Eukaryotic Heme Utilization

真核血红素利用

• 批准号: 7593673
• 负责人: Caroline Philpott
• 金额: $ 25.12万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7593673
• 关键词: Binding; Biochemical Genetics; Biological; Caenorhabditis elegans; Cell membrane; Cells; Collaborations; Condition; Copper; Enzymes; Eukaryota; Eukaryotic Cell; Friedreich Ataxia; Genes; Genetic; Heme; Heme Iron; Hemoglobin; Hereditary Disease; Hereditary hemochromatosis; Homeostasis; Human; Hypoxia; Intracellular Transport; Iron; Iron Compounds; Iron Overload; Mammals; Maryland; Metabolism; Microarray Analysis; Myoglobin; Numbers; Nutrient; Organic Iron Compounds; Organism; Oxygen; Porphyrins; Process; Regulation; Role; Saccharomyces cerevisiae; Saccharomycetales; System; Toxin; Universities; Yeasts; Zinc; cofactor; deprivation; expression vector; heme a; human disease; insight; iron metabolism; metal metabolism; microorganism; protoporphyrin IX; response; uptake

Very little is known about heme transport in eukaryotes and a heme-specific transport uptake systems have not been identified in yeast. Although S. cerevisiae does not take up heme in response to iron deprivation, we have determined that this species does have an inducible heme uptake system that is activated under heme deficiency and hypoxic conditions. We performed microarray analysis of strains grown under these conditions, and found that a number of putative transporters are transcriptionally activated. We have identified transporters that, when over expressed, increase heme uptake into yeast. We have also identified a transporter, termed PUG1 (Porphyrin uptake gene 1), that stimulates the uptake of protoporphyrin IX, the immediate precursor of heme, and simultaneously inhibits the utilization of heme. This transporter is transcriptionally activated by oxygen and heme deficiency and is expressed on the plasma membrane of yeast. In collaboration with Iqbal Hamza of the University of Maryland, we are functionally characterizing the putative heme transporters of C. elegans by expressing them in yeast. Heme regulated genes from C. elegans will be cloned into yeast expression vectors and analyzed for heme uptake activity and their effects on intracellular pools of heme.

人们对真核生物中的血红素转运知之甚少，酵母中也没有鉴定出一种特定的血红素转运系统。尽管酿酒酵母不会对缺铁作出反应，但我们已经确定该物种确实有一个可诱导的血红素吸收系统，该系统在缺铁和低氧条件下被激活。我们对在这些条件下生长的菌株进行了微阵列分析，发现一些假定的转运蛋白在转录上被激活。我们已经确定了当过量表达时，增加酵母对血红素的吸收的转运蛋白。我们还发现了一种转运蛋白，称为PUG1(Porporrin Procept Gene 1)，它可以刺激血红素的直接前体原卟啉IX的摄取，同时抑制血红素的利用。这种转运蛋白在缺氧和血红素缺乏时被转录激活，并在酵母的质膜上表达。 与马里兰大学的Iqbal Hamza合作，我们正在通过在酵母中表达线虫可能的血红素转运蛋白来对它们进行功能表征。线虫的血红素调节基因将被克隆到酵母表达载体中，并分析其对血红素的吸收活性及其对细胞内血红素池的影响。