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21.
Long-term proliferation of mouse primordial germ cells in culture. 总被引:70,自引:0,他引:70
Primordial germ cells (PGCs) are first identifiable as a population of about eight alkaline phosphatase-positive cells in the 7.0 days postcoitum mouse embryo. During the next 6 days of development they proliferate to give rise to the 25,000 cells that will establish the meiotic population. Steel factor is required for PGC survival both in vivo and in vitro and together with leukaemia inhibitory factor stimulates PGC proliferation in vitro. In feeder-dependent culture, PGCs will proliferate for up to 7 days, but their numbers eventually decline and their proliferative capacity is only a fraction of that seen in vivo. Here we report a further factor that stimulates PGC proliferation in vitro, basic fibroblast growth factor (bFGF). Furthermore, bFGF, in the presence of steel factor and leukaemia inhibitory factor, stimulates long-term proliferation of PGCs, leading to the derivation of large colonies of cells. These embryonic germ cells resemble embryonic stem cells, pluripotent cells derived from preimplantation embryos, or feeder-dependent embryonal carcinoma cells, pluripotent stem cells of PGC-derived tumours (teratomas and teratocarcinomas). To our knowledge, these results provide the first system for long-term culture of PGCs. 相似文献
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Positional cloning of zebrafish ferroportin1 identifies a conserved vertebrate iron exporter 总被引:81,自引:0,他引:81
Donovan A Brownlie A Zhou Y Shepard J Pratt SJ Moynihan J Paw BH Drejer A Barut B Zapata A Law TC Brugnara C Lux SE Pinkus GS Pinkus JL Kingsley PD Palis J Fleming MD Andrews NC Zon LI 《Nature》2000,403(6771):776-781
Defects in iron absorption and utilization lead to iron deficiency and overload disorders. Adult mammals absorb iron through the duodenum, whereas embryos obtain iron through placental transport. Iron uptake from the intestinal lumen through the apical surface of polarized duodenal enterocytes is mediated by the divalent metal transporter, DMTi. A second transporter has been postulated to export iron across the basolateral surface to the circulation. Here we have used positional cloning to identify the gene responsible for the hypochromic anaemia of the zebrafish mutant weissherbst. The gene, ferroportin1, encodes a multiple-transmembrane domain protein, expressed in the yolk sac, that is a candidate for the elusive iron exporter. Zebrafish ferroportin1 is required for the transport of iron from maternally derived yolk stores to the circulation and functions as an iron exporter when expressed in Xenopus oocytes. Human Ferroportin1 is found at the basal surface of placental syncytiotrophoblasts, suggesting that it also transports iron from mother to embryo. Mammalian Ferroportin1 is expressed at the basolateral surface of duodenal enterocytes and could export cellular iron into the circulation. We propose that Ferroportin1 function may be perturbed in mammalian disorders of iron deficiency or overload. 相似文献
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Kote-Jarai Z Olama AA Giles GG Severi G Schleutker J Weischer M Campa D Riboli E Key T Gronberg H Hunter DJ Kraft P Thun MJ Ingles S Chanock S Albanes D Hayes RB Neal DE Hamdy FC Donovan JL Pharoah P Schumacher F Henderson BE Stanford JL Ostrander EA Sorensen KD Dörk T Andriole G Dickinson JL Cybulski C Lubinski J Spurdle A Clements JA Chambers S Aitken J Gardiner RA Thibodeau SN Schaid D John EM Maier C Vogel W Cooney KA Park JY Cannon-Albright L Brenner H Habuchi T Zhang HW Lu YJ Kaneva R 《Nature genetics》2011,43(8):785-791
Prostate cancer (PrCa) is the most frequently diagnosed male cancer in developed countries. We conducted a multi-stage genome-wide association study for PrCa and previously reported the results of the first two stages, which identified 16 PrCa susceptibility loci. We report here the results of stage 3, in which we evaluated 1,536 SNPs in 4,574 individuals with prostate cancer (cases) and 4,164 controls. We followed up ten new association signals through genotyping in 51,311 samples in 30 studies from the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium. In addition to replicating previously reported loci, we identified seven new prostate cancer susceptibility loci on chromosomes 2p11, 3q23, 3q26, 5p12, 6p21, 12q13 and Xq12 (P = 4.0 × 10(-8) to P = 2.7 × 10(-24)). We also identified a SNP in TERT more strongly associated with PrCa than that previously reported. More than 40 PrCa susceptibility loci, explaining ~25% of the familial risk in this disease, have now been identified. 相似文献
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Eeles RA Kote-Jarai Z Giles GG Olama AA Guy M Jugurnauth SK Mulholland S Leongamornlert DA Edwards SM Morrison J Field HI Southey MC Severi G Donovan JL Hamdy FC Dearnaley DP Muir KR Smith C Bagnato M Ardern-Jones AT Hall AL O'Brien LT Gehr-Swain BN Wilkinson RA Cox A Lewis S Brown PM Jhavar SG Tymrakiewicz M Lophatananon A Bryant SL;UK Genetic Prostate Cancer Study Collaborators;British Association of Urological Surgeons' Section of Oncology;UK ProtecT Study Collaborators Horwich A Huddart RA 《Nature genetics》2008,40(3):316-321
Prostate cancer is the most common cancer affecting males in developed countries. It shows consistent evidence of familial aggregation, but the causes of this aggregation are mostly unknown. To identify common alleles associated with prostate cancer risk, we conducted a genome-wide association study (GWAS) using blood DNA samples from 1,854 individuals with clinically detected prostate cancer diagnosed at =60 years or with a family history of disease, and 1,894 population-screened controls with a low prostate-specific antigen (PSA) concentration (<0.5 ng/ml). We analyzed these samples for 541,129 SNPs using the Illumina Infinium platform. Initial putative associations were confirmed using a further 3,268 cases and 3,366 controls. We identified seven loci associated with prostate cancer on chromosomes 3, 6, 7, 10, 11, 19 and X (P = 2.7 x 10(-8) to P = 8.7 x 10(-29)). We confirmed previous reports of common loci associated with prostate cancer at 8q24 and 17q. Moreover, we found that three of the newly identified loci contain candidate susceptibility genes: MSMB, LMTK2 and KLK3. 相似文献
25.
Systems Thinking and Higher Education: The Vanguard Method 总被引:1,自引:1,他引:0
Reforms to the higher education sector in the UK are only increasing competitive pressures between institutions. Universities are therefore looking to gain competitive advantage over their rivals both in terms of student experience and through administrative efficiency. This paper will present an alternative view of how to transform the way that the higher education system delivers service to students in an environment where ‘student choice’ will be viewed as of paramount importance. The paper will argue that the prevailing ‘command and control’ (Seddon 2003) management logic, which can be found at work throughout both the public and private sectors, is the primary cause of inferior, expensive service. As an alternative, this paper will explore the benefits of working in a systems thinking way, whilst comparing and contrasting this with the flawed thinking which currently prevails. The Vanguard Method (Seddon 2008) is one particular form of systems thinking which has been developed for use in service organisations (Jackson et al. 2008) and which has been applied to many public sector organisations (ODPM 2005; Middleton 2010; Zokaei et al. 2010). Using a case study methodology (Yin 2009), this paper will address what has been learnt by applying the Vanguard Method in an HEI environment for the first time. 相似文献
26.
Shaw GC Cope JJ Li L Corson K Hersey C Ackermann GE Gwynn B Lambert AJ Wingert RA Traver D Trede NS Barut BA Zhou Y Minet E Donovan A Brownlie A Balzan R Weiss MJ Peters LL Kaplan J Zon LI Paw BH 《Nature》2006,440(7080):96-100
Iron has a fundamental role in many metabolic processes, including electron transport, deoxyribonucleotide synthesis, oxygen transport and many essential redox reactions involving haemoproteins and Fe-S cluster proteins. Defective iron homeostasis results in either iron deficiency or iron overload. Precise regulation of iron transport in mitochondria is essential for haem biosynthesis, haemoglobin production and Fe-S cluster protein assembly during red cell development. Here we describe a zebrafish mutant, frascati (frs), that shows profound hypochromic anaemia and erythroid maturation arrest owing to defects in mitochondrial iron uptake. Through positional cloning, we show that the gene mutated in the frs mutant is a member of the vertebrate mitochondrial solute carrier family (SLC25) that we call mitoferrin (mfrn). mfrn is highly expressed in fetal and adult haematopoietic tissues of zebrafish and mouse. Erythroblasts generated from murine embryonic stem cells null for Mfrn (also known as Slc25a37) show maturation arrest with severely impaired incorporation of 55Fe into haem. Disruption of the yeast mfrn orthologues, MRS3 and MRS4, causes defects in iron metabolism and mitochondrial Fe-S cluster biogenesis. Murine Mfrn rescues the defects in frs zebrafish, and zebrafish mfrn complements the yeast mutant, indicating that the function of the gene may be highly conserved. Our data show that mfrn functions as the principal mitochondrial iron importer essential for haem biosynthesis in vertebrate erythroblasts. 相似文献
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Yoon JC Puigserver P Chen G Donovan J Wu Z Rhee J Adelmant G Stafford J Kahn CR Granner DK Newgard CB Spiegelman BM 《Nature》2001,413(6852):131-138