Abstract: Gene Cloning and Structural Analysis of Biotin Carboxyl Carrier Protein Encoding Gene in Brassica napus DAI Xiao-feng, LU Chang-ming, WU Gang, WU Yu-hua, Xiao Ling (Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, Hubei, China, 430062) Abstract: Acyl-CoA carboxylase (ACCase) catalyzes the first step in the de novo biosynthesis of fatty acids. Biotin carboxyl carrier protein (BCCP), being one of the subunits of plastidial ACCase, controls the transferring of carboxyl from acetyl-CoA carboxylase to carboxyltransferase. In this study, we isolated bccp genes from genomic DNA of three winter-type cultivars of Brassica napus and analyzed their structural aspects of these genes in both DNA and protein levels, including length, intron distribution, hydrophobic conserved regions etc.. Results showed that there were at least 3 isoforms of bccp genes found in genomes of B.napus. Only one isoform bccp1 encodes a protein which is full in length and contains the domain for biotinylation, while the other two isoforms bccp2 and bccp3 encode proteins that are incomplete and lack of the domain for biotinylation. Further analysis revealed that both in bccp2 and bccp3 an adenine insertion resulted in a shift-frame mutation. This research provides scientific basis of bccp genes for genetic engineering and molecular marker-assisstant breeding.