PmPPAE2, a new class of crustacean prophenoloxidase (proPO)-activating enzyme and its role in PO activation
PmPPAE2, a new class of crustacean prophenoloxidase (proPO)-activating enzyme and its role in PO activation
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DOI：
10.1016/j.dci.2010.09.002
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发表时间：
2011-01-01
影响因子：
2.9
通讯作者：
Tassanakajon, Anchalee
中科院分区：
文献类型：
--
作者：
Charoensapsri, Walaiporn;Amparyup, Piti;Tassanakajon, Anchalee
酚氧化酶原激活系统在无脊椎动物抵御微生物入侵中起着重要作用。在本研究中，我们报道了来自斑节对虾血细胞的第二种前激活酶(命名为PmPPAE2)。PmPPAE2具有Clip结构域丝氨酸蛋白酶家族的结构特征，与昆虫Manduco sexta PAP-1的氨基酸序列具有51%的相似性。与已有的节肢动物PPAE序列的氨基酸序列比对表明，PmPPAE2是一类新的甲壳类PPAE。转录表达分析表明，PmPPAE2转录本主要在血细胞中表达。双链RNA介导的抑制PmPPAE2转录水平导致血淋巴总PO活性显著降低(41%)，并增加了对虾对哈维氏弧菌感染的敏感性。基因组组织分析表明，PmPPAE1和PmPPAE2由不同的基因组位点编码。PmPPAE1基因由10个外显子和9个内含子组成，而PmPPAE2基因由8个外显子和7个内含子组成。对4个关键基因(PmPPAE1、PmPPAE2、PmproPO1和PmproPO2)在幼体发育阶段的表达分析表明，PmPPAE1和PmproPO2在幼体发育的各个阶段(无节幼体、原生动物、Mysis和后期幼体)都有表达，而PmPPAE2和PmproPO1的转录本主要在幼体发育后期(Mysis和后期幼体)表达。这些结果表明，PmPPAE2具有对虾PPAE的功能，可能介导了PmproPO1的激活。(C)2010爱思唯尔有限公司。保留所有权利。
The prophenoloxidase (proPO) activating system plays an important role in the defense against microbial invasion in invertebrates. In the present study, we report a second proPO-activating enzyme (designated PmPPAE2) from the hemocytes of the black tiger shrimp, Penaeus monodon. PmPPAE2 contained the structural features of the clip domain serine proteinase family and exhibited 51% amino acid sequence similarity to the insect Manduco sexta PAP-1. Amino acid sequence alignment with the available arthropod PPAE sequences demonstrated that PmPPAE2 is a new class of crustacean PPAE. Transcript expression analysis revealed that PmPPAE2 transcripts were mainly expressed in hemocytes. Double-stranded RNA-mediated suppression of PmPPAE2 transcript levels resulted in a significant decrease in the total hemolymph PO activity (41%) and also increased the shrimp's susceptibility to Vibrio harveyi infection. Genomic organization analysis revealed that PmPPAE1 and PmPPAE2 are encoded by different genomic loci. The PmPPAE1 gene consists of ten exons and nine introns, whilst PmPPAE2 comprises of eight exons interrupted by seven introns. Analysis of the larval developmental stage expression of the four key genes in the shrimp proPO system (PmPPAE1, PmPPAE2, PmproPO1 and PmproPO2) revealed that PmPPAE1 and PmproPO2 transcripts were expressed in all larval stages (nauplius, protozoea, mysis and post-larvae), whilst PmPPAE2 and PmproPO1 transcripts were mainly presented in the late larval developmental stages (mysis and post-larvae). These results suggest that the PmPPAE2 functions as a shrimp PPAE and possibly mediates the activation of PmproPO1. (C) 2010 Elsevier Ltd. All rights reserved.