Transcriptional Regulatory Sequences of Carcinoembryonic Antigen: Identification and Use with Cytosine Deaminase for Tumor-Specific Gene Therapy

ABSTRACT The 5′ sequences from the human carcinoembryonic antigen gene (CEA) were analyzed using luciferase reporter gene assays. This analysis identified important cis-acting sequences needed for selective expression in CEA-positive cells. Over 50 CEA/luciferase reporter clones were constructed and analyzed in two CEA-positive and two CEA-negative cell lines. The CEA sequences analyzed extended from the translational start to 14.5 kb 5′ of the CEA gene. A 408-bp region from the CEA 3′ untranslated region was also examined for its effect on reporter gene activity. The CEA promoter was located between bases –90 and +69 of the transcriptional start site. Sequences between –41 and –18 were essential for expression from the CEA promoter. Multimerization of sequences between –89 and –40 resulted in copy number-related increases in both expression level and selectivity for CEA-positive cells. Two upstream regions of CEA, –13.6 to –10.7 kb or –6.1 to –4.0 kb, when linked to the multimerized promoter led to high-...