排序方式: 共有28条查询结果,搜索用时 93 毫秒
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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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Cell-specific mitotic defect and dyserythropoiesis associated with erythroid band 3 deficiency 总被引:11,自引:0,他引:11
Paw BH Davidson AJ Zhou Y Li R Pratt SJ Lee C Trede NS Brownlie A Donovan A Liao EC Ziai JM Drejer AH Guo W Kim CH Gwynn B Peters LL Chernova MN Alper SL Zapata A Wickramasinghe SN Lee MJ Lux SE Fritz A Postlethwait JH Zon LI 《Nature genetics》2003,34(1):59-64
Most eukaryotic cell types use a common program to regulate the process of cell division. During mitosis, successful partitioning of the genetic material depends on spatially coordinated chromosome movement and cell cleavage. Here we characterize a zebrafish mutant, retsina (ret), that exhibits an erythroid-specific defect in cell division with marked dyserythropoiesis similar to human congenital dyserythropoietic anemia. Erythroblasts from ret fish show binuclearity and undergo apoptosis due to a failure in the completion of chromosome segregation and cytokinesis. Through positional cloning, we show that the ret mutation is in a gene (slc4a1) encoding the anion exchanger 1 (also called band 3 and AE1), an erythroid-specific cytoskeletal protein. We further show an association between deficiency in Slc4a1 and mitotic defects in the mouse. Rescue experiments in ret zebrafish embryos expressing transgenic slc4a1 with a variety of mutations show that the requirement for band 3 in normal erythroid mitosis is mediated through its protein 4.1R-binding domains. Our report establishes an evolutionarily conserved role for band 3 in erythroid-specific cell division and illustrates the concept of cell-specific adaptation for mitosis. 相似文献
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Di Bernardo MC Crowther-Swanepoel D Broderick P Webb E Sellick G Wild R Sullivan K Vijayakrishnan J Wang Y Pittman AM Sunter NJ Hall AG Dyer MJ Matutes E Dearden C Mainou-Fowler T Jackson GH Summerfield G Harris RJ Pettitt AR Hillmen P Allsup DJ Bailey JR Pratt G Pepper C Fegan C Allan JM Catovsky D Houlston RS 《Nature genetics》2008,40(10):1204-1210
We conducted a genome-wide association study of 299,983 tagging SNPs for chronic lymphocytic leukemia (CLL) and performed validation in two additional series totaling 1,529 cases and 3,115 controls. We identified six previously unreported CLL risk loci at 2q13 (rs17483466; P = 2.36 x 10(-10)), 2q37.1 (rs13397985, SP140; P = 5.40 x 10(-10)), 6p25.3 (rs872071, IRF4; P = 1.91 x 10(-20)), 11q24.1 (rs735665; P = 3.78 x 10(-12)), 15q23 (rs7176508; P = 4.54 x 10(-12)) and 19q13.32 (rs11083846, PRKD2; P = 3.96 x 10(-9)). These data provide the first evidence for the existence of common, low-penetrance susceptibility to a hematological malignancy and new insights into disease causation in CLL. 相似文献
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The budding yeast Saccharomyces cerevisiae has been used by humans for millennia to make wine, beer and bread. More recently, it became a key model organism for studies of eukaryotic biology and for genomic analysis. However, relatively little is known about the natural lifestyle and population genetics of yeast. One major question is whether genetically diverse yeast strains mate and recombine in the wild. We developed a method to infer the evolutionary history of a species from genome sequences of multiple individuals and applied it to whole-genome sequence data from three strains of Saccharomyces cerevisiae and the sister species Saccharomyces paradoxus. We observed a pattern of sequence variation among yeast strains in which ancestral recombination events lead to a mosaic of segments with shared genealogy. Based on sequence divergence and the inferred median size of shared segments (approximately 2,000 bp), we estimated that although any two strains have undergone approximately 16 million cell divisions since their last common ancestor, only 314 outcrossing events have occurred during this time (roughly one every 50,000 divisions). Local correlations in polymorphism rates indicate that linkage disequilibrium in yeast should extend over kilobases. Our results provide the initial foundation for population studies of association between genotype and phenotype in S. cerevisiae. 相似文献
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Pratt RF 《Cellular and molecular life sciences : CMLS》2008,65(14):2138-2155
The DD-peptidase enzymes (penicillin-binding proteins) catalyze the final transpeptidation reaction of bacterial cell wall (peptidoglycan) biosynthesis. Although there is now much structural information available about these enzymes, studies of their activity as enzymes lag. It is now established that representatives of two low-molecular-mass classes of DD-peptidases recognize elements of peptidoglycan structure and rapidly react with substrates and inhibitors incorporating these elements. No members of other DD-peptidase classes, including the high-molecular-mass enzymes, essential for bacterial growth, appear to interact strongly with any particular elements of peptidoglycan structure. Rational design of inhibitors for these enzymes is therefore challenging. 相似文献
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This paper attempts to illuminate Goethe's concept of an archetype by setting it alongside the concept of the self that was being articulated at the same time, also by writers of the Romantic movement. The Romantic concept of the self expresses a new concept of the self as a 'core' plus an expression of the core: and it is the same 'core plus expression' idea that is embodied in the Goethean archetype. Goethe's archetype is not simply a 'plan'. It is a kind of agent at the heart of a thing, striving for self expression, and to this end driving the thing's development. Both Romantic self and archetype reflect the wider attempt to reinstate the concept of action in our understanding of things and happenings in general. The root idea of there being at the heart of a living thing an agent pursuing a goal remains in the modern concept of the organism. 相似文献
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