College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou, 311300, China.
Fish Shellfish Immunol. 2018 Dec;83:104-114. doi: 10.1016/j.fsi.2018.09.028. Epub 2018 Sep 8.
The minichromosome maintenance protein (MCM7) is a member of the MCM protein family which participates in the MCM complex by playing a role in the cell replication cycle and chromosome initiation in eukaryotes. The 2270 bp cDNA sequence of MCM7, including a 2127-bp open reading frame (ORF) encoding a 709-aa protein, was cloned from Scylla paramamosain using RT-PCR and RACE. Data showed that MCM7 was highly expressed in the digestive organ and hepatopancreas of S. paramamosain. Furthermore, MCM7 expression was down-regulated by infection with white spot syndrome virus (WSSV) or Vibrio alginolyticus. When MCM7 was knocked down, immune genes such as Janus kinase (JAK) and crustin antimicrobial peptide (CAP) were down-regulated, and C-type-lectin (CTL) was up-regulated in hemocytes. The mortality of WSSV-infected or V. alginolyticus-infected crabs was enhanced following MCM7 knockdown. It was demonstrated that MCM7 is very important in the progression of WSSV and V. alginolyticus infection. We also investigated the effect of MCM7 on apoptosis rate and phagocytic rate in S. paramamosain. MCM7 knockdown caused higher levels of apoptosis in the hemocytes of the control, WSSV, and V. alginolyticus groups. MCM7 knockdown influenced the activity of phenoloxidase (PO) and superoxide dismutase (SOD), and total hemocyte count (THC) after infection with WSSV or V. alginolyticus, which indicated that MCM7 plays a regulatory role in innate immunity of crabs. Thus, we conclude that MCM7 may participate in the anti-WSSV and V. alginolyticus immune response in crabs by regulating apoptosis and the activity of PO and SOD.
微小染色体维持蛋白（MCM7）是 MCM 蛋白家族的一员，它在真核生物的细胞复制周期和染色体起始中发挥作用，参与 MCM 复合物。使用 RT-PCR 和 RACE，从锯缘青蟹中克隆出 MCM7 的 2270bp cDNA 序列，包括一个编码 709 个氨基酸的 2127bp 开放阅读框（ORF）。数据显示，MCM7 在锯缘青蟹的消化器官和肝胰腺中高度表达。此外，MCM7 的表达在感染白斑综合征病毒（WSSV）或溶藻弧菌后下调。当 MCM7 被敲低时，血细胞中的免疫基因如 Janus 激酶（JAK）和抗菌肽（CAP）下调，C 型凝集素（CTL）上调。在敲低 MCM7 后，WSSV 或 V. alginolyticus 感染的蟹的死亡率增加。结果表明，MCM7 在 WSSV 和 V. alginolyticus 感染的进展中非常重要。我们还研究了 MCM7 对锯缘青蟹凋亡率和吞噬率的影响。MCM7 敲低导致对照组、WSSV 和 V. alginolyticus 组血细胞凋亡水平升高。MCM7 敲低影响了感染 WSSV 或 V. alginolyticus 后酚氧化酶（PO）和超氧化物歧化酶（SOD）的活性以及总血细胞计数（THC），这表明 MCM7 在螃蟹的先天免疫中起调节作用。因此，我们得出结论，MCM7 可能通过调节凋亡和 PO 和 SOD 的活性参与螃蟹的抗 WSSV 和 V. alginolyticus 免疫反应。
