Project description:In addition to its essential metabolic functions biotin is suggested a critical role in regulating gene expression. The first committed enzyme in biotin biosynthesis in Arabidopsis, 7-keto-8-aminopelargonic acid synthase is encoded by At5g04620 (BIO4). We isolated a novel T-DNA insertion mutant of BIO4 (bio4-1) showing a spontaneous cell death phenotype that could be rescued both by exogenous biotin and genetic complementation. The bio4-1 plants exhibited massive accumulation of hydrogen peroxide. The T-DNA insertion in the bio4-1 mutant contains a Methionine Sulfoxide Reductase B9 (AT4G21850) under a constitutive 35S CaMV promoter. To dissect the specific effects of biotin defiency on gene expression on a genome wide scale, we compared expression of wt Col-0 leaves with bio4-1 mutants and bio4-1 mutants complemented with D-biotin.
Project description:In addition to its essential metabolic functions biotin is suggested a critical role in regulating gene expression. The first committed enzyme in biotin biosynthesis in Arabidopsis, 7-keto-8-aminopelargonic acid synthase is encoded by At5g04620 (BIO4). We isolated a novel T-DNA insertion mutant of BIO4 (bio4-1) showing a spontaneous cell death phenotype that could be rescued both by exogenous biotin and genetic complementation. The bio4-1 plants exhibited massive accumulation of hydrogen peroxide. The T-DNA insertion in the bio4-1 mutant contains a Methionine Sulfoxide Reductase B9 (AT4G21850) under a constitutive 35S CaMV promoter. To dissect the specific effects of biotin defiency on gene expression on a genome wide scale, we compared expression of wt Col-0 leaves with bio4-1 mutants and bio4-1 mutants complemented with D-biotin. Expression in leaves of Col-0 wt, bio4-1 mutants with a T-DNA insertion in the 5`-UTR of BIO4, and bio4-1 mutants complemented with watering with 200µM D-biotin.
Project description:The budding yeast S. cerevisiae responds to depletion of iron in the environment by activating Aft1p, the major iron-dependent transcription factor, and by transcribing systems involved in the uptake of iron. Here we have studied the transcriptional response to iron deprivation, and have identified new Aft1p target genes. We find that other metabolic pathways are regulated by iron: biotin uptake and biosynthesis, nitrogen assimilation, and purine biosynthesis. Two enzymes active in these pathways, biotin synthase and glutamate synthase, require an iron-sulfur cluster for activity. Iron deprivation activates transcription of the biotin importer and simultaneously represses transcription of the entire biotin biosynthetic pathway. Multiple genes involved in nitrogen assimilation and amino acid metabolism are induced by iron deprivation, while glutamate synthase, a key enzyme in nitrogen assimilation, is repressed. A CGG palindrome within the promoter of glutamate synthase confers iron-regulated expression, suggesting control by a transcription factor of the binuclear zinc cluster family. We provide evidence that yeast subjected to iron deprivation undergo a transcriptional remodeling, resulting in a shift from iron-dependent to parallel, but iron-independent, metabolic pathways. A dose response design type examines the relationship between the size of the administered dose and the extent of the response of the organism(s). Keywords: dose_response_design
Project description:The budding yeast S. cerevisiae responds to depletion of iron in the environment by activating Aft1p, the major iron-dependent transcription factor, and by transcribing systems involved in the uptake of iron. Here we have studied the transcriptional response to iron deprivation, and have identified new Aft1p target genes. We find that other metabolic pathways are regulated by iron: biotin uptake and biosynthesis, nitrogen assimilation, and purine biosynthesis. Two enzymes active in these pathways, biotin synthase and glutamate synthase, require an iron-sulfur cluster for activity. Iron deprivation activates transcription of the biotin importer and simultaneously represses transcription of the entire biotin biosynthetic pathway. Multiple genes involved in nitrogen assimilation and amino acid metabolism are induced by iron deprivation, while glutamate synthase, a key enzyme in nitrogen assimilation, is repressed. A CGG palindrome within the promoter of glutamate synthase confers iron-regulated expression, suggesting control by a transcription factor of the binuclear zinc cluster family. We provide evidence that yeast subjected to iron deprivation undergo a transcriptional remodeling, resulting in a shift from iron-dependent to parallel, but iron-independent, metabolic pathways. A dose response design type examines the relationship between the size of the administered dose and the extent of the response of the organism(s). Using regression correlation
Project description:The purpose of the study is to assess a new treatment for patients with liver tumor metastases from colorectal cancer. The treatment has never been used in humans before. The treatment foresees the use of two compounds: AvdinOX and [177Lu]DOTA-biotin.
AvidinOX is a new compound, essentially a natural protein obtained from hen eggs, while [177Lu]DOTA-biotin is a new chemical compound resulting from the combination of the DOTA-biotin (also deriving from a natural vitamin which is biotin) with the 177Lutetium, an atom which emits radiation.
AvidinOX will be injected directly into the metastases in the liver and [177Lu]DOTA-biotin will be injected into the arm vein.
One specific property of AvidinOX is that it chemically links to the tumor tissues when it is injected while maintaining the capacity to take up [177Lu]DOTA-biotin. Once locally bound in tumor tissue, AvidinOX becomes an "artificial receptor" for intravenously injected [177Lu]DOTA-biotin, which allows an internal radiation therapy of the tumor tissue.
The treatment of liver metastases with local injection of AvidinOX and the following intra-venous injection of [177Lu]DOTA-biotin could be simpler and more tolerable than the current available treatments.