Project description:Microorganisms can restructure their transcriptional output to adapt to environmental conditions by sensing endogenous metabolite pool. In this study, an Agilent customized microarray representing approximately 4,106 genes was used to study temporal transcript profiles of Bacillus subtilis in response to valine, glutamate and glutamine pulses. Amino-acid-regulated genes were identified having significantly changed expression at one or more time points in response to pulses of valine, glutamate, and glutamine, respectively, and Val-, Glu and Gln-specific genes were further distinguished from them. Different amino acid treatments were compared in terms of both the global temporal profiles and the 5-minute quick regulations, and between-experiment differential genes were identified. The highlighted genes were analyzed based on diverse sources of gene functions using a variety of computational tools, including T-profiler analysis, hierarchical clustering and enrichment of functional categories. The results revealed the common and distinct modes of action of these three amino acids, and should help to elucidate the specific signaling mechanism of each amino acid as an effector. Three amino acids (Glutamate, Glutamine, and Valine) were adopted to perturb the culture of subtilis. Four time-points were investigated for each perturbation. There are two replicates for the first time-point of Valine-treatment experiment.
Project description:Correct charging of tRNAs with their corresponding amino acid is crucial for accurate translation of the genetic code into proteins. However, a growing body of evidence shows that unicellular organisms (bacteria and yeast) can sacrifice translational fidelity to preserve protein synthesis under deprivation of specific essential amino acids.1 Several weeks ago, Pataskar and colleagues described the first instance of codon reassignments caused by amino acid restriction in mammalian cells. Specifically, when human cancer cells were deprived of tryptophan (W), tRNATrp was misacylated with the structurally similar amino acid phenylalanine (F) by tryptophanyl-tRNA synthetase (WARS1), resulting in W>F substitutions in synthesized proteins.2 The authors show that W>F substitutions do preserve translation, but generally result in dysfunctional proteins and that presentation of W>F peptides stimulates T cell-mediated killing. Together this would impair survival of cancer cells that incorporate W>F substitutions in their proteome.2 In the context of growing interest in amino acid depletion diets and related disorders,2 we wondered whether amino acid substitutions are restricted to pathological states like cancer or may represent a more generalized mechanism to maintain translation despite unfavorable circumstances. It is known that ARSs can misactivate tRNAs with structurally similar amino acids3, but editing activity ensures extreme specificity under physiological conditions.4,5 Given the structural similarities between isoleucine and valine, we speculated that isoleucyl-tRNA synthetase (IARS1) would misacylate tRNAIle with valine under isoleucine restriction, leading to I>V substitutions in the proteome. Not only did these substitutions occur in healthy primary human cells, but they also preserved translation and promoted cell viability upon nutritional stress.
Project description:In this study, we explored the use of BONCAT in Synechococcus sp. – a globally important cyanobacteria. We characterized the growth and microscopically quantified HPG uptake under a range of HPG concentrations in marine Synechococcus sp. Further, we examined changes in protein expression of Synechococcus sp. grown under normal and nitrate-stressed conditions relative to a non-HPG control.
Project description:Samples-WT Basal condition primary cortex cells; WT B27 Starved-Primary cortex cells starved overnight without B27 supplement media. WT AA Starved-Primary cortex cell starved without amino acid for 2 hours. WT AA Refed-Primary cortex cell refed for 1 hour after amino acid starvation. KO Basal-SLC38 Knockout Primary cortex cells starved overnight without B27 supplement media. KO B27 Starved-SLC38 Knockout Primary cortex cell starved without amino acid for 2 hours. KO AA starved-SLC38 Knockout Primary cortex cell refed for 1 hour after amino acid starvation. KO AA Refed-SLC38 Knockout Primary cortex cell refed for 1 hour after amino acid starvation.
Project description:In order to determine whether dis-regulation of a genetic pathway could explain the increased apoptosis of parp-2-/- double positive thymocytes, the gene expression profiles in double positive thymocytes derived from wild-type and parp-2-/- mice were analysed using Affymetrix oligonucleotide chips (mouse genome 430 2.0).