Peter Lewis

Biography

"My research career has focused on the gram positive bacterium Bacillus subtilis. During my PhD I purified and characterised the replication terminator protein (RTP) and its DNA binding sites (Lewis et al., J. Bacteriol 171, 3564-3567 (1989); Lewis et al., J. Mol. Biol. 214, 73-84 (1990)). These sites are regions of DNA where oppositely moving replication forks meet and newly replicated chromosomes are resolved prior to segregation. During my post-doctoral research I was responsible for the development of cell biological techniques and vectors for visualising gene expression and protein localisation in live bacterial cells (Lewis et al., PNAS 91, 3849-3853 (1994); Lewis et al., Mol Microbiol 13, 655-662 (1994); Lewis and Errington, Microbiology 142, 733-740 (1996); Lewis and Marston, Gene 227, 101-109 (1999); Feucht and Lewis, Gene 264, 289-297 (2001)). These techniques have been widely adopted by research groups involved in microbial cell biology, and the plasmid vectors have now been distributed directly to well over 100 laboratories world-wide, although they are now also distributed by the Bacillus Genetic Stock Centre. These techniques were instrumental in determining the establishment of compartment specificity of developmentally regulated s-factors during sporulation in B. subtilis (Lewis et al., PNAS 91, 3849-3853 (1994)). I also showed that prespore specific accumulation of the transcription regulator SpoIIAA was responsible for initiation of compartment-specific gene expression during development, that this accumulation was probably due to prespore-specific activity of the phosphatase SpoIIE, and that a programme of proteolysis was initiated following this activation event (Lewis et al., Genes Cell 1, 881-894 (1996); Lewis et al., J. Bacteriol 180, 3276-3284 (1998)). I was also involved in work that showed that the highly conserved SpoIIIE (FtsK) protein is a DNA translocase that moves DNA through a division septum (Wu et al., Genes Dev 9, 1316-1326 (1995)). This was the first example of such a phenomenon, and was a very significant finding as previously it was assumed that DNA was segregated into daughter cells/different compartments prior to division septum formation. Finally, I have shown that transcription and translation are spatially separated within bacteria (Lewis et al., EMBO J 19, 710-718 (2000)). This was an unexpected result as the 2 processes were thought to be very tightly coupled in bacteria. Furthermore, transcription becomes concentrated into a sub-fraction of the bacterial nucleoid at higher growth rates. These transcription foci have been shown to be the sites of rRNA synthesis, and my laboratory is now focussing on characterising transcription complexes and their structure in detail."

Research Interest

Medical Microbiology, Biochemistry and Cell Biology, Genetics