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Indiana University Bloomington

Department of Biology

Faculty & Research

Faculty Profile

Yves Brun

Photo of Yves Brun
Research Images
Research photo by Yves Brun

Caulobacter crescentus predivisional cell.

Research photo by Yves Brun

Stalked bacteria. Clockwise from top left: Caulobacter crescentus, Asticcacaulis biprosthecum, Ancalomicrobium adetum, and Hyphomonas neptunium. From Wagner and Brun (2007), Mol. Micro. 64:28-33.

Clyde Culbertson Professor of Biology
Contact Information
By telephone: 812-855-8860/5-7239(lab)
JH 447G / JH 447F (lab)

Brun Lab website

Program
Microbiology
Research Areas
  • Evolution
  • Genomics and Bioinformatics
  • Microbial Cell Biology and Environmental Responses
  • Microbial Interactions and Pathogenesis
Education

Ph.D., Université Laval, Québec, Canada, 1990
Postdoctoral Fellow, Stanford University, 1990-93

Awards
1997, Senior Class Award for Teaching Excellence in Biology
1998-2003, National Science Foundation CAREER Award
1999, Department of Biology Teaching Excellence Recognition Award
2001, Indiana University Trustees Teaching Award.
2003-2007, Editor, Journal of Bacteriology
2005, IBASM Academic Scientific Achievement Award
2006, Top 2006 Stories in Science by The Future of Things
2010, Fellow of the American Academy of Microbiology
2012, Fellow of the American Association for the Advancement of Science
2014, Indiana University Outstanding Faculty Collaborative Research Award
2014, Fulbright US Research Scholar Award
2015, American Society for Microbiology Divisional Lecturer 
Research Description

Our research interests and experimental approaches range widely. We work to answer questions about bacterial development and life history, including the mechanisms that underlie observed phenotypes, and the evolutionary forces that shape them:

  • How do bacteria regulate the complex task of differentiation to create distinct cell types and morphologies?
  • How do individual bacteria coordinate their adhesion to surfaces? What role does adhesion play in community ecology?
  • Why do bacteria age, and what mechanisms drive the aging process?

As a model, we study the simple differentiating bacterium Caulobacter crescentus in which each cell division produces a motile swarmer cell and a stalked cell. In addition to differences in morphology, the two progeny cells have different fates. Only the stalked cell is competent to replicate DNA and divide. We increasingly study non-model bacterial species related to Caulobacter in order to bring an evolutionary perspective to our studies.

Caulobacter is easy to grow, has excellent genetics and a sequenced genome, and is ideally suited for cell biological approaches. We use a multitude of approaches that include mathematical modeling, biophysics, biochemistry, molecular biology, cell biology, microscopy, genetics, genomics, and proteomics. Our wide range of expertise and excellent collaborators allow us to focus on biological questions rather than specific methods and provides an outstanding multidisciplinary environment.

Regulation of cell differentiation. The different stages of polar development in Caulobacter are tightly coordinated with the cell cycle. We study transcriptional and proteolytic regulatory mechanisms and regulators that control the timed and ordered progression of these stages. We also study a checkpoint that couples polar development with cell division.

Control of cellular asymmetry. Before they divide, Caulobacter cells are asymmetric with a flagellum at one pole and a stalk and adhesive holdfast at the other pole. We have used genetic and molecular methods to identify genes that are involved in the maintenance of cellular asymmetry and we are studying their mechanism of action. We also have a strong interest in the mechanisms that target proteins and structures to a specific pole of the cell

Bacterial adhesion and biofilm formation. Adhesion is an important component of bacterial infections and is the first step of biofilm formation. In Caulobacter, adhesion is mediated by the holdfast, a complex polysaccharide with strong adhesive properties found at the tip of the stalk. We study the mechanism and regulation of single cell attachment to surfaces, holdfast synthesis, and the subsequent events that lead to the formation of biofilms.

Evolutionary genomics. We are taking advantage of next generation sequencing methods to sequence the genome of bacteria closely related to Caulobacter to investigate the evolution of cell shape and differentiation and the regulatory networks that control them. Towards this goal, we are isolating bacteria related to Caulobacter from a variety of environments using a phylogeny based screen to avoid the bias due to isolations based on phenotype.

Bacterial aging. Recent work has shown that organisms previously thought to be immortal, such as bacteria, demonstrate age-specific declines in reproduction. Asymmetry is thought to be important for aging by allowing the preferential segregation of damaged molecules to mother cells. We are using the asymmetrically dividing Caulobacter and close relatives that divide by the even more asymmetric mechanism of budding such as Hyphomonas to address the mechanism of aging and the role of asymmetry in this process.

Select Publications
Ducret, A., E.M. Quardokus, and Y.V. Brun. 2016. MicrobeJ, a tool for high throughput bacterial cell detection and quantitative analysis. Nature Microbiology, in press.
George Liechti, Erkin Kuru, Mathanraj Packiam, Jonathan T. Rittichier, Srinivas Tekkam, Edward Hall, Yen-Pang Hsu, Michael S. VanNieuwenhze, Yves V. Brun, Anthony T. Maurelli. 2016. Pathogenic Chlamydia lack a "classical" sacculus but synthesize a narrow, midcell peptidoglycan ring, regulated by MreB, for cell division. PLoS Pathogens, in press. 
Kuru, E., S. Tekkam, E. Hall, Y.V. Brun, and M.S. VanNieuwenhze. 2015. Synthesis of fluorescent D-amino acids (FDAAs) and their use for probing peptidoglycan synthesis and bacterial growth in situ. Nature Protocols, 10, 33-52. 
Hoffman, M.D., L.I. Kacz, P.J.B. Brown, D.T. Kysela, Y.V. Brun, and S.C. Jacobson. 2015. Timescales and Frequencies of Reversible and Irreversible Adhesion Events of Single Bacterial Cells. Analytical Chemistry, 87:12032-9. 
C. Jiang, P.J.B. Brown, A. Ducret, and Y.V. Brun. 2014. Sequential evolution of bacterial morphology by co-option of a developmental regulator. Nature, 506, 489-93. 
Curtis, P.D. and Y.V. Brun. 2014. Identification of essential Alphaproteobacterial genomes reveals functional variability in conserved developmental and cell cycle systems. Molecular Microbiology, 93:713-35
G. Liechti, E. Kuru, E. Hall, A. Kalinda, Y.V. Brun, M. VanNieuwenhze, and A. Maurelli. 2014. A new metabolic cell wall labeling method reveals peptidoglycan in Chlamydia trachomatis. Nature, 506, 507-10.
Javens, J.J., Z. Wan, G.G. Hardy, and Y.V. Brun. 2013. Bypassing the need for subcellular localization of a polysaccharide export-anchor complex by overexpressing its protein subunits. Molecular Microbiology, 89: 350-71. 
C. Berne, X. Ma, N. Licata, B. Neves, S. Setayeshgar, Y.V. Brun, and B. Dragnea. 2013. Physiochemical Properties of Caulobacter crescentus Holdfast: a Localized Bacterial Adhesive. Journal of Physical Chemistry, 117: 10492-503. 
Hughes, H.V., J.P. Lisher, G.G. Hardy, D.T. Kysela, R.J. Arnold, D.P. Giedroc, and Y.V. Brun. 2013. Coordinate synthesis and protein localization in a bacterial organelle by the action of a penicillin-binding-protein. Molecular Microbiology, 90, 1162-1177. 
Madren, S.M., M.D. Hoffman, P.J.B. Brown, D.T. Kysela, Y.V. Brun and S.C. Jacobson. 2012. Microfluidic device for automated synchronization of bacterial cells. Analytical Chemistry, 84(20):8571-8, DOI: 10.1021/ac301565g. [Chemical & Engineering News feature]  [article]
Kuru, E., H.V. Hughes, P.J.B. Brown, E. Hall, S. Tekkam, F. Cava, M.A. de Pedro, Y.V. Brun, and M.S. VanNieuwenhze. 2012. In situ Probing of Newly Synthesized Peptidoglycan in Live Bacteria with Fluorescent D-Amino Acids. Angewandte Chemie,  51(50):12519-23. DOI: 10.1002/anie.201206749. [Press release][Chemical and Engineering News feature][NIH Biomedical Beat Feature][Nature Reviews Microbiology feature][Nature Chemistry feature][NPR A Moment of Science]  [article]
Brown, P.J.B., M.A. de Pedro, D.T. Kysela, C. Van der Henst, J. Kim, X. De Bolle, C. Fuqua, and Y.V. Brun. 2012. Polar growth in the Alphaproteobacterial Order Rhizobiales. PNAS, 109: 1697-1701.
Li, G., Brown, P.B., J.X. Tang, Zhu, J., Quardokus, E.M., Fuqua, C., and Y.V. Brun.  2012.  Surface contact stimulates the just-in-time deployment of bacterial adhesins. Molecular Microbiology, 83:41-51. [MicroCommentary] [Press release] [NIH Biomedical Beat feature]    [article]
Berne, C., D. Kysela, and Y.V. Brun. 2010.  A bacterial extracellular DNA inhibits settling of motile progeny cells within a biofilm.  Molecular Microbiology, 77: 815-829.
Hughes, V., E., Huitema, S., Pritchard, K.C., Keiler, Y.V., Brun, and P. Viollier.  2010.  Protein localization and dynamics within a bacterial organelle.  PNAS, 107:5599-604. [abstract]
Li, Z., M. Trimble, Y.V. Brun, and G. Jensen.  2007.  The structure of FtsZ filaments in vivo suggests a force-generating role in cell division.  The EMBO Journal, 26, 4694-4708.  
Tsang, P., G. Li, Y.V. Brun, B. Freund, and J. X. Tang. 2006. Adhesion of single bacterial cells in the micronewton range. PNAS, 103: 5764-68. [abstract][Press release]
Wagner, J.K., S. Setayeshgar, L. Sharon, J. Reilly, and Y.V. Brun. 2006. A nutrient uptake role for bacterial cell envelope extensions. PNAS, 103: 11772-11777. [abstract][Press release][Commentary]
Lawler, M.L., D.E. Larson, A.J. Hinz, D. Klein, and Y.V. Brun.  2006.  Dissection of Functional Domains of the Polar Localization Factor PodJ in Caulobacter crescentus.  Molecular Microbiology, 59: 301-316.
Hinz, A. J., D. E. Larson, C. S. Smith, and Y. V. Brun. 2003.  The Caulobacter crescentus polar organelle development protein PodJ is differentially localized and is required for polar targeting of the PleC development regulator.  Molecular Microbiology, 47: 929-941. 
Wortinger, M., M. Sackett, and Y. V. Brun.  2000.  CtrA mediates a DNA replication checkpoint that prevents cell division in Caulobacter.  EMBO J., 19: 4503-4512.

Kelly, A.J., M. Sackett, N. Din, E. Quardokus, and Y.V. Brun, Cell cycle dependent transcriptional and proteolytic regulation of FtsZ in Caulobacter.  1998.  Genes and Development, 12:  880-893.

Quardokus, E, N. Din, and Y.V. Brun.  1996.  Regulation and cell type specific localization of the FtsZ division initiation protein in Caulobacter.  PNAS USA, 93, p. 6314-6319.

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