Analysis of the mechanisms that regulate the AURKB gene

Abstract Background The AURKB gene encodes aurora kinase B ( AURKB ), which acts as a key regulator of mitosis. Aurora kinase B is overexpressed in many cancers at both the protein and mRNA levels; overexpression is associated with metastasis. This study aimed to find novel regulators of AURKB transcription. Methods A bioinformatic approach was used to identify consensus factor binding sites in the AURKB promoter. An AURKB promoter-luciferase construct was generated containing the human AURKB promoter. Cotransfection of this construct with expression plasmids and analysis of transactivation was used to determine whether overexpression of factors identified by conservation and motif analysis had any functional effect on AURKB promoter activity in human 293T cells. Chromatin immunoprecipitation using chromatin from mouse resting B cells and electromobility shift assays using extracts from A549 cells, a human lung cancer cell line, were used to confirm DNA binding Findings The AURKB promoter contained a consensus-binding site for early growth response protein 1 (EGR1). Chromatin immunoprecipitation showed that EGR1 binds to the AURKB promoter in mouse resting B cells. The electromobility shift assay demostrated binding of EGR1 to the consensus binding site in the human AURKB promoter. The identity of the bound protein was confirmed by antibody supershift. Transactivation assays showed an increase in AURKB promoter activity when EGR1 was overexpressed. Interpretation EGR1 might be involved in regulating the expression of AURKB . Abnormal AURKB activity results in disruption of the normally tightly regulated process of cell division, and inhibitors of AURKB are being tested in clinical trials. Therefore an understanding of the regulation of AURKB and identification of factors that might affect its dysregulation in cancer could expedite the therapeutic potential of targeting aurora kinase B. Funding Medical Research Council, National Institute for Health Research Imperial Biomedical Research Centre.