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Functional Genomics of Photosynthesis
Photosynthesis provides energy for most life on Earth, and as humans increasingly change this planet it is essential that we understand this process and the organisms which perform it. Our lab aims to dramatically accelerate our understanding of photosynthesis by applying novel functional genomics strategies to the green alga Chlamydomonas reinhardtii.
Chlamydomonas an ideal model organism for photosynthesis research.
The green plant photosynthetic apparatus is highly conserved and thus can be studied in Chlamydomonas. Chlamydomonas has several advantages over higher plants, which make it particularly convenient for using molecular biology and genetics tools to study photosynthesis. Specific features include:
1) Its ability to grow as a haploid and in the absence of a functional photosynthetic apparatus simplifies rapid isolation of mutants of interest.
2) Its nuclear genome has recently been sequenced, allowing the use of comparative genomics and enabling mapping of insertional mutants.
3) Its unicellular nature and short doubling time enable higher throughput experiments than alternative systems.
4) It has been used to study photosynthesis for over half a century and as a result is supported by extensive literature and a highly collaborative community.
Hundreds of conserved genes with putative roles in photosynthesis remain uncharacterized.
The recent publication of the Chlamydomonas nuclear genome [1] identified 349 genes with putative roles in photosynthesis, defined as being highly conserved among green plants including Arabidopsis thaliana, but not present in non-photosynthetic organisms. Strikingly, the functions of 214 of these genes are unknown. What are these genes doing? How are they organized into pathways?
We are developing transformative genomics tools to gain insight into the functions of Chlamydomonas genes.
Recently, powerful new tools have led to a revolution in how poorly characterized genes are studied in the budding yeast Saccharomyces cerevisiae. Systematic measurement of genetic interactions [2,3], protein localizations [4] and physical interactions [5] have led to an abundance of clues for the functions of nearly all proteins in the yeast genome. These clues have enabled the discovery and characterization of a variety of novel processes, for example novel endocytic structures called Eisosomes [6] and a novel tether between the mitochondria and endoplasmic reticulum [7]. We are developing novel high-throughput genetics tools for Chlamydomonas and using them to open doors to the characterization of new pathways and components with roles in photosynthesis.
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References:
[1] Merchant et al. The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science (New York, NY) (2007) vol. 318 (5848) pp. 245-50
[2] Tong et al. Systematic genetic analysis with ordered arrays of yeast deletion mutants. Science (New York, NY) (2001) vol. 294 (5550) pp. 2364-8
[3] Schuldiner et al. Exploration of the function and organization of the yeast early secretory pathway through an epistatic miniarray profile. Cell (2005) vol. 123 (3) pp. 507-19
[4] Huh et al. Global analysis of protein localization in budding yeast. Nature (2003) vol. 425 (6959) pp. 686-91
[5] Krogan et al. Global landscape of protein complexes in the yeast Saccharomyces cerevisiae. Nature (2006) vol. 440 (7084) pp. 637-43
[6] Walther et al. Eisosomes mark static sites of endocytosis. Nature (2006) vol. 439 (7079) pp. 998-1003
[7] Kornmann et al. An ER-mitochondria tethering complex revealed by a synthetic biology screen. Science (2009) vol. 325 (5939) pp. 477-81