title: Functional analysis and tissue-differential expression of four FAD2 genes in amphidiploid Brassica napus derived from Brassica rapa and Brassica oleracea.
abstract: Fatty acid desaturase 2 (FAD2), which resides in the endoplasmic reticulum (ER), plays a crucial role in producing linoleic acid (18:2) through catalyzing the desaturation of oleic acid (18:1) by double bond formation at the delta 12 position. FAD2 catalyzes the first step needed for the production of polyunsaturated fatty acids found in the glycerolipids of cell membranes and the triacylglycerols in seeds. In this study, four FAD2 genes from amphidiploid Brassica napus genome were isolated by PCR amplification, with their enzymatic functions predicted by sequence analysis of the cDNAs. Fatty acid analysis of budding yeast transformed with each of the FAD2 genes showed that whereas BnFAD2-1, BnFAD2-2, and BnFAD2-4 are functional enzymes, and BnFAD2-3 is nonfunctional. The four FAD2 genes of B. napus originated from synthetic hybridization of its diploid progenitors Brassica rapa and Brassica oleracea, each of which has two FAD2 genes identical to those of B. napus. The BnFAD2-3 gene of B. napus, a nonfunctional pseudogene mutated by multiple nucleotide deletions and insertions, was inherited from B. rapa. All BnFAD2 isozymes except BnFAD2-3 localized to the ER. Nonfunctional BnFAD2-3 localized to the nucleus and chloroplasts. Four BnFAD2 genes can be classified on the basis of their expression patterns.
authors.affiliation: Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA, Suwon 441-707, Republic of Korea.
authors.forename: Kyeong-Ryeol
authors.initials: KR
authors.lastname: Lee
authors.forename: Soo
authors.initials: S
authors.lastname: In Sohn
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Jung
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Roh
authors.forename: Jong-Bum
authors.initials: JB
authors.lastname: Kim
authors.forename: Mi Chung
authors.initials: MC
authors.lastname: Suh
authors.forename: Hyun Uk
authors.initials: HU
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D001937:Brassica / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029688:Brassica napus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029741:Brassica rapa / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004171:Diploidy; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D017343:Genes, Plant / Q000502:physiology; D049810:Genetic Speciation; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D044943:Fatty Acid Desaturases; C040448:delta-12 fatty acid desaturase
keywords: ALA; BSA; Brassica napus; Brassica oleracea; Brassica rapa; DAP; DNA complementary to RNA; EDTA; ER; FAD2; FAME; LA; MYA; ORF; Oilseed rape; Oleate 12-desaturase; PC; PUFA; QTL; SDS; SSC; TM; UTR; aa; amino acid; base pair; bovine serum albumin; bp; cDNA; days after pollination; eYFP; endoplasmic reticulum; enhanced yellow fluorescent protein; ethylenediaminetetraacetic acid; fatty acid methyl ester; kb; kilo base; linoleic acid; million years ago; nt; nucleotide; open reading frame; phosphatidylcholine; polyunsaturated fatty acid; quantitative trait loci; sodium chloride-sodium citrate; sodium dodecylsulfate; transmembrane; untranslated region; α-linolenic acid