Dissecting the molecular mechanism of directional centromere DNA segregation in Caulobacter Crescentus

• Applicant: Dr. Katja Zieske
• Subject Area: General Genetics and Functional Genome Biology ; Biophysics ; Metabolism, Biochemistry and Genetics of Microorganisms ; Cell Biology
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 289436718

• Final Report Year: 2020

Final Report Abstract

Chromosome segregation is an important process in all living systems, because it ensures the distribution of genetic material to progenitors. However, our knowledge about the detailed mechanisms of chromosome segregation is still incomplete. In this study, I characterized DNA segregation in the model bacterium Caulobacter crescentus. My main goal was to analyze critical molecular parameters that regulate directional DNA segregation. I hypothesized that in the bacterium Caulobacter crescentus the protein ParA and its interaction partner ParB (key players for chromosome segregation during cell division) together with the chromosomal DNA represent a minimal system for dynamic pattern formation and directed transport of DNA. To test this hypothesis and characterize the dynamics of the Caulobacter Par system I reconstituted the dynamic localization of Caulobacter Par proteins within giant E.coli cells, that don’t have an own Par protein system and are chemically enlarged. In these bacteria, in which the Caulobacter Par proteins are unlikely to interact specifically with further proteins, a dynamic wave-like redistribution of ParA was observed. In addition, the patterns were predominantly directed along the length axis of giant E. coli cells. Our results demonstrate that the Par protein system of Caulobacter crescentus is a minimal system for dynamic pattern formation. Moreover, out observations indicate that Caulobacter Par protein patterns intrinsically recognize the length axis of cells.

Publications

• (2016) Protein Patterns and Oscillations on Lipid Monolayers and in Microdroplets. Angew Chem Int Ed Engl.
  Zieske K, et al.
  
• (2017) Reconstitution of Protein Dynamics Involved in Bacterial Cell Division, Subcell Biochem
  Loose M, Zieske K, et al.
  
• (2019) Optogenetic control of cell morphogenesis on protein micropatterns
  Zieske K, Mullins RD