Ubiquitin specific peptidase 22 regulates the transcription activity of mitogen-activated protein kinase kinase 6 gene

Abstract

To clone human mitogen-activated protein kinase kinase 6 (MKK6) gene promoter and explore its transcription activity by ubiquitin specific peptidase 22 (USP22). Methods: MKK6 gene promoter was amplified by PCR and two bases mutation within USP22 binding site was subsequently introduced. The wild type and mutant MKK6 promoter were inserted into the luciferase report vector pGL3-Basic, respectively. Recombinant plasmids were co-transfected with plasmid pRL-TK into HeLa cells, and the luciferase activities were measured by dual luciferase reporter system. Furthermore, the direct interaction between USP22 and MKK6 promoter was detected by chromatin immunoprecipitation (ChIP) assay. Finally, the MKK6 transcription activity was measured after knockdown of USP22. Results: The recombinant luciferase report vectors containing wild or mutant type of MKK6 promoter were successfully constructed. Mutation of USP22 binding site resulted in decrease of MKK6 promoter-driven luciferase activity in HeLa cells (P<0.05). USP22 could interact directly with MKK6 promoter. Down-regulation of USP22 led to the decreased MKK6 mRNA expression (P<0.05). Conclusion: USP22 could regulate the transcription activity of MKK6 gene in HeLa cells.