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Glen Wheeler

PML Senior Scientist
MBA Associate Fellow
Email: glw@pml.ac.uk
Telephone: 01752 633250

Algal signalling group

We are interested in the signalling mechanisms algae use to respond to their environment and how algae may be used as model organisms to study fundamental signalling processes in eukaryotes.

BBSRC post-doc position available

Current research projects

Ca²⁺ signalling in cilia and flagella

Cell biologists are becoming increasingly aware that cilia and flagella are important sensory organelles, which detect changes in the extracellular environment and convey these signals to the cell body. The biflagellate green alga, Chlamydomonas, is a model organism for the study of flagella function and has allowed researchers to link ciliary dysfunction to a range of human genetic disorders. We are using molecular, biochemical and cell physiological techniques to study signalling processes in Chlamydomonas flagella. We have recently developed techniques to image Ca²⁺ in both the cytosol and the flagella of Chlamydomonas and have demonstrated that these green algae exhibit very rapid localised Ca²⁺ elevations during the process of flagellar excision (Wheeler et al, 2008).

The evolution of ion channels

Eukaryote algae represent many diverse phylogenetic groups and therefore contain a wealth of genomic information relating to the evolution of fundamental cellular processes. Many ion channels associated with animal signalling processes are also present in the genomes of unicellular photosynthetic algae, including the voltage-gated Ca²⁺ channels, TRP channels and inositol triphosphate receptors (Wheeler and Brownlee, 2008). We are using comparative genomic approaches in combination with physiological studies to understand the evolutionary origins of these ion channels and their roles in algae.

Molecular mechanisms of calcification in coccolithophores

Coccolithophores are abundant bloom-forming phytoplankton which play are important role in the global carbon cycle due to their ability to produce calcium carbonate plates, known as coccoliths. Changes in the chemistry of our oceans caused by increased atmospheric CO₂ may have a significant impact on coccolithophore calcification. In order to help predict how coccolithophores will respond to these rapid changes in their environment, we are examining how calcification is regulated at the cellular level. We are using genomic and physiological techniques in coccolithophores to determine the cellular mechanisms responsible for calcification and how these mechanisms may respond to environmental change.

Signalling between algae and bacteria - Vitamin B₁₂ nutrition

Many important marine algae require vitamin B₁₂ for growth. Eukaryotes cannot synthesise vitamin B₁₂ and this co-factor must therefore be obtained from bacterial sources. However, only 50% of algal species require B₁₂ and it appears B₁₂ dependence has arisen independently in many different lineages throughout evolution. In collaboration with Prof Alison Smith (University of Cambridge), we are examining the cellular mechanisms responsible and the nature of the interaction between algae and bacteria.

Algal attraction to bacterial quorum sensing signals

Algae are major contributors to the biofouling of shipping and other man-made structures in the marine environment. In collaboration with Dr Ian Joint and Dr Karen Tait (Plymouth Marine Laboratory), we have found that zoospores of the green macroalga, Ulva, are attracted to quorum sensing signals (acyl-homoserine lactones) produced by bacterial biofilms (Wheeler et al, 2006). We are examining the signalling mechanisms in green algae which mediate chemoattraction to acyl-homoserine lactones.

Publications:

• Verret F, Taylor A, Wheeler G, Farnham G, Brownlee C. Calcium channels and their implications for evolution of calcium-based signalling in photosynthetic eukaryotes. New Phytologist - in press.
• Mackinder L, Wheeler G, Schroeder D, Riebesell U, Brownlee C. Molecular mechanisms underlying calcification in coccolithophores. Geomicrobiology - in press
• Qudeimat E, Faltusz AM, Wheeler G, Lang D, Brownlee C, Reski R, Frank W. A PIIB-type Ca²⁺-ATPase is essential for stress adaptation in Physcomitrella patens. Proc. Natl. Acad. Sci. USA. 2008. 105(49) 19554-19559.
• Wheeler GL, Brownlee C. Ca²⁺ signalling in plants and green algae - changing channels. Trends Plant Sci. 2008. 13(9):506-14
• Wheeler GL, Miranda-Saavedra D, Barton GJ. Genome Analysis of the Unicellular Green Alga Chlamydomonas reinhardtii Indicates an Ancient Evolutionary Origin for Key Pattern Recognition and Cell-Signaling Protein Families. Genetics. 2008. 179(1):193-7.
• Wheeler GL, Joint I, Brownlee C. Rapid spatiotemporal patterning of cytosolic Ca²⁺ underlies flagellar excision in Chlamydomonas reinhardtii. Plant J. 2008. 53(3):401-13.
• Thompson SE, Callow JA, Callow ME, Wheeler GL, Taylor AR, Brownlee C. Membrane recycling and calcium dynamics during settlement and adhesion of zoospores of the green alga Ulva linza. Plant Cell Environ. 2007. 30(6):733-44.
• Joint I, Tait K, Wheeler G. Cross-kingdom signalling: exploitation of bacterial quorum sensing molecules by the green seaweed Ulva. Philos Trans R Soc Lond B Biol Sci. 2007. 362(1483):1223-33.
• Conklin PL, Gatzek S, Wheeler GL, Dowdle J, Raymond MJ, Rolinski S, Isupov M, Littlechild JA, Smirnoff N. Arabidopsis thaliana VTC4 encodes L-galactose-1-P phosphatase, a plant ascorbic acid biosynthetic enzyme. J Biol Chem. 2006. 281(23):15662-70.
• Bothwell JHF, Brownlee C, Hetherington AM, Ng CK, Wheeler GL, McAinsh MR. Biolistic delivery of Ca²⁺ dyes into plant and algal cells. Plant J. 2006. 46(2):327-35.
• Wheeler GL, Tait K, Taylor A, Brownlee C, Joint I. Acyl-homoserine lactones modulate the settlement rate of zoospores of the marine alga Ulva intestinalis via a novel chemokinetic mechanism. Plant Cell Env. 2006. 29(4):608-18.
• Wheeler GL, Grant CM. Regulation of redox homeostasis in the yeast Saccharomyces cerevisiae. Physiol. Plant. 2004 120(1):12-20.
• Wheeler GL, Trotter EW, Dawes IW, Grant CM. Coupling of the transcriptional regulation of glutathione biosynthesis to the availability of glutathione and methionine via the Met4 and Yap1 transcription factors. J Biol Chem. 2003 278(50):49920-8.
• Wheeler GL, Quinn KA, Perrone G, Dawes IW, Grant CM. Glutathione regulates the expression of gamma-glutamylcysteine synthetase via the Met4 transcription factor. Mol Microbiol. 2002. 46(2):545-56.
• Collinson EJ, Wheeler GL, Garrido EO, Avery AM, Avery SV, Grant CM. The yeast glutaredoxins are active as glutathione peroxidases. J Biol Chem 2002. 277(19):16712-7.
• Gatzek S, Wheeler GL, Smirnoff N. Antisense suppression of L-galactose dehydrogenase in Arabidopsis thaliana provides evidence for its role in ascorbate synthesis and reveals light modulated L-galactose synthesis. 2002. Plant J. 30(5):541-53.
• Smirnoff N and Wheeler GL. Ascorbic acid in plants: biosynthesis and function. Crit Rev Biochem Mol Biol 2000. 35(4):291-314
• Conklin PL, Norris SR, Wheeler GL, Williams EH, Smirnoff N and Last RL. Genetic evidence for the role of GDP-mannose in plant ascorbic acid (vitamin C) biosynthesis. Proc. Natl. Acad. Sci. USA 1999. 96:4198-4203
• Wheeler GL, Jones MA and Smirnoff N. The biosynthetic pathway of vitamin C in higher plants. Nature 1998. 393:365-369

Book chapters:

• Smirnoff N and Wheeler GL. Ascorbic acid metabolism in plants. In Plant Carbohydrate Biochemistry. 1999. eds JA Bryant, MM Burrell, NJ Kruger. pp 215-229, Oxford:BIOS Sci Publ.