Abstract：
As is well known, apoptosis is an important form of immune response and immune regulation, particularly playing a crucial role in combating microbial infections. Apoptosis-inducing factor 1 (AIF-1) is essential for apoptosis to induce chromatin condensation and DNA fragmentation via a caspase-independent pathway. The nuclear translocation of AIF-1 is a key step in apoptosis but the molecular mechanism is still unclear. In this study, the homologous gene of AIF-1, named AjAIF-1, was cloned and identified in Apostichopus japonicus. The mRNA expression of AjAIF-1 was significantly increased by 46.63-fold after Vibrio splendidus challenge. Silencing of AjAIF-1 was found to significantly inhibit coelomocyte apoptosis because the apoptosis rate of coelomocyte decreased by 0.62-fold lower compared with the control group. AjAIF-1 was able to promote coelomocyte apoptosis through nuclear translocation under the V. splendidus challenge. Moreover, AjAIF-1 and Ajimportin β were mainly co-localized around the nucleus in vivo and silencing Ajimportin β significantly inhibited the nuclear translocation of AjAIF-1 and suppressed coelomocyte apoptosis by 0.64-fold compared with control. In summary, nuclear translocation of AjAIF-1 will likely mediate coelomocyte apoptosis through an importin β-dependent pathway in sea cucumber.
摘要：
众所周知,细胞凋亡是免疫应答和免疫调节的重要形式,特别是在对抗微生物感染方面发挥关键作用。凋亡诱导因子1（AIF-1）对于通过不依赖半胱天冬酶的途径诱导染色质凝聚和DNA片段的凋亡至关重要。AIF-1的核转位是细胞凋亡的关键步骤，但其分子机制尚不清楚。在这项研究中,在刺参中克隆并鉴定了AIF-1的同源基因，命名为AjAIF-1。脾弧菌攻击后，AjAIF-1的mRNA表达显着增加了46.63倍。发现沉默AjAIF-1可显着抑制腔体细胞凋亡，因为腔体细胞的凋亡率比对照组降低了0.62倍。AjAIF-1能够在脾弧菌攻击下通过核易位促进腔体细胞凋亡。此外，AjAIF-1和Ajimportinβ在体内主要共定位在细胞核周围，沉默Ajimportinβ可显着抑制AjAIF-1的核转位，并抑制腔体细胞凋亡，是对照组的0.64倍。总之,AjAIF-1的核易位可能会通过输入蛋白β依赖性途径介导海参的腔体细胞凋亡。
