Developing genome-editing techniques to investigate biomineralisation in coccolithophores (CASE)

Dr Fabio Nudelman - University of Edinburgh - School of Chemistry
Dr Elise Cachat - University of Edinburgh - School of Biological Sciences
Prof Dominic Campopiano - University of Edinburgh - School of Chemistry

Project description:

Biomineralisation is the dynamic process whereby an organism employs a range of specialized proteins, lipids and polysaccharides to control mineral precipitation and produce a functional mineralised structure. Coccolithophores are unicellular marine algae that produce coccoliths – disk-shaped assemblies of calcium carbonate crystals in the form of calcite – that play an important role in the global carbon cycle, allowing the excess greenhouse CO2 to be removed from Earth atmosphere through photosynthesis and calcification. The formation of the calcite disks is a fascinating process that is carried out within mineralisation vesicles inside the cells, where polysaccharides are thought to control the nucleation, growth and morphology of the crystals (Sviben et al, 2016). Once the mineralisation is complete, the vesicle is transported to the cell membrane and the mature mineral is extruded. An interesting aspect in this process is that the size and complexity of the calcite disks are genetically controlled, such that different species produce scales with different morphologies. While the roles of the polysaccharides in controlling crystal nucleation and growth have been investigated over several years, the biochemical pathways that control mineralisation are still unknown. In particular, genetic models that will enable a detailed in vivo study of the specific role of particular proteins and signalling pathways to biomineralisation are lacking in coccolithophores.

Two recent developments have opened up a new and largely unexplored route of genetic manipulation in these microorganisms: (i) Endo et al. published the first method for DNA nuclear transfer in Pleurochrysis carterae, a member of the coccolithophore family (Endo et al., 2016); and (ii) the genome of the dominant coccolithophore Emiliania huxleyi was sequenced and published (Read et al. 2013). This project aims at building upon these recent advances to:
1.develop efficient methods of genome-editing in these coccolithophorid algae;
2.engineer fluorescently-tagged reporter models for key components of the mineralisation vesicle (e.g. actin, tubulin);
3.monitor by real time fluorescent microscopy the transport and extrusion of mineralisation vesicles in different species.
4.Investigate the role of sphingolipid biosynthesis and trafficking in this transport.

Training: The supervisory team of this project merges expertise in chemistry/biomineralisation (FN), sphingolipid metabolism (DC) and molecular genetics (EC), which, in addition to training in scientific research and analytical methods, will ensure the acquisition of skills in several areas, including electron microscopy and crystallography, cell culture, cellular and molecular biology techniques and fluorescence/confocal microscopy.

This project is a 48-month EastBIO PhD studentship, supporting all UK/EU tuition and fees and a stipend at current BBSRC levels (2017/18 rate is £14,553). The candidate must satisfy BBSRC studentship eligibility requirements, having settled status in the UK and having been ‘ordinarily resident’ in the UK for 3 years prior to the start of the studentship. The ideal PhD candidate will be a recent or upcoming graduate (Honours degree with a result of 2:1 or higher) in a related subject and a willingness to learn in a multi-disciplinary environment. The successful candidate will have a demonstrated ability to work well in a team, excellent oral and written communication skills and an inherent desire to learn and strive to develop as a scientist and leader. The position will be based in the EaStCHEM School of Chemistry in Edinburgh.

For further details, please contact Fabio Nudelman at [Email Address Removed]. To apply please send your CV along with the names and contact details of two referees to the above email address.

Applications will be reviewed as they are submitted.

The closing date for applications is 22 May 2017.