Roscoe T J, Lessire R, Puyaubert J, Renard M, Delseny M
Laboraoire de Génome et Développement des Plantes, CNRS UMR 5096, Université de Perpignan, France.
FEBS Lett. 2001 Mar 9;492(1-2):107-11. doi: 10.1016/s0014-5793(01)02243-8.
Low erucic acid rapeseed (LEAR) is characterised by a near absence of very long chain fatty acids in the seed oil which has been correlated with a lack of acyl-CoA elongation activity. Here we show that the absence of acyl-CoA and ATP-dependent elongation activities in microsomes isolated from LEAR embryos is associated with an absence of beta-ketoacyl-CoA synthase activity encoded by the Bn-fatty acid elongation 1 (FAE1) genes. Size exclusion chromatography of solubilised microsomes revealed the presence of a high molecular mass acyl-CoA elongase complex in high erucic acid rapeseed which was absent in microsomes isolated from LEAR seeds. Although transcripts for the Bn-FAE1 genes were detected in LEAR embryos, immunoblots using antisera raised against the beta-ketoacyl-CoA synthase indicated an absence of this protein. Comparison of the deduced amino acid sequences of immature embryo cDNAs reveals that LEAR alleles of Bn-FAE1 encode variant beta-ketoacyl-CoA synthase proteins.
低芥酸菜籽（LEAR）的特征是其种子油中几乎不存在非常长链的脂肪酸，这与缺乏酰基辅酶A延长活性有关。在此我们表明，从LEAR胚胎中分离出的微粒体中缺乏酰基辅酶A和ATP依赖性延长活性，这与由Bn-脂肪酸延长1（FAE1）基因编码的β-酮脂酰辅酶A合酶活性的缺失有关。对溶解的微粒体进行尺寸排阻色谱分析显示，高芥酸菜籽中存在高分子量的酰基辅酶A延长酶复合物，而从LEAR种子中分离出的微粒体中则不存在。尽管在LEAR胚胎中检测到了Bn-FAE1基因的转录本，但使用针对β-酮脂酰辅酶A合酶产生的抗血清进行的免疫印迹表明该蛋白不存在。对未成熟胚cDNA推导的氨基酸序列进行比较发现，Bn-FAE1的LEAR等位基因编码变异的β-酮脂酰辅酶A合酶蛋白。
