Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Dev Comp Immunol. 2013 Oct;41(2):110-9. doi: 10.1016/j.dci.2013.04.022. Epub 2013 May 6.
Serpin or serine proteinase inhibitor is a family of protease inhibitors that are involved in controlling the proteolytic cascade in various biological processes. In shrimp, several serpins have been identified but only a few have been characterized. Herein, the PmSERPIN3 gene identified from Penaeus monodon EST database was studied. By using the 5'- and 3'-Rapid Amplification of cDNA Ends (RACE) techniques, the full-length of PmSERPIN3 cDNA was obtained. The cDNA contained an open reading frame of 1233 bp encoding for 410 amino acid residue protein. Genome sequence analysis revealed that the PmSERPIN3 was an intronless gene. RT-PCR analysis revealed that it was constitutively expressed in all developmental stages, all shrimp tissues tested, and upon pathogen infections. The recombinant mature PmSERPIN3 protein (rPmSERPIN3) produced in Escherichia coli exhibited inhibitory activity against subtilisin. The rPmSERPIN3 also inhibited the shrimp prophenoloxidase system activation in vitro. Injecting the rPmSERPIN3 along with Vibrio harveyi into the shrimp decreased the clearance rate of bacteria in the hemolymph. Potentially, the PmSERPIN3 functions as a regulator of the proPO activating system.
丝氨酸蛋白酶抑制剂（Serpin）家族是一类参与调控多种生物过程中蛋白水解级联反应的蛋白酶抑制剂。在虾类中，已经鉴定出多种丝氨酸蛋白酶抑制剂，但仅有少数得到了深入研究。本研究从斑节对虾 EST 数据库中鉴定了 PmSERPIN3 基因。利用 5' 和 3' 快速扩增 cDNA 末端（RACE）技术，获得了 PmSERPIN3 cDNA 的全长序列。该 cDNA 含有一个 1233bp 的开放阅读框，编码 410 个氨基酸残基的蛋白质。基因组序列分析表明，PmSERPIN3 是一个无内含子的基因。RT-PCR 分析表明，它在所有发育阶段、所有检测的虾组织以及受到病原体感染时均持续表达。在大肠杆菌中表达的重组成熟 PmSERPIN3 蛋白（rPmSERPIN3）对枯草杆菌蛋白酶具有抑制活性。rPmSERPIN3 还能抑制虾原酚氧化酶系统的体外激活。将 rPmSERPIN3 与哈维弧菌一起注入虾体内，可降低血淋巴中细菌的清除率。因此，PmSERPIN3 可能作为前酚氧化酶激活系统的调节剂发挥作用。
