Regulation of ptsH and ptsI gene expression in Streptococcus salivarius ATCC 25975.
The transcriptional regulation of the Streptococcus salivarius ptsH and ptsI genes coding for the general energy-coupling proteins HPr and enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system were investigated. These genes form an operon with the gene order ptsH-ptsI. Three distinct mRNA species were detected: a 0.5 kb transcript specific for ptsH, and two long transcripts (2.2 and 2.4 kb) covering the whole pts operon. Transcription of all these mRNAs initiated at the same nucleotide located 9 bp downstream from a promoter located immediately upstream from the ptsH gene. The presence of a high-energy stem-loop structure (T0) located at the beginning of ptsI was responsible for the premature transcription termination generating the 0.5 kb ptsH-specific transcript. The long transcripts ended in the poly(U) region of two rho-independent-like terminators (T1 and T2) at the 3' end of ptsI. Studies with a 2-deoxyglucose-resistant spontaneous mutant of S. salivarius (L26) that produces an HPr-EI fusion protein suggest that the regulation of HPr and EI expression involves transcriptional as well as translational mechanisms.
Gagnon
G
G
Département de Biochimie (Sciences), Université Laval, Québec, Canada.
Vadeboncoeur
C
C
Gauthier
L
L
Frenette
M
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D017931:DNA Primers; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000096:biosynthesis / Q000235:genetics*; D017852:Phosphotransferases (Nitrogenous Group Acceptor) / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D013291:Streptococcus / Q000235:genetics* / Q000378:metabolism; D013728:Terminator Regions, Genetic / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
D001426:Bacterial Proteins; D017931:DNA Primers; D012333:RNA, Messenger; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D017852:Phosphotransferases (Nitrogenous Group Acceptor); C022360:phosphoenolpyruvate-protein phosphotransferase; D015719:Single-Strand Specific DNA and RNA Endonucleases