Carcinin, a member of the crustin family, plays important roles in crustacean innate immunity. In this study, we identified two carcinin isoforms (MnCarc1 and MnCarc2) produced by alternative splicing from Macrobrachium nipponense. The full length of MnCarc1 and MnCarc2 cDNA are 1554 and 1495 bp with 687 and 609 bp open reading frame-encoding proteins that contain 228 and 202 amino acids, respectively. The genome of carcinin has nine exons and eight introns. MnCarc1 transcript contains all nine exons, whereas MnCarc2 only contains eight exons and lacks exon 4. MnCarc1 and MnCarc2 proteins contain a signal peptide, cysteine-rich regions, and a whey acidic protein domain. The phylogenetic tree shows that MnCarc1 and MnCarc2 are not grouped with other crustins and carcinins. MnCarc1 and MnCarc2 form a subgroup. MnCarc1 and MnCarc2 are widely distributed in various tissues. The expression of MnCarc1 and MnCarc2 were evidently upregulated at multiple time points in hemocytes and the intestine of M. nipponense after white spot syndrome virus, Vibrio parahaemolyticus, and Staphylococcus aureus challenges. Further studies showed that knockdown of MnDorsal or MnStat transcription factor could remarkably inhibit the upregulated expression of MnCarc1 and MnCarc2 caused by viral or bacterial challenges. In addition, recombinant MnCarc1 and MnCarc2 proteins could bind to various bacteria and polysaccharides and inhibit the growth of S. aureus and V. parahaemolyticus in vitro. This study indicated that carcinins from M. nipponense were involved in prawns innate immunity.

Carcinin是Crustin家族的成员，在甲壳动物的先天免疫中起着重要作用。在这项研究中，我们确定了两种沼虾同工型（MnCarc1和MnCarc2），它们是通过日本沼虾的选择性剪接产生的。MnCarc1和MnCarc2 cDNA的全长分别为1554和1495 bp，带有687和609 bp的开放阅读框编码蛋白，分别包含228和202个氨基酸。癌蛋白的基因组有9个外显子和8个内含子。MnCarc1转录本包含所有九个外显子，而MnCarc2仅包含八个外显子，而缺少外显子4。MnCarc1和MnCarc2蛋白包含信号肽，富含半胱氨酸的区域和乳清酸性蛋白结构域。系统发育树表明，MnCarc1和MnCarc2没有与其他硬蛋白和癌蛋白结合。MnCarc1和MnCarc2形成一个亚组。MnCarc1和MnCarc2广泛分布在各种组织中。的表达MnCarc1和MnCarc2在血细胞的多个时间点明显上调和肠道日本沼虾后白斑综合症病毒，副溶血性弧菌，和金黄色葡萄球菌的挑战。进一步的研究表明MnDorsal的敲低或MnStat转录因子可显着抑制病毒或细菌攻击引起的MnCarc1和MnCarc2表达上调。此外，重组MnCarc1和MnCarc2蛋白可以与各种细菌和多糖结合，并在体外抑制金黄色葡萄球菌和副溶血弧菌的生长。这项研究表明，从carcinins日本沼虾都参与了对虾先天免疫。