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PROJECT PROPOSAL for applicants for Ph.D. fellowships supervisor: institution: contact: CV: Bettina UGHYDSB, Ph.D. Institute of Plant Biology [email protected] http://www.brc.hu/file/cv/plant_ughy_bettina_en.pdf project title: CYANOBACTERIAL CELL DIVISION PROJECT SUMMARY The cell proliferation is one of the most fundamental processes of all organisms. Cell division in bacteria is initiated by a ring-like protein structure at midcell. The timing and positioning of the formation of the so-called Z-ring is crucial for cell divisions. Living organisms often have to confront with changing environment and they should adapt to different stress conditions. Bacterial cell morphology and division mechanism may change in response to environmental cues. The question is how the cell division factors control the division process in cyanobacteria, ancestors of plant plastids, under different environmental conditions. BACKGROUND OF THE STUDY Cyanobacteria are oxygenic photosynthetic bacteria that can be found in a wide range of habitats, which includes freshwater, marine, terrestrial and extreme environments. Cyanobacteria have appeared on the primordial Earth over three billion years ago and these photosynthetic microbes evolved an amazing arsenal of biochemical pathways that exert defence mechanisms and produce metabolites unique to them. Their high capability to adapt to the various environments may be related to their long evolutionary history. Cyanobacteria are believed to be the ancestor of higher plant plastids; therefore, they are good model organisms for investigation of photosynthetic processes and chloroplast development. They have high capability to adapt to changing environments by activating various strategies. Nowadays cyanobacteria are in the focus of intensive research because of their potential application in various fields of biotechnology. Cyanobacteria are involved in various applications that could help protecting the environment and diminishing the destructive effects of the industrial activities, moreover they can be the source of various natural products such as biofuel or biodegradable plastics. Cyanobacteria could be a source of new pharmaceutical compounds because they produce secondary metabolites with unique chemical structure. These bacteria also used as dietary supplement and in production of cosmetics. On the other hand toxin production of cyanobacteria could pose health hazard for humans and animals alike. Harmful algal and cyanobacterial blooms can caused severe problem both in marine and freshwater environments. Contamination by other organisms of the selected strains of cyanobacteria cultured in large-scale for consumption or for metabolite production could also cause trouble. Therefore appropriate and strict quality control is needed for safe growing and applications of these organisms. For most biotechnological applications production of high cyanobacterial biomass is needed. Cyanobacteria reproduce by binary fission (Figure 1). Cell division in bacteria is mediated by a macromolecular machinery known as divisome. The divisome formation is initiated by polymerization of the FtsZ protein forming the so-called Z-ring at the midcell. Several proteins involved in prokaryotic cell division were identified but the molecular mechanism of the division ring formation and positioning is still not fully elucidated. Correct positioning of the Z-ring is crucial for the cells. Certain cyanobacteria show nutrient-associated changes that included arrest of cytokinesis along with cell elongation, as well as asymmetric cell division once proliferative conditions were resumed. Nutrient limitation caused cell elongation of the Synechococcus sp. PCC7942 cyanobacterial cells. The detailed mechanism underlying the position of the divisome in symmetric fission of normal size cells as well as determination of the sites of division of elongated cells need to be elucidated in cyanobacteria. Also, the role and interactions of the cell division and its controlling proteins is not fully elucidated in cyanobacteria. RELEVANT RESEARCH IN THE HOST LABORATORY In the last few years our research was focused on the role of phosphatidylglycerol (PG) in cellular processes of cyanobacteria. We have demonstrated by characterization of PGdeficient cyanobacterial mutant strains that this phospholipid has important roles in the structure and function of photosynthetic complexes. Depletion of PG resulted in morphological changes causing cell elongation and arrested the cell division, suggesting its further role in cyanobacterial cell division. However, it is not known in detail how the lipid composition of membranes affects the division process and the function and interactions of proteins involved in this process. It also unclear how different environmental and stress conditions influence the cell division processes and how the participating proteins mediate cell division in cyanobacteria under different conditions. To this end, we are to investigate the cell fission and the role of cell division proteins in cyanobacteria under various conditions using molecular biological biophysical and biochemical techniques. Supported by the TÁMOP 4.1.1.C -13/1/KONV.2014-0001 project Dividing Synechococcus PCC7942 cyanobacterial cell, in which the division ring is visualised by the signal of the inserted GFP. SPECIFIC AIMS Green fluorescence protein (GFP) fusion proteins will be introduced into cyanobacteria to study cell division by monitoring their localization during cell fission under different conditions by confocal laser scanning microscopy (CLSM). Co-immune precipitation (co-IP) assays and Western blot hybridization will be used to investigate the interactions between the cell division proteins under different growth conditions. MATERIAL AND METHODS Basic molecular biology techniques such as cloning, DNA isolation, plasmid isolation and PCR. CLSM will be used to follow the localization of the GFP signals. Protein isolation, co-IP experiments and Western blot hybridization. SUGGESTED READINGS Miyagishima SY, et al.: Identification of cyanobacterial cell division genes by comparative and mutational analyses. Mol. Microbiol., 56(1):126-143(2005) Laczko-Dobos H, et al.: Role of phosphatidylglycerol in the function and assembly of photosystem II reaction center, studied in a cdsA inactivated PAL mutant strain of Synechocystis sp. PCC6803 that lacks phycobilsomes. BBA, 1777:1184-1194(2008) Bogos B, et al.: Phosphatidylglycerol depletion affects photosystem II activity in Synechococcus sp. PCC7942 cells. Photosynth. Res., 103:19-30(2009) Marbouty M, et al.: Characterization of the FtsZinteracting septal proteins SepF and Ftn6 in the spherical-celled cyanobacterium Synechocystis strain PCC 6803. J. Bacteriol., 191(19):6178-6185(2009) Miyagishima SY: Mechanism of plastid division: from a bacterium to an organelle. Plant Physiol., 155(4):15331544(2011) Marbouty M, et al.: The cyanobacterial cell division factor Ftn6 contains an N-terminal DnaD-like domain. BMC Struct Biol., 9:54(2009) Marbouty M, et al.: Characterization of the FtsZinteracting septal proteins SepF and Ftn6 in the spherical-celled cyanoacterium Synechocystis strain PCC 6803. J Bacteriol., 191:6178-6185(2009) Marbouty M, et al.: Characterization of the Synechocystis strain PCC 6803 penicillin-binding proteins and cytokinetic proteins FtsQ and FtsW and their network of interactions with ZipN. J Bacteriol., 191:5123-5133(2009) SNAPSHOTS FROM THE HOST LABORATORY Significant publications Sozer O, et al.: Proteins, glycerolipids and carotenoids in the functional photosystem II architecture. Front Biosci (Landmark Ed), 16:619-643(2011) Domonkos I, et al.: Carotenoids, versatile components of oxygenic photosynthesis. Prog Lipid Res., 52:539-561(2013) Nagy G, et al.: Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering. Biochem J., 436:225-230(2011) Nagy G, et al.: Chloroplast remodelling during state transitions in Chlamydomonas reinhardtii as revealed by noninvasive techniques in vivo. PNAS 111:5042-5047(2014) Representative recent research grants ”Role of phosphatidylglycerol in cyanobacterial cell fission” (OTKA-K 2010-2014) ”Structural and functional plasticity of thylakoid membranes” (OTKA-K 2015-2018) Some of the latest students in the laboratory Kóbori TO, ITC+Ph.D., 2011-2014; “Role of phosphatidylglycerol in cyanobacterial cell division” Sarvanan GK, ITC, 2014-recent; “Role of phosphatidylglycerol in cyanobacterial cell division and electron transport processes” Supported by the TÁMOP 4.1.1.C -13/1/KONV.2014-0001 project