We recently cloned members of the murine carcinoembryonic antigen (CEA) gene family, some of which are differentially expressed during placental development. By intra- and interspecies sequence comparisons, we identified an element in the putative promoter and/or 5′-nontranslated region which is conserved within all human and rodent CEA-related genes analyzed so far. Using gel retardation analysis and DNasel hypersensitive site mapping, we now show that ubiquitously expressed nuclear factors specifically bind to the conserved region derived from the mouse gene Cea-2 in vitro and probably also in vivo. Another DNasel hypersensitive site lies within or close to a simple sequence motif [(GGA)n] located in the first intron of Cea-2. Such sequences have been reported to play a role in the regulation of certain genes. Therefore, this analysis has identified putative regulatory regions for Cea-2 and possibly CEA-related genes in general.