James D W, Lim E, Keller J, Plooy I, Ralston E, Dooner H K
DNA Plant Technology Corporation, Oakland, California 94608.
Plant Cell. 1995 Mar;7(3):309-19. doi: 10.1105/tpc.7.3.309.
The FATTY ACID ELONGATION1 (FAE1) gene of Arabidopsis is required for the synthesis of very long chain fatty acids in the seed. The product of the FAE1 gene is presumed to be a condensing enzyme that extends the chain length of fatty acids from C18 to C20 and C22. We report here the cloning of FAE1 by directed transposon tagging with the maize element Activator (Ac). An unstable fae1 mutant was isolated in a line carrying Ac linked to the FAE1 locus on chromosome 4. Cosegregation and reversion analyses established that the new mutant was tagged by Ac. A DNA fragment flanking Ac was cloned by inverse polymerase chain reaction and used to isolate FAE1 genomic clones and a cDNA clone from a library made from immature siliques. The predicted amino acid sequence of the FAE1 protein shares homology with those of other condensing enzymes (chalcone synthase, stilbene synthases, and beta-ketoacyl-acyl carrier protein synthase III), supporting the notion that FAE1 is the structural gene for a synthase or condensing enzyme. FAE1 is expressed in developing seed, but not in leaves, as expected from the effect of the fae1 mutation on the fatty acid compositions of those tissues.
拟南芥的脂肪酸延长酶1（FAE1）基因是种子中极长链脂肪酸合成所必需的。推测FAE1基因的产物是一种缩合酶，可将脂肪酸的链长从C18延长至C20和C22。我们在此报告通过用玉米激活元件（Ac）进行定向转座子标签法克隆FAE1。在一条携带与第4号染色体上FAE1位点连锁的Ac的品系中分离出一个不稳定的fae1突变体。共分离和回复分析确定新突变体被Ac标记。通过反向聚合酶链反应克隆了Ac侧翼的DNA片段，并用于从由未成熟角果制成的文库中分离FAE1基因组克隆和一个cDNA克隆。FAE1蛋白的预测氨基酸序列与其他缩合酶（查尔酮合酶、芪合酶和β-酮脂酰-酰基载体蛋白合酶III）的氨基酸序列具有同源性，支持FAE1是一种合酶或缩合酶的结构基因这一观点。正如fae1突变对这些组织脂肪酸组成的影响所预期的那样，FAE1在发育中的种子中表达，但在叶片中不表达。
