中文摘要：

通过构建仿刺参cDNA文库，获得铁蛋白全长cDNA序列。该基因序列全长792bp，5’-非翻译区长133bp，开放阅读框长522bp，编码173个氨基酸，3’-UTR长137bp；预测蛋白分子量为20ku。5’-UTR具有一个高度保守的铁离子应答元件。仿刺参ferritin氨基酸序列具备脊椎动物ferritin的亚铁氧化酶活性中心所特有的保守结构。该序列与海参的同源性最高，达84％，与其它无脊椎动物如：海星、鲍、牡蛎、海葵、线虫、小龙虾和果蝇的同源性为74％～34％；与脊椎动物ferritin重链亚基同源性高于轻链亚基。系统进化分析表明，仿刺参的ferritin与大部分无脊椎动物聚为一支。利用半定量RT—PCR检测，ferritin mRNA在仿刺参未受精卵、受精卵、多细胞期、囊胚期、原肠期、小耳状幼体、中耳状幼体、大耳状幼体、樽型幼体、五触手幼体、稚参11个发育阶段和幼参的体壁、体腔细胞、肠道和呼吸树中均表达。Quantitative real—time PCR结果显示，ferritin mRNA在未受精卵至原肠期表达量低，从小耳状幼体至稚参表达量显著增高；在幼参的不同组织中，ferritin mRNA在呼吸树中的表达量显著低于其他3种组织；幼参注射LPS后，4种组织中ferritin mRNA表达量与注射前无显著差异。

英文摘要：

Ferritin is widely distributed throughout the plant and animal kingdoms in a highly conserved conformation,which plays a key role in cellular iron metabolism including iron storage and detoxification. Vertebrate ferritin has been indirectly linked to innate immune response since their synthesis is regulated by proinflammatory cytokines. In invertebrate, ferritin has also been shown to be relevant to innate immune defense via iron-withholding strategy because it can be elevated by LPS challenge. To be better understand the sequences information and do further research on the function of ferritin, the cDNA sequence is characterized and the gene expression pattern is profiled. In this study, a full-length ferritin cDNA sequence was obtained by constructing cDNA libraries of sea cucumber（Apostichopus japonicus）, which was 792 bp long, and includes a 133 bp long 5＇-untranslated region（UTR）,0RF encoding 173 amino acids,and a 137 bp long 3＇-UTR; the molecular weight predicted was 20 ku. The 5＇-UTR contains a highly conserved iron responsive element（IRE） sequence. The amino acids have a conserved motif for ferroxidase center typical of heavy chains of vertebrate ferritins. Sequence comparison showed that it reached the highest similarities of 84% with sea cucumber Holothuria glaberrima and shared more identity to H-chains of vertebrate ferritins than to the L-chains. It also shared 74% -34% identity with invertebrate ferritins compared with sea star, abalone, oyster, sea anemone, nematode, crayfish and drosophila. Phylogenetic analysis revealed the A. japonicus ferritin was grouped together with the invertebrate ferritin cluster. The ferritin mRNA were identified by using RT-PCR at development stages of sea cucumber including unfertilized egg, fertilized egg, cellulous stages, blastula, gastrnla, early auricularia, auricularia, late auricularia, doliolaria, pentactula, juvenile and in different tissues of young sea cucumbers including intestines, coelomocytes, respiratory trees and body walls. Quantitat