The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling pathway is associated with the innate immune system and plays crucial roles in the mediation of immune response to viral infections. In this study, three STAT isoform cDNAs were cloned from the red swamp crayfish Procambarus clarkii, and they were designated as PcSTATa, PcSTATb, and PcSTATc. PcSTATa and PcSTATb were generated through the alternative splicing of the last exon, and PcSTATc was produced by intron retention. PcSTATa, PcSTATb, and PcSTATc contained 2382, 2337, and 2274 bp open reading frames encoding proteins with 793, 778, and 757 amino acid residues, respectively. Domain prediction analysis revealed that three isoforms of PcSTATs contain a STAT interaction domain, a STAT all-alpha domain, a STAT DNA binding domain, and a Src-homology 2 domain. The mRNA transcripts of three PcSTAT isoforms were detected in all examined tissues of male and female crayfish. The expression levels of the three PcSTAT isoforms in the hemocytes, gills, and intestines significantly changed after the white spot syndrome virus (WSSV) challenge. PcSTAT silencing by dsRNA interference could positively regulate the expression levels of three anti-lipopolysaccharide factors (PcALF1, PcALF2, and PcALF6) and two crustins (PcCrus1 and PcCrus2) and negatively regulate the expression levels of three ALFs (PcALF3, PcALF4, and PcALF5) and two crustins (PcCrus3 and PcCrus4). These results suggest that all three PcSTAT isoforms are involved in the host defense against WSSV infection.

Janus 激酶 (JAK)/信号转导和转录激活剂 (STAT) 信号通路与先天免疫系统相关，并在介导对病毒感染的免疫反应中发挥关键作用。在这项研究中，从红沼泽小龙虾Procambarus clarkii中克隆了三个STAT亚型 cDNA ，并将它们命名为PcSTATa、PcSTATb和PcSTATc。PcSTATa和PcSTATb是通过最后一个外显子的可变剪接产生的，而PcSTATc是通过内含子保留产生的。PcSTATa、PcSTATb和PcSTATc含有 2382、2337 和 2274 bp 的开放阅读框，分别编码具有 793、778 和 757 个氨基酸残基的蛋白质。域预测分析显示 PcSTAT 的三种同工型包含一个 STAT 相互作用域、一个 STAT 全α 域、一个 STAT DNA 结合域和一个 Src 同源 2 域。在雄性和雌性小龙虾的所有检查组织中检测到三种PcSTAT同种型的 mRNA 转录本。白斑综合征病毒 (WSSV) 攻击后，血细胞、鳃和肠中三种PcSTAT亚型的表达水平发生显着变化。通过 dsRNA 干扰PcSTAT沉默可以正向调节三种抗脂多糖因子（PcALF1、PcALF2和PcALF6）和两种结皮蛋白（PcCrus1和PcCrus2）并负调节三种 ALF（PcALF3、PcALF4和PcALF5）和两种结皮蛋白（PcCrus3和PcCrus4）的表达水平。这些结果表明所有三种PcSTAT亚型都参与了宿主对 WSSV 感染的防御。