Expression pattern of dog CEACAM1-related genes Figure 7 Expression pattern of dog CEACAM1-related genes. CEACAM1-related transcripts were identified by RT-PCR using gene-specific primers which are located in the N domain and transmembrane exons. For the detection of CEACAM1 transcripts, primers in the N domain and cytoplasmic domain exon 3 were used. The products were separated by agarose gel electrophoresis in the presence of ethidium bromide and visualized by UV illumination. One-kb and 100-bp DNA fragment ladders were used as markers.