H. Kinoshita et al., BUTYROLACTONE AUTOREGULATOR RECEPTOR PROTEIN (BARA) AS A TRANSCRIPTIONAL REGULATOR IN STREPTOMYCES-VIRGINIAE, Journal of bacteriology, 179(22), 1997, pp. 6986-6993
BarA of Streptomyces virginiae is a specific receptor protein for virg
iniae butanolides (VBs), a member of the butyrolactone autoregulators
of Streptomyces species. Sequencing around the barA gene revealed two
novel open reading frames: one upstream, barX, encoding a homolog of A
fsA of Streptomyces griseus and another downstream, barB. Northern (RN
A) blot analysis for S. virginiae demonstrated that the addition of VB
during cultivation switched on the expression of barB. An in vivo exp
ression system in Streptomyces lividans with the use of the xylE repor
ter gene indicated that BarA in conjunction with VB controlled the bar
B promoter, Furthermore, the DNA binding ability of BarA was demonstra
ted in vitro for the first time by means of surface plasmon resonance
and a gel-shift assay. Complex formation with VB in vitro resulted in
the dissociation of BarA from DNA, thus suggesting that the VB recepto
r, BarA, is a transcriptional regulator and that the VB signal is tran
sduced to the next step in the signal transduction pathway by modifica
tion of the DNA binding ability of BarA.