4a). Furthermore, decreased expression of the trx gene in the ΔwhcE mutant was recovered to a level higher than that of the wild-type in the complemented strain (Fig. 4b). The phenotype of ΔwhcE cells carrying the P180-whcB clone was identical to that of the wild-type cells carrying the P180-whcE clone. These

data clearly indicate that the whcB gene, when overexpressed with loss of control during growth, can supplement the functional defect caused by the whcE mutation, suggesting structural similarity and http://www.selleckchem.com/ATM.html an evolutionary relationship between the two proteins. However, as the ΔwhcE mutation was not complemented by a chromosomal copy of the intact whcB gene, which was preferentially expressed in stationary phase, there is an implied role for whcE gene expression in exponential growth phase. In addition, as the ΔwhcB mutant did not show growth retardation, which was observed with the ΔwhcE mutant, it is reasonable to conclude that the native function of the selleck chemicals whcB gene is also different from that of the whcE gene. It is clear that although WhcB is structurally similar to WhcE, the whcB gene appears to play a novel role as a stationary-phase-specific regulatory gene by tightly controlling its expression during growth. Based on the above observations, we were able to conclude that the whcB gene plays a regulatory role during growth,

especially in stationary phase, by controlling the expression of a single gene or genes involved in the oxidative stress response pathway. As the next step, we attempted to identify additional genes under the control of whcB via 2D-PAGE analysis using cells in early stationary phase. As shown

in Fig. 5, we were able to identify protein spots showing increased density in the whcB-overexpressing strain, such as phosphoglucomutase (NCgl2453), cysteine synthase (NCgl2473) and sulfate adenyltransferase subunit 1 (NCgl2715), as well as spots showing decreased intensity, Fludarabine order such as NADH oxidase (NCgl0328), oxidoreductrase (NCgl1213), phosphoglycerate dehydrogenase (NCgl1235), iron-regulated ABC-type transporter (NCgl1502), polyphosphate glucokinase (NCgl1835) and manganese superoxide dismutase (NCgl2826) (Fig. 5a). Interestingly, proteins involved in electron transfer reactions were mainly affected in the whcB-overexpressing strain. We also analysed the expression profiles of the ORFs by monitoring transcription of the genes with quantitative RT-PCR. Consistent with the 2D-PAGE data, the mRNA levels of the ORFs agreed well with the protein data (Fig. 5b and c), suggesting a regulatory role for the whcB gene in stationary phase in the electron transfer reactions. This work was supported by grants from CJ Co. Ltd. (to H.-S.L.) and the Ministry of Education, Science and Technology (via 21C Frontier Microbial Genomics and Applications Center to H.-S.L.).