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Address: 3-615C BSB
Phone: (319) 335-7622
Mentor: Craig D. Ellermeier, PhD
Undergraduate Institution: Virginia Tech
Extra-cytoplasmic function (ECF) sigma factors are an important stress response in a wide variety of bacteria. ECF sigma factors traditionally are co-transcribed with a transmembrane anti-sigma, which sequesters the sigma factor. Upon stress conditions, the anti-sigma is degraded by proteases causing derepression of the sigma factor. This initiates transcription of specific stress response genes.
Bacillus subtilis encodes seven ECF sigma factors. I study σV, which is induced by lysozyme stress. Lysozyme is an important component of the innate immune system that cleaves the β,1-4 linkage between N-acetyl-glucosamine and N-acetylmuramic acid. Interestingly, σV is also found in Enterococcus faecalis and Clostridium difficile. Both of these bacteria are intestinal pathogens and lysozyme resistance appears to be critical for survival during an infection. I am interested in understanding the process leading to σV activation and why activation is specific to lysozyme. Broadly this will impact our understanding of the mechanisms for ECF sigma factor activation. This is significant because it will provide insight into cell survival strategies that allow bacteria to infect a host or thrive in hostile environments.
Ho, T.D., Hastie, J.L., Intile, P.J., and Ellermeier, C.D. (2011). The Bacillus subtilis extracytoplasmic function sigma factor sigma(V) is induced by lysozyme and provides resistance to lysozyme. J Bacteriol 193, 6215-6222.
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