Alternative promoters in the pst operon of Escherichia coli.
The pst operon of Escherichia coli is composed of five genes pstS, pstC, pstA, pstB and phoU, that encode a high-affinity phosphate transport system and a negative regulator of the PHO regulon. Transcription of pst is induced under phosphate shortage and is initiated at the promoter located upstream of the first gene of the operon, pstS. Here, we show by four different technical approaches the existence of additional internal promoters upstream of pstC, pstB and phoU. These promoters are not induced by Pi-limitation and do not possess PHO-box sequences. Plasmids carrying the pst internal genes partially complement chromosomal mutations in their corresponding genes, indicating that they are translated into functional proteins.
Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP 05508-900, Brazil. benys@usp.br
Beny
B
Spira
Meire
M
Aguena
Juliana Velasco
JV
de Castro Oliveira
Ezra
E
Yagil
D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D028061:Phosphate Transport Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D018085:Regulon; D020133:Reverse Transcriptase Polymerase Chain Reaction; D024363:Transcription Initiation Site
D017931:DNA Primers; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D028061:Phosphate Transport Proteins