In our laboratory we study molecular aspects of transcription. Our main focus is on sigma factors – transcriptional regulatory proteins that are the master regulators of gene expression in bacteria. We are particularly interested in understanding the mechanism by which non-canonical sigma factors interact with RNA polymerase, target holoenzyme to promoter DNA, and stabilize open-complex promoter intermediates during the transcription initiation process.

Gaballa, A., MacLellan, S.R., and J.D. Helmann. 2011. Transcription activation by the siderophore sensor Btr is mediated by ligand-dependent stimulation of promoter clearance. Nucl.Acids.Res. NAR-02400-M-2011. In press. MacLellan, S.R., Guariglia-Oropeza, V., Gaballa, A. and J.D. Helmann. 2009. A two-subunit sigma factor activates transcription in Bacillus subtilis. PNAS. 106: 21323-21328. MacLellan, S.R., Eiamphungporn, W., and J.D. Helmann. 2008. ROMA: an in vitro approach to defining target genes for transcription regulators. Methods. 47: 73-77. MacLellan, S.R., Helmann, J.D., and H. Antelmann. 2008. Distribution and role of a newly identified sigma factor in the bacilli: YvrI is a component of the acid-stress response in Bacillus subtilis. J. Bacteriol. 191: 931-939. MacLellan, S.R., Wecke, T., and J.D. Helmann. 2008. A previously unidentified sigma factor and two accessory proteins regulate oxalate decarboxylase expression in Bacillus subtilis. Mol. Microbiol. 69: 954-967. MacLellan, S.R., MacLean, A.M., and T.M Finan. 2006. Promoter prediction in the rhizobia. Microbiology. 152: 1751-1763.