Alarmone

An alarmone is an intracellular signal molecule that is produced in bacteria, chloroplasts, and a slim minority of archaea reacting to hash environmental factors.[1] They regulate the gene expression at transcription level. Alarmones are produced in high concentrations when harsh environmental factors occur in bacteria and plants, such as lack of amino acids, to produce proteins. Stringent factors take uncharged tRNA and convert it to an alarmone. Guanosine-5'-triphosphate (GTP) is then converted to 5´-diphosphate 3´-diphosphate guanosine (ppGpp), the archetypical alarmone. ppGpp will bind to RNA polymerase β and β´ subunits, changing promoter preference. It will decrease transcription of rRNA and other genes but will increase transcription of genes involved in amino acid biosyntheses and metabolisms involved in famine.[2]

Notes
  1. Rinke C, Schwientek P, Sczyrba A, Ivanova NN, Anderson IJ, Cheng JF, Darling A, Malfatti S, Swan BK, Gies EA, Dodsworth JA, Hedlund BP, Tsiamis G, Sievert SM, Liu WT, Eisen JA, Hallam SJ, Kyrpides NC, Stepanauskas R, Rubin EM, Hugenholtz P, Woyke T (July 2013). "Insights into the phylogeny and coding potential of microbial dark matter" (PDF). Nature. 499 (7459): 431–437. doi:10.1038/nature12352. PMID 23851394.
  2. Jishage M, Kvint K, Shingler V, Nyström T (2002). "Regulation of ς factor competition by the alarmone ppGpp". Genes & Development. 16 (10): 1260–70. doi:10.1101/gad.227902. PMC 186289. PMID 12023304.
gollark: Really? What's your theory?
gollark: 0 or 0, I mean.
gollark: Maybe it means a zero-based binary numeral system, where all the digits are 0.
gollark: Well, it allows you to represent the absence of things, or to efficiently encode numbers using a place-value system.
gollark: It's zero, the number.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.