Identification and characterization of c-raf from orange-spotted grouper (Epinephelus coioides)

作者：Mo, Ze-Quan; Lai, Xue-Li; Wang, Wan-Tao; Chen, Hong-Ping; He, Zhi-Chang; Han, Rui; Wang, Jiu-Le; Luo, Xiao-Chun; Li, Yan-Wei^*; Dan, Xue-Ming^*

来源：Fish and Shellfish Immunology, 2020, 96: 311-318.

DOI：10.1016/j.fsi.2019.12.017

• Epinephelus coioides
• Cryptocaryon irritans
• SGIV
• c-Raf

C-Raf proto-oncogene serine/threonine kinase is a mitogen-activated protein kinase (MAP) kinase kinase, which can initiate a mitogen-activated protein kinase (MAPK) cascade by phosphorylating the dual-specific MAP kinase kinases (MEK1/2), and in turn activate the extracellular signal-regulated kinases (ERK1/2). To study the function of c-Raf in teleost fish, a c-Raf cDNA sequence from orange-spotted grouper (Epinephelus coioides) was cloned. Ecc-Raf shared 81%-99% amino acid identity with other vertebrate c-Raf molecules, and shared the highest amino acid identity (99%) with Lams calcarifer c-Raf. Genomic structure analysis revealed that grouper c-Raf shared a conserved exon structure with other vertebrates. Tissue distribution showed that Ecc-Raf was mainly transcribed in systemic immune organs. Ecc-Raf was distributed throughout the cytoplasm of transfected GS cells and the overexpression of Ecc-Raf only slightly enhanced the activation of Activator protein 1. The phosphorylation levels of Ecc-Raf can be induced by PMA and H2O2 treatment, in contrast to DMSO or untreated HKLs. Moreover, the phosphorylation level of the Raf-MEK-ERK axis was downregulated after 24 h of SGIV infection. On the other hand, the total level and phosphorylation level of c-Raf significantly increased post C. irritans infection and showed an enhanced level post immunization. The results of this study suggested that the Raf-MEK-ERK cascade was involved in the response to viral or parasitic infections.

• 单位
  华南农业大学