Molecular characterization of Pseudomonas putida KT2440 rpoH gene regulation.
The rpoH gene of Pseudomonas putida KT2440 encoding the heat-shock sigma factor sigma(32) was cloned and sequenced, and the translated gene product was predicted to be a protein of 32.5 kDa. The unambiguous role of the gene as a sigma factor was confirmed because the cloned P. putida gene complemented the growth defect, at 37 and 42 degrees C, of an Escherichia coli rpoH mutant strain. Primer extension analysis showed that in P. putida the rpoH gene is expressed from three promoters in cells growing at 30 degrees C. Two of them, P1 and P3, share homology with the sigma(70)-dependent promoters, while the third one, P2, shows a typical sigma(24)-consensus sequence. The pattern of transcription initiation of the rpoH gene did not change in response to different stresses, i.e. a sudden heat shock or the addition of aromatic compounds. However, the predicted secondary structure of the 5' region of the mRNA derived from the three different promoters suggests regulation at the level of translation efficiency and/or mRNA half-life. An inverted repeat sequence located 20 bp downstream of the rpoH stop codon was shown to function as a terminator in vivo in P. putida growing at temperatures from 18 to 42 degrees C.
Manzanera
Maximino
M
Estación Experimental del Zaidı́n, CSIC, Departamento de Bioquı́mica y Biologı́a Molecular y Celular de Plantas, Apartado 419, E-18080 Granada, Spain1.
Aranda-Olmedo
Isabel
I
Estación Experimental del Zaidı́n, CSIC, Departamento de Bioquı́mica y Biologı́a Molecular y Celular de Plantas, Apartado 419, E-18080 Granada, Spain1.
Ramos
Juan L
JL
Estación Experimental del Zaidı́n, CSIC, Departamento de Bioquı́mica y Biologı́a Molecular y Celular de Plantas, Apartado 419, E-18080 Granada, Spain1.
Marqués
Silvia
S
Estación Experimental del Zaidı́n, CSIC, Departamento de Bioquı́mica y Biologı́a Molecular y Celular de Plantas, Apartado 419, E-18080 Granada, Spain1.
D001483:Base Sequence; D016384:Consensus Sequence; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D012808:Sigma Factor; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D006360:Heat-Shock Proteins; D006841:Hydrocarbons, Aromatic; D012333:RNA, Messenger; D012808:Sigma Factor; D014157:Transcription Factors; C069774:heat-shock sigma factor 32