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. The possible domain organization of the proteins encoded by the splice variants (number of Ig domains) is indicated in the right margin. Sequence determination of the CEACAM28 PCR products revealed simultaneous detection of CEACAM28 and CEACAM30 cDNAs (till then unknown). C, CEACAM.