|Reverdatto, S - PURDUE UNIVERSITY BIOCHEM|
|Beilinson, V - PURDUE UNIVERSITY BIOCHEM|
Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2000
Publication Date: N/A
Technical Abstract: De novo fatty acid biosynthesis involves an ATP-dependent carboxylation of acetyl-CoA, a reaction catalyzed by the enzyme acetyl-CoA carboxylase. It is an important site for regulation of the carbon flux into fatty acid biosynthesis. Our research has focused on the multisubunit form of the plant enzyme that resides in soybean chloroplasts. It is composed of at least 4 subunits (BC, BCCP, alphaCT and betaCT). BetaCT is encoded by plastid DNA, while nuclear genes encode the other three subunits. Genomic DNAs corresponding to four alphaCT genes, 2 BC genes and 2 BCCP genes were sequenced. Potential regulatory elements associated with each gene were identified. We also determined the steady state mRNA levels characteristic of each gene, both in various soybean tissues and at different times during seed development and germination. Messages for alphaCT, BCCP and BC are of rare to medium abundance (15-155 times lower than ubiquitin mRNA). However, a 10-100 times more betaCT mRNA is present compared with the amount of the other ACCase subunits. Differences in mRNA amounts were present among family members at different times and in different tissues during soybean development. Moreover, alternative splicing occurs in the 5'-UTR of alphaCT1 maRNA.