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mRNA Degradation vs Translation. Proteome-wide alterations in Escherichia coli translation rates upon anaerobiosis. 2010. C ombined fractional diagonal chromatography
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Proteome-wide alterations in Escherichia coli translation rates upon anaerobiosis 2010
Combined fractional diagonal chromatography • COFRADIC enriched azidohomoalanine (azhal) containing peptides using tris-(2-carboxy-ethyl)-phosphine (TCEP) to selectively modify peptides • Developed a pulse labeling method using the methionine analogue azhal • Tested after 10 minutes of anaerobiosis
Immediate and strong increase in synthesis rate of proteins involved in anaerobic respiration and fermentation. • The synthesis rates of glycolytic enzymes and PTS proteins increased as well, suggesting that the increased flux through glycolysis is not exclusively the result of metabolic regulation, but also regulated at the protein level. • Most of the proteins found to be down-regulated in synthesis were ribosomal proteins. • It has been well documented that under conditions of energy deficiency synthesis of rRNA is decreased leading to translational feedback inhibition of ribosomal proteins synthesis • These changes are induced by small regulatory RNAs that affect translation
Changes in the proteome can occur independently of mRNA degradation
Poly(A)-polymerase I links transcription with mRNA degradation via σSproteolysis 2006
Figure 6. PAPI-mediated effect on σS proteolysis. A. • σSis expressed under stressful conditions (stationary phase). PAPI reduces σSproteolysis under stressful conditions as shown by the decreased σS in the mutant without PAPI (two columns on the right of each graph and the right side of the blot)
Figure 8. Interplay among transcription, degradation and proteolysis machineries in the control of BolA and σSBolA levels in the cell • PAPI reduces proteolysis of σScaused by RssB and ClpX and reduces mRNA degradation caused by various enzymes. The increased σS levels induce the transcription and translation of various other proteins
mRNA degradation, proteolysis, and transcription work in concert to control subsequent gene expression and protein generation
Papers • http://www.ncbi.nlm.nih.gov/pubmed/20713451 • http://www.ncbi.nlm.nih.gov/pubmed/16556229