Genes encoding the alpha-carboxyltransferase subunit of acetyl-CoA carboxylase from Brassica napus and parental species: cloning, expression patterns, and evolution.
Heteromeric acetyl coenzyme A carboxylase (ACCase), a rate-limiting enzyme in fatty acid biosynthesis in dicots, is a multi-enzyme complex consisting of biotin carboxylase, biotin carboxyl carrier protein, and carboxyltransferase (alpha-CT and beta-CT). In the present study, four genes encoding alpha-CT were cloned from Brassica napus, and two were cloned from each of the two parental species, B. rapa and B. oleracea. Comparative and cluster analyses indicated that these genes were divided into two major groups. The major divergence between group-1 and group-2 occurred in the second intron. Group-2 alpha-CT genes represented the ancestral form in the genus Brassica. The divergence of group-1 and group-2 genes occurred in their common ancestor 12.96-17.78 million years ago (MYA), soon after the divergence of Arabidopsis thaliana and Brassica (15-20 MYA). This time of divergence is identical to that reported for the paralogous subgenomes of diploid Brassica species (13-17 MYA). Real-time reverse transcription PCR revealed that the expression patterns of the two groups of genes were similar in different organs, except in leaves. To better understand the regulation and evolution of alpha-CT genes, promoter regions from two sets of orthologous gene copies from B. napus, B. rapa, and B. oleracea were cloned and compared. The function of the promoter of gene Bnalpha-CT-1-1 in group-1 and gene Bnalpha-CT-2-1 in group-2 was examined by assaying beta-glucuronidase activity in transgenic A. thaliana. Our results will be helpful in elucidating the evolution and regulation of ACCase in oilseed rape.
Li
Zhi-Guo
ZG
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Yin
Wei-Bo
WB
Guo
Huan
H
Song
Li-Ying
LY
Chen
Yu-Hong
YH
Guan
Rong-Zhan
RZ
Wang
Jing-Qiao
JQ
Wang
Richard R-C
RR
Hu
Zan-Min
ZM
D024506:5' Flanking Region / Q000235:genetics; D000103:Acetyl-CoA Carboxylase / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D029688:Brassica napus / Q000201:enzymology / Q000235:genetics*; D029741:Brassica rapa / Q000201:enzymology / Q000235:genetics; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D018628:Gene Dosage; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D018744:DNA, Plant; D010940:Plant Proteins; D021122:Protein Subunits; D000103:Acetyl-CoA Carboxylase