A5103139847- Lipid metabolism and biosynthesis
- Fungal and yeast genetics research
- Endoplasmic Reticulum Stress and Disease
- Microbial Metabolic Engineering and Bioproduction
- Phytase and its Applications
- Biofuel production and bioconversion
- Enzyme Production and Characterization
- Cellular transport and secretion
- Plant nutrient uptake and metabolism
- Mitochondrial Function and Pathology
- Legume Nitrogen Fixing Symbiosis
- Photosynthetic Processes and Mechanisms
- RNA and protein synthesis mechanisms
- Enzyme Catalysis and Immobilization
- RNA Research and Splicing
- Fermentation and Sensory Analysis
- Lipid Membrane Structure and Behavior
- Adipose Tissue and Metabolism
- Pineapple and bromelain studies
- Microbial Metabolites in Food Biotechnology
- Plant Reproductive Biology
- Cassava research and cyanide
- Plant biochemistry and biosynthesis
- Bacterial Genetics and Biotechnology
- Cancer Genomics and Diagnostics
Scholar Rock (United States)
2023-2024
Cornell University
2009-2022
Genetic Improvement and Adaptation of Mediterranean and Tropical Plants
2017
Centre de Coopération Internationale en Recherche Agronomique pour le Développement
2017
Pediatrics and Genetics
2015
Rutgers, The State University of New Jersey
1983-2007
Babraham Institute
2004
Carnegie Mellon University
1993-2002
Graz University of Technology
1988-1994
Loyola University Chicago
1993
Cells regulate the biophysical properties of their membranes by coordinated synthesis different classes lipids. Here, we identified a highly dynamic feedback mechanism which budding yeast Saccharomyces cerevisiae can phospholipid biosynthesis. Phosphatidic acid on endoplasmic reticulum directly bound to soluble transcriptional repressor Opi1p maintain it as inactive outside nucleus. After addition lipid precursor inositol, this phosphatidic was rapidly consumed, releasing from and allowing...
ABSTRACT Fifty-two inositol-requiring mutants of Saccharomyces cerevisiae were isolated following mutagenesis with ethyl methanesulfonate. Complementation and tetrad analysis revealed ten major complementation classes, representing independently segregating loci (designated in01 through inol0) which recombined freely their respective centromeres. Members any given class segregated as alleles a single locus. Thirteen subclasses identified among thirty-six behaved the inol The map for these...
A purification procedure for L-myo-inositol-1-phosphate synthase (EC 5.5.1.4) from yeast is described. The method routinely produces enrichments of 500-fold with 20-40% yields. In addition, a obtaining highly specific and purified antibody against the protein molecular weight native enzyme as determined by gel filtration approximately 240,000. single subunit Mr = 62,000 detected upon sodium dodecyl sulfate-gel electrophoresis enzyme. was used to assay crude extracts wild type...
The IN04 gene encodes a protein required for derepression of number structural genes encoding enzymes involved in phospholipid biosynthesis the yeast Saccharomyces cerevisiae.Ino4p shows similarity to basic helix-loop-helix (bHLH) family regulatory proteins (Hoshizaki, D. K., Hill, J. E., and Henry, S. A. (1990)
Three mutants of the yeast Saccharomyces cerevisiae which require exogenous ethanolamine or choline were isolated. The map to a single locus (cho1) on chromosome V. lipid composition suggests that cho1 do not synthesize phosphatidylserine under any growth conditions. If phosphatidylethanolamine phosphatidylcholine, are usually derived from phosphatidylserine, synthesized choline, grew and divided relatively normally. However, mitochondrial abnormalities evident even when supplied. Diploids...
Five allelic Saccharomyces cerevisiae mutants deficient in the methylation of phosphatidylethanolamine (PE) have been isolated, using two different screening techniques. Biochemical analysis suggested that these define a locus, designated CHO2, may encode methyltransferase. Membranes cho2 mutant cells grown defined medium contain approximately 10% phosphatidylcholine (PC) and 40-50% PE as compared to wild-type levels 40-45% PC 15-20% PE. In spite this greatly altered phospholipid...
Genome-scale metabolic models are built using information from an organism's annotated genome and, correspondingly, on reactions catalyzed by the set of enzymes encoded genome. These have been successfully applied to guide engineering increase production metabolites industrial interest. Congruity between simulated and experimental behavior is influenced accuracy representation network in model. In interest applying consensus model Saccharomyces cerevisiae metabolism for increased...
Abstract We report the isolation of two new opi3 mutants by EMS mutagenesis, and construction an insertion allele in vitro using cloned gene. have demonstrated that mutations cause a deficiency terminal phospholipid N-methyltransferase (PLMT) activities required for de novo synthesis PC (phosphatidylcholine). The mutants, under certain growth conditions, produce membrane virtually devoid although, surprisingly, none displays strict auxotrophic requirement choline. Although grow without...
The structural gene (CHO1) for phosphatidylserine synthase (CDPdiacylglycerol:L-serine O-phosphatidyltransferase, EC 2.7.8.8) was isolated by genetic complementation in Saccharomyces cerevisiae from a bank of yeast genomic DNA on chimeric plasmid. cloned (4.0 kilobases long) shown to represent unique sequence the genome. an integrative plasmid recombine into CHO1 locus, confirming its identity. cho1 strain transformed with this autonomously replicating had significantly increased activity...
ABSTRACT The enzyme inositol-1-phosphate synthase (I-1-P synthase), product of the INO1 locus, catalyzes synthesis from substrate glucose-6-phosphate. activity this is dramatically repressed in presence inositol. By selecting for mutants which overproduce and excrete inositol, we have identified constitutive as well a mutation phospholipid biosynthesis. Genetic analysis indicates that at least three loci (designated OPI1, OPI2 OPI4) direct inositol-mediated repression I-1-P synthase. Mutants...
Upon starvation for inositol, a phospholipid precursor, an inositol-requiring mutant of Saccharomyces cerevisiae has been shown to die if all other conditions are growth supporting. The and metabolism inositol-starved cells investigated in order determine the physiological state leading "inositolless death". synthesis major inositol-containing ceases within 30 min after removal inositol from medium. cells, however, continue apparently normal fashion one generation (2 h under used this...
Maintenance of energy homeostasis depends on the highly regulated storage and release triacylglycerol primarily in adipose tissue, excessive is a feature common metabolic disorders. CIDEA lipid droplet (LD)-protein enriched brown adipocytes promoting enlargement LDs, which are dynamic, ubiquitous organelles specialized for storing neutral lipids. We demonstrate an essential role this process amphipathic helix CIDEA, facilitates embedding LD phospholipid monolayer binds phosphatidic acid...
The addition of inositol to the growth medium Saccharomyces cerevisiae resulted in rapid changes rates phospholipid biosynthesis. partitioning intermediate CDP-diacylglycerol was shifted phosphatidylinositol at expense phosphatidylserine and its derivatives phosphatidylethanolamine phosphatidylcholine. Serine 133-fold greater concentrations than that but a much lesser degree. Kinetic experiments with pure synthase indicated between not governed by affinities both enzymes have for their...
The <i>SEC14</i> gene encodes a phosphatidylinositol/phosphatidylcholine transfer protein essential for secretion and growth in yeast (1). Mutations (<i>cki1, cct1</i>, <i>cpt1</i>) the CDP-choline pathway phosphatidylcholine synthesis suppress <i>sec14</i> defect (2), permitting <i>sec14</i><sup>ts</sup> <i>cki1, sec14</i><sup>ts</sup> <i>cct1</i>, and<i>sec14</i><sup>ts</sup> <i>cpt1</i> strains to grow at the<i>sec14</i><sup>ts</sup> restrictive temperature. Previously, we reported that...
In the yeast Saccharomyces cerevisiae, transcription of many genes encoding enzymes phospholipid biosynthesis are repressed in cells grown presence precursors inositol and choline. A genome-wide approach using cDNA microarray technology was used to profile changes expression all that respond exogenous We report global response is completely distinct from effect Whereas on gene primarily repressing, choline activating. Moreover, combination increased number compared with alone enhanced...
To study the consequences of depleting major membrane phospholipid phosphatidylcholine (PC), exponentially growing cells a yeast cho2opi3 double deletion mutant were transferred from medium containing choline to choline-free medium. Cell growth did not cease until PC level had dropped below 2% total phospholipids after four five generations. Increasing contents phosphatidylethanolamine (PE) and phosphatidylinositol made up for loss PC. During depletion, remaining was subject acyl chain...
The INO1 gene of Saccharomyces cerevisiae encodes the regulated enzyme inositol-1-phosphate synthase, which catalyzes first committed step in synthesis inositol-containing phospholipids. expression this was analyzed under conditions known to regulate phospholipid synthesis. RNA blot hybridization with a genomic clone for detected two species 1.8 and 0.6 kb. abundance 1.8-kb greatly decreased when cells were grown presence precursor inositol, as activity synthase. Complementation analysis...
The promoter region of the highly regulated INO1 structural gene yeast has been investigated. major transcription initiation start site (+1) was mapped to a position located five nucleotides upstream previously identified codon. TATA is at −116 −111. used construct fusions Escherichia coli IacZ gene. All fusion constructs that retained regulation in response phospholipid precursors inositol and choline, contained least one copy nine bp repeated element (consensus, 5′-ATGTGAAAT-3′). smallest...
Inositol biosynthesis was studied in soluble, cell extracts of a wild-type (Ino) strain Saccharomyces cerevisiae. Two reactions were detected: (i) conversion D-glucose-6-phosphate to phosphorylated form inositol, presumably inositol-1-phosphate (IP synthethase, EC5.5.1.4), and (ii) inositol phosphatase, EC3.1.3.25). The vitro rate glucose-6-phosphate proportional incubaion time enzyme concentration. pH optimum 7.0. synthesis required oxidized nicotinamide adenine dinucleotide (NAD)...