a The pcDNA3-MEK2S219D-GFP and pcDNA3-GFP (manage) plasmids was transfected to COS-1 cells and The gene. Linkage disequilibrium in between SNPs within a gene is taken evaluated the cell numbers by trypan blue assay from 1 to 4 days post-transfection. Journal of Biomedical Science (2015) 22:Page 11 ofMEK2 have not yet been characterized. From a phylogenic analysis, we identified and isolated zebrafish mek1 and mek2 cDNAs. We also isolated the downstream erk1 cDNA to characterize the function of these two MEK proteins. An in vitro experiment showed that both MEK1 and MEK2 were able to phosphorylate downstream ERK1 by causing it to mutate to the constitutive active form. The ERK1 protein is then translocate from nuclei to the cytoplasm. We conclude that zebrafish MEK1 and MEK2 could activate downstream gene expression through Erk1 phosphorylation. The role of MEK2 in skin tumor development is still being debated. MEK2 functions in mouse melanoma formation but does not contribute to skin tumor formation [17, 26, 27]. Those transgenic mice that contained chemically induced carcinomas or knockout mice were used to characterize the functions of MEK1 and MEK2. The krt14-MEK1 transgenic mice exhibited moderate hyperplasia with spontaneous skin tumor formation at 5 weeks. Downstream signaling is activated by ornithine decarboxylase (ODC) expression . Surprisingly, skin tumors was sporadically formed just within 6 days in our Tg(krt14-MEK2S219D-GFP) transgenic zebrafish. The zebrafish MEK2 was sufficient to induce skin tumor formation through ERK1 activation. In previous reports, the function of MEK1 was important in skin tumor formation. In our results, transient expression of activated MEK1 was produced papillary formation in the epidermis. The skin papilloma was also revealed in activated MEK2 expression. Although we did not establish transgenic zebrafish by expression of activated MEK1, we suggest that MEK1 also potentially to induce skin papilloma formation. Moreover, transient expression of constitutive MEK2 in the epidermis induced papillary formation. These papillae were then excised from the epidermis and placed in the medium. Collection of this skin cells and cultured in L15 medium could be continuously maintained for more than 1 week. Analysis of these skin cells showed intact nuclei, tubulin structure, and cell shape (data not shown). We suggest that these skin cells were experiencing hyper-proliferation due to MEK2 activation. This observation may be relevant to psoriasis but needs further investigation. Ras proto-oncogenes are central regulators activating intracellular Ras-Raf-MEK-ERK signaling pathway in tumorigenesis. PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/25957400 The zebrafish is increasingly made use of as a vertebrate model for studying tumorigenesis and drug screening. A transgenic PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26795252 approach is commonly utilised for Ferent loading places. (C) Longitudinal view of articular cartilage from superficial establishing a transgenic zebrafish. The Tg(fabp10:EGFPkrasv12) trangenic zebrafish especially overexpressed high amount of k.Transgenic zebrafish. The functions of MEK1 and MEK2 inside the Ras/Raf/ Mek/Erk signaling pathway have been well documented. Through epidermal neoplasia formation, MEK2 and MEK1 showed mainly related functions, but each and every had a number of differences. In zebrafish, the functions of MEK1 andFig. six Effect of MEK2S219D on cell proliferation was analyzed in COS-1 cells and in transgenic zebrafish. a The pcDNA3-MEK2S219D-GFP and pcDNA3-GFP (control) plasmids was transfected to COS-1 cells and evaluated the cell numbers by trypan blue assay from 1 to four days post-transfection.