Genomic sequences necessary for transcriptional activation by amino acid deprivation of mammalian cells.

The human genes for C/EBP homology protein (chop) and asparagine synthetase (AS) are model systems to investigate transcription induced by nutrient limitation and endoplasmic reticulum (ER) stress. The genomic cis-elements in the promoters of these two genes that mediate these responses have been identified and partially characterized. Multiple cis-elements are functional in each gene, but differences exist in the molecular mechanisms by which these genes respond to amino acid or glucose deprivation. Whereas chop expression is associated with cell stress and apoptosis, activation of the AS gene by ER stress indicates that asparagine may also be critical for cellular processes other than protein synthesis.