Carbon Source 의 변화에 의한 대장균의 pts Promoter 전사 조절 기작 = Mechanism of Regulation of the pts Promoter Transcription Initiation by Carbon Sources in Escherichia coli

다국어 초록 (Multilingual Abstract)

The pts operon, which encodes several factors in the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) of Escherichia coli, has multiple promoters which respond to different signals to facilitate quick adaptation to changes in growth conditions. The influence of an 1 kbp DNA region upstream of the pts PO promoter on pts expression was studied in vitro by employing the DNA templates containing both PO and PI promoter with or without the 1 kbp upstream DNA region for in vitro transcription assay. The 1 kbp DNA region upstream of the pts PO promoter, however, had no effect on pts transcription in vitro. The intracellular concentration of cAMP was measured when cells were grown in the presence of glucose, mannose, or mannitol. The transcription of PO was increased maximally in the presence of glucose even though the concentration of cAMP in the condition was lowest while the transcription from the PIb was highest when cells were grown in the presence of mannose or mannitol even though the intracellular concentration of cAMP was lower than cells grown in the absence of the sugar. These results suggest the possibility of the existence of a glucose inducible repressor specific for the PO promoter and a second repressor that is inducible by glucose, mannose and mannitol specific for the PI promoter (뒷장누락)