Identification of a cold shock transcriptional enhancer of the Escherichia coli gene encoding nucleoid protein H-NS.
The hns (27 min) gene encoding the 15.4-kDa nucleoid protein H-NS was shown to belong to the cold shock regulon of Escherichia coli, its expression being enhanced 3- to 4-fold during the growth lag that follows a shift from 37 degrees C to 10 degrees C. A 110-base-pair (bp) DNA fragment containing the promoter of hns fused to a promoterless cat gene (hns-cat fusion) conferred a similar cold shock response to the expression of chloramphenicol acetyltransferase (CAT) activity in vivo and in coupled transcription-translation systems prepared with extracts of cold-shocked cells. Extracts of the same cells produce a specific gel shift of the 110-bp DNA fragment and this fragment, immobilized on a solid support, specifically retains a single 7-kDa protein present only in cold-shocked cells that was found to be identical to F10.6 (CS7.4), the product of cspA. This purified protein, which is homologous to human DNA-binding protein YB-1, recognizes some feature of the 110-bp promoter region of hns and acts as a cold shock transcriptional activator of this gene since it stimulates the expression of CAT activity and of cat transcription in in vitro systems programmed with plasmid DNA carrying the hns-cat fusion.
La Teana
A
A
Department of Biology, University of Camerino, Italy.
Brandi
A
A
Falconi
M
M
Spurio
R
R
Pon
C L
CL
Gualerzi
C O
CO
D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D011994:Recombinant Proteins; C062260:cold shock protein CS7.4, Bacteria; D015500:Chloramphenicol O-Acetyltransferase