Conclusions

Given the vital role that the ribosome plays in the cell, it is check details unsurprising that it is an important target for antibiotic drugs [15]. Although current antibiotic strategies are directed at the functioning of the ribosome, it has been suggested that the ribosome assembly presents a target for novel drug discovery [16]. In support of this hypothesis, knockout of the non-essential ribosome biogenesis factors KsgA and GSK2118436 price YjeQ, a small-subunit associated GTPase, has been shown to affect bacterial virulence [6, 8, 17]. Therefore, a full understanding of these and other ribosome biogenesis factors in a variety of organisms is critical. We have extended the study of KsgA into S. aureus and found that KsgA is not as critical for bacterial growth and ribosome biogenesis as was previously shown to be the case in E. coli, although the ΔksgA knockout does have some negative effects. Additionally, overexpression of the catalytically inactive mutant did not have a dominant effect on growth or ribosome biogenesis in the presence of wild-type protein.

Although knockout and mutation of KsgA did not lead to severe growth defects, work in Y. pseudotuberculosis and E. amylovora suggests that small growth defects in vitro may correlate with larger effects BI-D1870 datasheet on virulence. Many researchers have suggested that targeting virulence may be a better strategy for antimicrobial therapy than targeting cell growth or viability [18, 19]. We

believe that further research on the role of KsgA in the virulence of S. aureus and other pathogens will prove instructive and may provide a viable drug development target. Methods Strains and plasmids The RN4220 strain, the pCN51 expression vector, and genomic DNA from S. aureus strain 8325 were gifts from Dr. Gordon Archer, Virginia Commonwealth University. The pMAD shuttle vector for knockout of ksgA was a gift from Dr. Gail Christie, Virginia Commonwealth University. We constructed a ksgA knockout Paclitaxel of the S. aureus RN4220 strain according to the method of Arnaud et al[20]. Allelic replacement was performed using the primers in Additional file 3; chromosomal knockout was confirmed by PCR. The ksgA gene was amplified from genomic DNA from S. aureus strain 8325, adding a ribosome binding sequence to ensure translation; primers used for cloning are shown in Additional file 3. The resulting fragment was subcloned into the pCN51 expression vector to produce pCN-WT. Mutagenesis was performed on this plasmid according to the Stratagene Quikchange protocol to produce pCN-E79A. The pCN51 constructs were transformed into strain RN4220 (RN) and the ksgA knockout strain (ΔksgA) by electroporation.