Poster: Late and Moved Abstracts

Abs # 958: Targeting of ATP-citrate lyase to the plastids of Arabidopsis thaliana

Presenter:	Babka, Heather L., hbabka@iastate.edu
Authors	Babka, Heather L. (A) (B)  Choi, Suh-Yeon  (A) (B)  Nikolau, Basil  J. (A) (C)  Syrkin Wurtele, Eve  (A) (B)
Affiliations:	(A): Iowa State University (B): Department of Genetics, Development, and Cell Biology (C): Department of Biochemistry and Biophysics

Acetyl-CoA is necessary for the production of many important plant chemicals, and since organelle membranes are impermeable to this large molecule, it must be synthesized in the compartment in which it will be utilized. The enzyme ATP-citrate lyase (ACL) produces a cytosolic pool of acetyl-CoA in the plant Arabidopsis thaliana. ACL catalyzes the ATP-dependent conversion of citrate and CoA to OAA and acetyl-CoA. Plastids are the site of fatty acid synthesis from acetyl-CoA; the expression of ACL in that organelle might, alter the rate of acetyl-CoA formation, and hence affect synthesis of fatty acids and other processes that require plastidic acetyl-CoA. The functional ACL enzyme consists of two subunits A and B (ACL-A and ACL-B respectively) individually encoded by genes named ACL-A1 and ACL-B2. ACL-A1 and ACL-B2 have been targeted to the plastids of A. thaliana using a transit peptide from the small subunit of Rubisco. Several lines have been obtained that are over-expressing the RNA for both ACL-A1 and ACL-B2. We are evaluating the protein levels and activity of the ACL enzyme in these lines, in concert with global expression studies, to understand how expression of the ACL gene in plastids may affect metabolite flux through acetyl-CoA-requiring metabolism in that organelle.