凡纳滨对虾(Litopenaeus vannamei)Runt转录因子的基因克隆及其功能分析

MOLECULAR CLONING OF RUNT GENE AND EXPRESSION IN LITOPENAEUS VANNAMEI

Runt结构域转录因子家族(Runx)在哺乳动物体内存在三种基因型,分别起着造血,骨生成和控制上皮细胞增殖的作用。本文应用反转录和c DNA末端快速扩增(RACE)技术,首次在凡纳滨对虾(Litopenaeus vannamei)中克隆并测序了一种Runt(lvrunt)基因全长。lvrunt c DNA全长1754bp,含有1个663bp长的开放阅读框,编码221个氨基酸,理论分子量为23.6k Da,具有Runt-family结构域。对凡纳滨对虾鳃、肠、肝胰腺、类淋巴、心脏、肌肉组织和血淋巴lvrunt的转录特征进行分析,结果显示该基因几乎特异性地在血淋巴细胞中表达,而在其他组织中表达较低。肌肉注射重组造血激素蛋白(r AST)或白斑综合征病毒(WSSV)粗提液均可显著提高lvrunt在凡纳滨对虾体内的转录表达。上述结果提示,lvrunt主要在血细胞发挥作用,可能作为造血激素的下游基因起到调节血细胞增殖和分化的作用,并在受到病毒感染后,参与提升血细胞数量或者促进血细胞分化的过程。

There are three runt-related(Runx) transcription factors in mammals that involved in hematopoiesis, osteogenesis, and cell proliferation and differentiation. We report the c DNA cloning of the full runt gene of Litopenaeus vannamei(lvrunt) by rapid amplification of c DNA ends(RACE) PCR. The full-length gene was 1754 bp with a 663 bp ORF, encoding 221 amino acids with the calculated molecular mass of 23.6k Da. The deduced amino acid sequence contained a runt-family domain. To investigate the function of lvrunt, we then studied its gene transcription level in seven tissues of the shrimp. In comparison, the transcription of lvrunt was found in hemocytes mostly but rarely in other tissues. In addition, the expression level of lvrunt m RNA significantly increased in hemocytes by recombined astakine protein or WSSV injection. Therefore, lvrunt probably acts as a downstream gene of astakine, playing a role in regulating hemocytes proliferation and differentiation in nonspecific immunity process.