Stability of the pstS transcript of Escherichia coli.
The pst operon of Escherichia coli is composed of five genes that encode a high-affinity phosphate transport system. As a member of the PHO regulon, pst transcription is activated under phosphate shortage conditions. Under phosphate-replete conditions, the pst operon also functions as a negative regulator of the PHO genes. Transcription of pst is initiated at the promoter located upstream to the first gene, pstS. Immediately after its synthesis, the primary transcript of pst is cleaved into shorter mRNA molecules. The transcription unit corresponding to pstS is significantly more abundant than the transcripts of the other pst genes due to stabilisation of pstS mRNA by a repetitive extragenic palindrome (REP) structure downstream to the pstS locus. The presence of the REP sequence also results in an increased level of PstS proteins. However, the surplus level of PstS proteins produced in the presence of REP does not contribute to the repressive role of Pst in PHO expression.
Aguena
Meire
M
Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, CEP 05508-900, Brazil.
Ferreira
Gerson Moura
GM
Spira
Beny
B
D001483:Base Sequence; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon; D033902:Periplasmic Binding Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D028044:Phosphate-Binding Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; D033902:Periplasmic Binding Proteins; D028044:Phosphate-Binding Proteins; C090133:PstS protein, E coli; D012329:RNA, Bacterial