Control of mammalian gene expression by amino acids, especially glutamine

Abstract

A growing number of reports clearly demonstrate that amino acids are able to control physiological functions at different levels, including the initiation of protein translation, mRNA stabilization and gene transcription [1][2][3]. Although the molecular mechanisms involved in the control of gene expression by amino Molecular data rapidly accumulating on the regulation of gene expression by amino acids in mammalian cells highlight the large variety of mechanisms that are involved. Transcription factors, such as the basic-leucine zipper factors, activating transcription factors and CCAAT/enhancer-binding protein, as well as specific regulatory sequences, such as amino acid response element and nutrient-sensing response element, have been shown to mediate the inhibitory effect of some amino acids. Moreover, amino acids exert a wide range of effects via the activation of different signalling pathways and various transcription factors, and a number of cis elements distinct from amino acid response element/nutrient-sensing response element sequences were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine, the most abundant amino acid, which at appropriate concentrations enhances a great number of cell functions via the activation of various transcription factors. The glutamine-responsive genes and the transcription factors involved correspond tightly to the specific effects of the amino acid in the inflammatory response, cell proliferation, differentiation and survival, and metabolic functions. Indeed, in addition to the major role played by nuclear factor-jB in the anti-inflammatory action of glutamine, the stimulatory role of activating protein-1 and the inhibitory role of C/EBP homology binding protein in growth-promotion, and the role of c-myc in cell survival, many other transcription factors are also involved in the action of glutamine to regulate apoptosis and intermediary metabolism in different cell types and tissues. The signalling pathways leading to the activation of transcription factors suggest that several kinases are involved, particularly mitogen-activated protein kinases. In most cases, however, the precise pathways from the entrance of the amino acid into the cell to the activation of gene transcription remain elusive.

Effect of high-concentrate diet on amino acid transporter expression and milk quality in Holstein dairy cows

“…According to Table 5, glycogenic amino acid decreased, indicating that the cows do not have enough AA to use in the milk protein synthesis in the HC group. This is consistent with the findings of a previous study (Brasse-Lagnel et al, 2009).…”

Comprehensive Proteomic and Metabolomic Signatures of Nontypeable Haemophilus influenzae-Induced Acute Otitis Media Reveal Bacterial Aerobic Respiration in an Immunosuppressed Environment

“…Of these, a role for lysine during bacterial pathogenesis is unknown. Glutamine attenuates local inflammation through the NF-B pathway (114), but has no known role in AOM (114). Ornithine is the FIG.…”

Effect of a high-concentrate diet on milk components and mammary health in Holstein dairy cows

“…The first three squirts of milk were discarded, then approximately 5 mL milk was placed into a sterile tube and used to determine the milk fat and protein concentrations by Integrated Milk Testing TM Milkoscan 4000 (Foss Electric, Hillerod, Denmark). Additionally, the SCC of milk was determined using an electronic cell counter (Fossomatic, Foss Electric, Hillerod, Denmark) (Booth et al, 1995). Milk NAGase activity was determined using a kit (Jiancheng, Nanjing) according to the manufacturer instructions.…”