loria R 《Nature》2004,429(6987):79-82
Nitric oxide (NO) is a potent intercellular signal in mammals that mediates key aspects of blood pressure, hormone release, nerve transmission and the immune response of higher organisms. Proteins homologous to full-length mammalian nitric oxide synthases (NOSs) are found in lower multicellular organisms. Recently, genome sequencing has shown that some bacteria contain genes coding for truncated NOS proteins; this is consistent with reports of NOS-like activities in bacterial extracts. Biological functions for bacterial NOSs are unknown, but have been presumed to be analogous to their role in mammals. Here we describe a gene in the plant pathogen Streptomyces turgidiscabies that encodes a NOS homologue, and we reveal its role in nitrating a dipeptide phytotoxin required for plant pathogenicity. High similarity between bacterial NOSs indicates a general function in biosynthetic nitration; thus, bacterial NOSs constitute a new class of enzymes. Here we show that the primary function of Streptomyces NOS is radically different from that of mammalian NOS. Surprisingly, mammalian NO signalling and bacterial biosynthetic nitration share an evolutionary origin. 相似文献
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Zusammenfassung Ein qualitatives Verfahren zur papierchromatographischen Trennung von Fettsäuren und Derivaten liess sich zur quantitativen Bestimmung ausbauen. Die Methode hat eine Fehlergrenze von etwa ± 5% und ist unabhängig von den funktionellen Gruppen der Moleküle. Sie ist für gesättigte Di- und Triglyceride nicht direkt anwendbar.
This work has been supported by a research grant from the National Institutes of Health (P. H. S. 4226) and by the Hormel Foundation. Hormel Institute publication No. 143. 相似文献
This work has been supported by a research grant from the National Institutes of Health (P. H. S. 4226) and by the Hormel Foundation. Hormel Institute publication No. 143. 相似文献
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