The Robertson Lab Members

Interests

I am a 2011 Biochemistry and Molecular Biology major at Clark. I am interested in working with plants and other photosynthetic eukaryotes and therefore I joined the Robertson lab in spring 2008.

Currently I am examining the role of RNA stability in the regulation of gene expression in marine diatoms. Diatoms are unicellular, photosynthetic, eukaryotic algae that inhabit oceans and freshwater ecosystems. Photosynthesis by marine diatoms generates as much as 45% of the 45 to 50 billion metric tons of organic carbon produced each year in the sea, and their role in the global carbon cycling is predicted to be comparable to that of all terrestrial rain forests combined (Armbrust, Berges et al. 2004). Diatoms are known to achieve rapid growth rates on nitrate as N source (Allen 2005) and therefore nitrate availability is a critical component in driving oceanic primary productivity. Previous work on diatoms has shown that  primary productivity driven by nitrate results in greater carbon export to deeper depths of the ocean compared to productivity driven by ammonium. A more detailed understanding of the molecular basis underpinning physiological responses to ammonium/nitrate interactions in different taxonomic classes of phytoplankton will enhance our ability to understand and predict patterns of phytoplankton activity and productivity in relation to nutrient availability (Allen 2005).

Previous work in the lab demonstrated that mRNA levels of several key nitrogen assimilatory enzymes decrease after addition of ammonium to the cell cultures. My goal is to identify the stabilizing/destabilizing regions in the mRNA transcripts of the enzymes and to understand at the molecular level, the interaction between ammonium and nitrate assimilation.   To identify conserved regulatory regions, I am using molecular and bioinformatics approaches simultaneously. Advanced servers available on the web allow us to search for putative RNA binding motifs in the 3’-UTR. Also, I am am cloning the 3’-UTRs of several genes to help characterize RNA binding proteins that alter mRNA stability in vivo.  

References:

Allen, A. E. (2005). "Beyond sequence homology: redundant ammonium transporters in a marine diatom are not functionally equivalent." Journal of Phycology 41(1): 4-6. 2.

Armbrust, E. V., J. A. Berges, et al. (2004). "The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism." Science 306(5693): 79-86.