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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iron is essential for many cellular functions; consequently, disturbances of iron homeostasis, leading to either iron deficiency or iron overload, can have significant clinical consequences. Despite the clinical prevalence of these disorders, the mechanism by which dietary iron is absorbed into the body is poorly understood. We have identified a key component in intestinal iron transport by study of the sex-linked anaemia (sla) mouse, which has a block in intestinal iron transport. Mice carrying the sla mutation develop moderate to severe microcytic hypochromic anaemia. Although these mice take up iron from the intestinal lumen into mature epithelial cells normally, the subsequent exit of iron into the circulation is diminished. As a result, iron accumulates in enterocytes and is lost during turnover of the intestinal epithelium. Biochemical studies have failed to identify the underlying difference between sla and normal mice, therefore, we used a genetic approach to identify the gene mutant in sla mice. We describe here a novel gene, Heph, encoding a transmembrane-bound ceruloplasmin homologue that is mutant in the sla mouse and highly expressed in intestine. We suggest that the hephaestin protein is a multicopper ferroxidase necessary for iron egress from intestinal enterocytes into the circulation and that it is an important link between copper and iron metabolism in mammals.
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PMID:Hephaestin, a ceruloplasmin homologue implicated in intestinal iron transport, is defective in the sla mouse. 998 72

Cyanobacteria are known to survive in iron-deficient environments, but the ways in which they acquire Fe and acclimate are not completely understood. Here we report a novel gene sll1263 that is required for Synechocystis sp. strain PCC 6803 to grow under iron-deficient conditions. sll1263 encodes a putative cation diffusion facilitator protein (CDF) that shows 50% amino acid similarity with ferrous iron efflux protein (FieF) of heterotrophic bacteria. In bacteria, the gene product is involved in metal export from the cell, but in Synechocystis sll1263 plays a role in iron uptake. The results show that expression of sll1263 was induced by iron-deficient conditions and its inactivation significantly decreased the growth rate of an sll1263(-) mutant. Other genes known to be required for Fe acquisition were also strongly up-regulated in the mutant even in the presence of high Fe. Overexpression of sll1263 increased growth under iron deficiency but reduced growth under high-iron stress, suggesting that the gene product was involved in iron uptake rather than detoxification. Expression of FieF in the sll1263(-) mutant was unable to rescue the Fe-deficient phenotype, but Sll1263 completely restored it. Measurements of cellular iron content and the iron uptake rate showed that they were significantly less in the sll1263(-) mutant than in the wild type, consistent with a role for sll1263 in iron uptake. We hypothesize that the low-iron habitats and high-iron requirements of cyanobacteria may be the reason why cyanobacterial CDF protein functions in Fe uptake and not efflux as in non-photosynthetic bacteria.
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PMID:Sll1263, a unique cation diffusion facilitator protein that promotes iron uptake in the cyanobacterium Synechocystis sp. Strain PCC 6803. 2268 83

Preliminary microarray analysis of cDNA from rice roots revealed an up-regulated transcript that was highly expressed in a five-day iron deficiency treatment. The entire sequence of this gene was determined by bioinformatics analysis. There were no proteins with significant levels of similarity detected in public databases. This novel gene with unknown biological function was designated as OsDPR (dwarf phenotype-related gene). We constructed a stable plant expression vector pCAMBIA1302-OsDPR::GFP and produced transgenic tobacco plants. The phenotypes suggested that OsDPR restrained the growth of transformed plants. To understand the mechanisms of this suppression effect, cell size and number were compared between transformants and wild-type plants. The cell proliferation rate was lower in OsDPR transgenic BY-2 cells than in wild-type cells, but OsDPR expression did not affect cell size. Moreover, the cell division-related gene CyclinD2.1, which is involved in plant growth, was down-regulated in transgenic tobacco plants. These findings suggested that the novel iron-regulated gene OsDPR is responsible for the nanism phenotype of transgenic seedlings because of the inhibition of plant cell proliferation.
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PMID:Overexpression of OsDPR, a novel rice gene highly expressed under iron deficiency, suppresses plant growth. 2323 23

Computational solutions enable plant scientists to model protein-mediated stress responses and characterize novel gene functions that coordinate responses to a variety of abiotic stress conditions. Recently, density functional theory was used to study proteins active sites and elucidate enzyme conversion mechanisms involved in iron deficiency responsive signaling pathways. Computational approaches for protein homology modeling and the kinetic modeling of signaling pathways have also resolved the identity and function in proteins involved in iron deficiency signaling pathways. Significant changes in gene relationships under other stress conditions, such as heat or drought stress, have been recently identified using differential network analysis, suggesting that stress tolerance is achieved through asynchronous control. Moreover, the increasing development and use of statistical modeling and systematic modeling of transcriptomic data have provided significant insight into the gene regulatory mechanisms associated with abiotic stress responses. These types of in silico approaches have facilitated the plant science community's future goals of developing multi-scale models of responses to iron deficiency stress and other abiotic stress conditions.
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PMID:Computational solutions for modeling and controlling plant response to abiotic stresses: a review with focus on iron deficiency. 3261 68