Nutritional Control of Transcription Factor Expression

Summary

Principal Investigator: Michael Kilberg
Affiliation: University of Florida
Country: USA
Abstract: Mammalian cells respond to nutritional limitation of protein/amino acids by increasing the expression of a wide spectrum of proteins via a signaling pathway that will be referred to as the Amino Acid Response (AAR). Although it is known that amino acid availability can modulate protein expression, the mechanisms by which these events occur are not well understood. Using human HepG2 hepatoma cells, we have documented previously that amino acid limitation increases the expression of the bZIP transcription factor C/EBPb through transcriptional control and that, in turn, an elevated level of C/EBPb induces transcription from amino acid responsive genes. Initial studies for this application have yielded the novel observation that there is amino acid response element (AARE) activity in a 93 bp fragment from the human C/EBPb gene 3' to the protein coding sequence. Preliminary experiments have also shown that amino acid limitation causes an increase in the total abundance of C/EBPb protein and an increase in the nuclear translocation of C/EBPb phosphorylated on Thr235. Our global hypothesis is that transcriptional control of human C/EBPb expression and post-translational control of C/EBPb function represent important regulatory steps in the AAR pathway. Using protein restricted diets in rats and amino acid limitation of HepG2 cells the Specific Aims of the proposed studies are to: 1) identify the genomic AARE responsible for amino acid-dependent transcription of the C/EBPb gene by using deletion analysis, in vivo footprinting, and single nucleotide mutagenesis; 2) identify the AARE binding proteins and characterize their role in the AAR pathway; 3) determine if there are changes in synthesis or turnover of one of the three C/EBPb protein isoforms (LAP*, LAP, LIP); and 4) investigate whether or not phosphorylation of C/EBPb is important in regulating the role that it plays in signaling amino acid availability. Our long-term goal is to understand how mammalian cells respond to their nutritional environment through gene expression, using amino acid availability as the model.
Funding Period: 2006-03-01 - 2011-02-28
more information: NIH RePORT

Top Publications

  1. pmc Alignment of the transcription start site coincides with increased transcriptional activity from the human asparagine synthetase gene following amino acid deprivation of HepG2 cells
    Hong Chen
    Department of Biochemistry and Molecular Biology, Center for Mammalian Genetics, and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, FL 32610 0245, USA
    J Nutr 136:2463-7. 2006
  2. pmc Specificity of amino acid regulated gene expression: analysis of genes subjected to either complete or single amino acid deprivation
    S S Palii
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida, College of Medicine, Box 100245, Gainesville, FL 32610 0245, USA
    Amino Acids 37:79-88. 2009
  3. pmc C/EBP homology protein (CHOP) interacts with activating transcription factor 4 (ATF4) and negatively regulates the stress-dependent induction of the asparagine synthetase gene
    Nan Su
    Department of Biochemistry and Molecular Biology, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    J Biol Chem 283:35106-17. 2008
  4. pmc Activated transcription via mammalian amino acid response elements does not require enhanced recruitment of the Mediator complex
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA
    Nucleic Acids Res 36:5571-80. 2008
  5. doi Mass spectrometric quantification of asparagine synthetase in circulating leukemia cells from acute lymphoblastic leukemia patients
    Susan E Abbatiello
    Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
    J Proteomics 71:61-70. 2008
  6. pmc MEK signaling is required for phosphorylation of eIF2alpha following amino acid limitation of HepG2 human hepatoma cells
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    J Biol Chem 283:10848-57. 2008
  7. pmc Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation
    Kimberly J Aiken
    Department of Neuroscience, McKnight Brain Institute, Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, USA
    J Biol Chem 283:10252-63. 2008
  8. pmc Deprivation of protein or amino acid induces C/EBPbeta synthesis and binding to amino acid response elements, but its action is not an absolute requirement for enhanced transcription
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Center for Nutritional Sciences, and Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA
    Biochem J 410:473-84. 2008
  9. pmc Activation of the ATF3 gene through a co-ordinated amino acid-sensing response programme that controls transcriptional regulation of responsive genes following amino acid limitation
    Yuan Xiang Pan
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    Biochem J 401:299-307. 2007
  10. pmc Protein or amino acid deprivation differentially regulates the hepatic forkhead box protein A (FOXA) genes through an activating transcription factor-4-independent pathway
    Nan Su
    Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610 0245, USA
    Hepatology 50:282-90. 2009

Detail Information

Publications10

  1. pmc Alignment of the transcription start site coincides with increased transcriptional activity from the human asparagine synthetase gene following amino acid deprivation of HepG2 cells
    Hong Chen
    Department of Biochemistry and Molecular Biology, Center for Mammalian Genetics, and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, FL 32610 0245, USA
    J Nutr 136:2463-7. 2006
    ..To our knowledge, these results are the first example in a mammalian cell of transcription start selection by nutrient availability...
  2. pmc Specificity of amino acid regulated gene expression: analysis of genes subjected to either complete or single amino acid deprivation
    S S Palii
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida, College of Medicine, Box 100245, Gainesville, FL 32610 0245, USA
    Amino Acids 37:79-88. 2009
    ..Furthermore, caution must be exercised when using a medium completely devoid of amino acids...
  3. pmc C/EBP homology protein (CHOP) interacts with activating transcription factor 4 (ATF4) and negatively regulates the stress-dependent induction of the asparagine synthetase gene
    Nan Su
    Department of Biochemistry and Molecular Biology, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    J Biol Chem 283:35106-17. 2008
    ..Collectively, the results document that CHOP is a member of the transcription factor network that controls the stress-induced regulation of specific C/EBP-ATF-containing genes, such as ASNS...
  4. pmc Activated transcription via mammalian amino acid response elements does not require enhanced recruitment of the Mediator complex
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA
    Nucleic Acids Res 36:5571-80. 2008
    ..These results document that activation of the SNAT2 gene by the mammalian amino acid response pathway occurs independently of enhanced Mediator recruitment...
  5. doi Mass spectrometric quantification of asparagine synthetase in circulating leukemia cells from acute lymphoblastic leukemia patients
    Susan E Abbatiello
    Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
    J Proteomics 71:61-70. 2008
    ....
  6. pmc MEK signaling is required for phosphorylation of eIF2alpha following amino acid limitation of HepG2 human hepatoma cells
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    J Biol Chem 283:10848-57. 2008
    ..Collectively, these results document a critical interdependence between the MEK-ERK MAPK signaling pathway and the amino acid stress-activated pathway...
  7. pmc Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation
    Kimberly J Aiken
    Department of Neuroscience, McKnight Brain Institute, Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, USA
    J Biol Chem 283:10252-63. 2008
    ....
  8. pmc Deprivation of protein or amino acid induces C/EBPbeta synthesis and binding to amino acid response elements, but its action is not an absolute requirement for enhanced transcription
    Michelle M Thiaville
    Department of Biochemistry and Molecular Biology, Center for Nutritional Sciences, and Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA
    Biochem J 410:473-84. 2008
    ....
  9. pmc Activation of the ATF3 gene through a co-ordinated amino acid-sensing response programme that controls transcriptional regulation of responsive genes following amino acid limitation
    Yuan Xiang Pan
    Department of Biochemistry and Molecular Biology, Genetics Institute, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, Florida 32610, USA
    Biochem J 401:299-307. 2007
    ....
  10. pmc Protein or amino acid deprivation differentially regulates the hepatic forkhead box protein A (FOXA) genes through an activating transcription factor-4-independent pathway
    Nan Su
    Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610 0245, USA
    Hepatology 50:282-90. 2009
    ..Collectively, the results document that the hepatic FOXA family of genes are differentially regulated by amino acid availability...