CDKN1A codes for the protein p21, a potent cyclin-dependent kinase (CDK) inhibitor that regulates the cell cycle. The CDKN1A Promoter luciferase reporter vector is designed for studying the regulation of CDKN1A. The vector contains the CDKN1A promoter region upstream of a firefly luciferase reporter gene, which can specifically report activity for CDKN1A activity.