D. Robichon et al., Expression of a new operon from Bacillus subtilis, ykzB-ykoL, under the control of the TnrA and PhoP-PhoR global regulators, J BACT, 182(5), 2000, pp. 1226-1231
The ykzB and ykoL genes encode two peptides, of 51 and 60 amino acids, the
functions of which are unknown. The ykzB and tnrA genes are contiguous and
transcribed divergently. Expression of ykzB and ykoL is induced by glutamat
e and is under the control of the TnrA global regulator of nitrogen utiliza
tion. TnrA regulated its own synthesis in glutamate minimal medium. Two DNA
sequences (TnrAB1 and TnrAB2) homologous to the TnrA binding site are pres
ent in the region between tnrA and ykzB. Deletion mapping indicated that th
e TnrAB2 binding site was involved in activation of the ykzB promoter. In a
ddition, transcription of tnrA depends on the presence of the TnrAB1 bindin
g site. The ykzB and ykoL genes are probably in the same transcriptional un
it. A single promoter involved in transcription in the presence of glutamat
e was mapped by primer extension. ykoL expression was induced by phosphate
limitation and depended on the PhoP-PhoR two-component regulatory system. I
ts promoter was mapped to the region between ykoL, and ykzB. Four boxes sim
ilar to the PhoP binding site are present upstream from the ykoL promoter.
These boxes are probably recognized by PhoP similar to P during the activat
ion of transcription in phosphate limitation conditions.