Background: One of the pathological hallmarks of Alzheimer's disease is the presence of fibrillary amyloid-β deposits, which result from cleavage of the amyloid precursor protein. Understanding the regulatory mechanism of the amyloid precursor protein gene expression is crucial for comprehending the genesis and development of Alzheimer's disease. The nucleic acid binding protein, Purα, is best characterized as a transcriptional factor (TF) with affinity to singlestrand G/C-rich regions. In a previous study, we demonstrated that the Purα protein can downregulate amyloid precursor protein (APP) promoter activity, but the mechanism underlying this downregulation requires further investigation. To better understand this mechanism, we analyzed the characteristic of the APP promoter and found that another transcriptional factor, namely Egr-1, can bind the APP promoter and may exert transcriptional regulatory effects on APP gene expression. Therefore, the interaction between these two transcriptional factors may explain the mechanism in regulating APP gene expression.