Activating transcription factor 2 (ATF2), a member of the bZIP transcription factor family, is involved in multiple physiological and developmental processes, yet its role in the innate immunity remains unclear. In this study, two isoforms (named as MnATF2a and MnATF2b) of ATF2 gene were identified in Macrobrachium nipponense and were produced by exon skipping. The full length of MnATF2a is 2328 bp with an open reading frame of 2079 bp that encode 692 amino acids. MnATF2a has 237 bp nucleotides more than MnATF2b and the extra 237 bp is a complete exon. MnATF2a and MnATF2b proteins contain the same conserved and typical bZIP domain at the C-terminus. MnATF2a has 79 amino acids more than MnATF2b. MnATF2a and MnATF2b are widely distributed in a variety of immune tissues. After Vibrio parahaemolyticus and Staphylococcus aureus infection, the expression levels of MnATF2a and MnATF2b were significant up-regulated in the gills and stomach at 12 h. RNA interference analysis showed that knockdown of the total MnATF2 gene significantly inhibits the transcription of tumor necrosis factor (TNF) and promotes the expression of crustins (including Cru3, Cru4, and Cru7). Further study showed that knockdown of MnTNF evidently increase the expression of Cru3, Cru4, and Cru7. Our research indicates that ATF2 negatively regulate the expression of AMPs by regulating the transcription of TNF in M. nipponense. This study provides valuable information about the function of ATF2 family in the innate immunity in crustacean.

激活转录因子2（ATF2）是bZIP转录因子家族的成员，参与多个生理和发育过程，但其在先天免疫中的作用仍不清楚。在这项研究中，在日本沼虾（Macrobrachium nipponense）中鉴定出ATF2基因的两个同工型（分别命名为MnATF2a和MnATF2b），并通过外显子跳跃产生。MnATF2a的全长为2328 bp，开放阅读框为2079 bp，编码692个氨基酸。MnATF2a比MnATF2b多237 bp核苷酸额外的237 bp是完整的外显子。MnATF2a和MnATF2b蛋白在C端包含相同的保守和典型bZIP结构域。MnATF2a比MnATF2b具有79个氨基酸。MnATF2a和MnATF2b广泛分布在各种免疫组织中。后副溶血性弧菌和金黄色葡萄球菌感染，的表达水平MnATF2a和MnATF2b均显著在鳃和胃12h时上调。RNA干扰分析表明，敲低总MnATF2基因可显着抑制肿瘤坏死因子（TNF）的转录，并促进结缔组织（包括Cru3，Cru4和Cru7）。进一步的研究表明，敲低MnTNF明显增加了Cru3，Cru4和Cru7的表达。我们的研究表明ATF2负的表达调节抗菌肽通过调节的转录的TNF在日本沼虾。这项研究提供了有关ATF2家族在甲壳类动物先天免疫中的功能的有价值的信息。