title: Translational repression of TEM beta-lactamase synthesis as a response of Escherichia coli to heat shock.
abstract: As a result of a temperature shift-up from 30 degrees C to 42 degrees C, beta-lactamase synthesis in Escherichia coli carrying pBR322 ceased transiently, even though the level of beta-lactamase mRNA was not altered. pBR328-directed pre-beta-lactamase synthesis in an in vitro transcription-translation coupled system was also repressed by incubation at the higher temperature. Translation of the lacZ sequence from the amp translation start signal, inserted into the open reading frame vector pORF1, was also repressed transiently upon the temperature shift-up. Pre-heating of the in vitro coupled system at 45 degrees C specifically reduced its capacity for pre-beta-lactamase synthesis. This capacity was restored by the addition of a 160,000 x g supernatant prepared from E. coli grown at 30 degrees C, but not by the supernatant from the cells incubated at 42 degrees C. These and other results indicate that (i) the 160,000 x g supernatant contains a heat-labile protein(s) that is required for efficient initiation of the translation of pre-beta-lactamase mRNA, and (ii) the heat shock-induced repression of beta-lactamase synthesis is due to inactivation of the protein(s) in the 160,000 x g supernatant.
authors.affiliation: Institute for Protein Research, Osaka University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kuriki
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D015152:Blotting, Northern; D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D005798:Genes, Bacterial; D006358:Hot Temperature; D007763:Lac Operon; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D012333:RNA, Messenger; D000667:Ampicillin; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1