Presenter(s): Carolyn Brewster – Biology, Math and Computer Science
Faculty Mentor(s): Alice Barkan
Poster 51
Research Area: Natural/Physical Science
Funding: O’Day Fellowship
Photosynthesis provides the fuel for earth’s biomes. The protein PsbA is essential for photosynthesis but is also damaged as a consequence of photosynthesis; PsbA must therefore be constantly replaced to maintain photosynthetic activity. Accordingly, PsbA synthesis increases dramatically within minutes after shifting plants from dark to light. The mechanisms underlying this response are not known. We are investigating these mechanisms with a two-pronged approach: we are studying proteins that we suspect may be involved in PsbA light-regulation, and we are designing protein “tags” to isolate potential regulators that are attached to PsbA mRNA. We identified two candidate regulators, HCF244 and TPJ1, based on their patterns of gene expression. Using a combination of techniques, we discovered that HCF244 is required for PsbA synthesis whereas TPJ1 is not. We found that TPJ1 activates production of a different protein involved in photosynthesis. Thus, HCF244 is a good candidate for regulating PsbA synthesis in response to light, but TPJ1 is not. In the second approach, we designed a method to engineer proteins to bind specifically to the PsbA RNA. We expressed these engineered proteins in plants and confirmed that they bind specifically to PsbA RNA in vivo. We are using these proteins as “hooks” to purify PsbA RNA and the proteins bound to it. These will be evaluated for their role in PsbA regulation. In addition to elucidating mechanisms that regulate production of the photosynthetic apparatus, this is the first demonstration that proteins can be designed to purify specific RNA-protein particles from an organism.