GalR Acts as a Transcriptional Activator of galKT in the Presence of Galactose in Streptococcus pneumoniae

We explored the regulatory mechanism of Leloir pathway genes in Streptococcus pneumoniae D39. Here, we demonstrate that the expression of galKT is galactose dependent. By microarray analysis and quantitative RT-PCR, we further show the role of the transcriptional regulator GalR, present upstream of galKT, as a transcriptional activator of galKT in the presence of galactose. Moreover, we predict a 19-bp regulatory site (5'-GATAGTTTAGTAAAATTTT-3' ) for the transcriptional regulator GalR in the promoter region of galK, which is also highly conserved in other streptococci. Growth comparison of Δ galK with the D39 wildtype strain grown in the presence of galactose shows that galK is required for the proper growth of S. pneumoniae on galactose. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series