title: Control of RNA synthesis in Escherichia coli after a shift to higher temperature.
abstract: Parameters of RNA synthesis were measured after a temperature upshift in a pair of Escherichia coli B/r strains that are isogenic except for having relA and relA+ loci, to examine the cause for a reported anomaly in the correlation between guanosine tetraphosphate (ppGpp) and stable RNA (rRNA, tRNA) synthesis under such conditions. Two main results were: (i) the specific stable RNA gene activity (stable RNA per total RNA synthesis) correlated in the conventionally expected fashion with the level of ppGpp but was obscured by a nonspecific increase in the RNA chain elongation rate due to the higher temperature; (ii) the temperature upshift caused a transient reduction in the RNA polymerase activity (transcribing per total enzyme) that accounts for the previously observed oscillating RNA synthesis rate after a temperature shift.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D007700:Kinetics; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D012343:RNA, Transfer / Q000096:biosynthesis*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D006159:Guanosine Tetraphosphate; D012343:RNA, Transfer; D012321:DNA-Directed RNA Polymerases