达氏鲟Elovl4、ELovl5和Elovl7克隆、组织分布及饥饿对其表达的影响

MOLECULAR CLONING,TISSUE DISTRIBUTION OF ELOVL4,ELOVL5 AND ELOVL7 FROM ACIPENSER DABRYANUS

为研究长链脂肪酸延长酶(Elovls)作用机制,实验根据前期达氏鲟转录组测序获得的unigene序列为基础,得到Elovl4、Elovl5和Elovl7 CDS区序列,并分析了3个基因在各组织及饥饿胁迫下的表达情况。结果显示,达氏鲟Elovl4、Elovl5和Elovl7编码区为753、885和846 bp,分别编码250、294和281个氨基酸。达氏鲟Elovl4、Elovl5和Elovl7氨基酸序列与斑点雀鳝Elovls具有较高的同源性;组织分布结果显示,达氏鲟Elovl4在卵巢和眼中表达最高;Elovl5在肌肉中的表达显著高于其他各个组织;Elovl7在卵巢中表达最高(P<0.05),鳃、精巢和肌肉中表达较多。在饥饿条件下,Elovl4、Elovl5和Elovl7在肝脏中的表达量均显著下调(P<0.05),肠道中的趋势各有不同;饥饿3d时,Elovl4、Elovl5和Elovl7在胃中的表达量显著降低,随后上调(P<0.05);饥饿7d时,脑和肌肉中Elovl4、Elovl5和Elovl7的表达量显著高于其他各组,随后显著下降(P<0.05)。这说明Elovl4、Elovl5和Elovl7在达氏鲟营养调控过程中发挥的作用可能存在差异,其具体作用机制需要进一步研究。

Long-chain polyunsaturated fatty acids(LC-PUFAs)are essential for numerous critical biological processes,and elongases of very long chain fatty acids are the rate-limiting enzyme for LC-PUFAs synthesis.The CDS of Elovl4,Elovl5 and Elovl7 were cloned from the unigene database by full-length transcriptome sequencing of A.dabryanus.Results showed that the open reading frames(ORF)of Elovl4,Elovl5 and Elovl7 were 753,885 and 846 bp which encoded 250,294 and 281-residue peptide,respectively.Phylogenetic analysis showed that the Elovl4,Elovl5 and Elovl7 clustered with Lepisosteus oculatus.Tissue expression analysis showed that the highest Elovl4 level was in the ovary and eye;muscle Elovl5 level was significantly higher than other tissues and the highest Elovl7 was in ovary,which was followed by gill and testis(P<0.05).Starvation significantly decreased the expression of liver Elovl4,Elovl5 and Elovl7(P<0.05).Stomach Elovl4,Elovl5 and Elovl7 reduced significantly(P<0.05)at day 3,and then significantly upregulated.The highest expression levels of Elovl4,Elovl5 and Elovl7 in brain and muscle were at day 7,and then dropped dramatically(P<0.05).These findings suggest that Elovl4,Elovl5 and Elovl7 may play certain roles in the nutritional regulation of A.dabryanus,and the specific mechanisms need further investigation.