Xanthomonas citri subsp. citri (X. citri) is the causal agent of citrus canker, a disease that affects all commercial varieties of citrus and that has a great impact on the world's orange production. Whilst the genome of X. citri has been available for 20 years and this bacterium is being studied to the point of becoming a prokaryotic model, very little is known about its mechanisms of cell division and chromosome segregation. Many of the proteins involved in such processes are essential and generally unique in bacteria, or have distant functional analogs in derived eukaryotes. This fact makes chromosome division and segregation proteins excellent targets for the development of antibacterials to control pathogens, which may be relative safety for their host(s). The main constituent of the bacterial cell division machinery (divisome) is the FtsZ protein. FtsZ is the ancestral, prokaryotic tubulin, capable of polymerizing and forming the Z-ring, which is positioned centrally in dividing cells (septal region). The Z-ring functions as a scaffold that recruits several other proteins necessary for the division and coordination of membrane invagination and septal wall synthesis. For cell division to occur effectively, chromosomes must be segregated into daughter cells with the release of the central cell space. It is believed that there is a crosstalk between division/segregation, where proteins function as checkpoints to assess stages and free other subsequent processes. In Escherichia coli, the terminal region of the chromosome (Ter) plays an important role in maintaining the geometry and stability of the Z-ring. Such a region has cis matS sites that are linked by a protein designated MatP. MatP is responsible for stabilizing and anchoring the termination region to the divisome via interaction with the ZapB/ZapA proteins, which, in turn, bind to the Z-ring. In this study, we aim to identify whether there is a functional analog of MatP in X. citri by immunoprecipitation using GFP-ZapB as bait. We also hope to explore the protein network of interaction communicating the processes of chromosome division and segregation in this bacterium.
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