Schematic representation of the human EPCR gene. The upper diagram shows the overall intron/exon structure of the gene, which consists of four exons (I to IV) and three introns (a to c). Black regions represent the coding regions; white regions represent the 5′ and 3′ untranslated regions to the left and right, respectively. The scale of this diagram is given below the gene. The double headed arrows in the centre represent fragments of the EPCR gene that were amplified from various templates by PCR. Fragment 3/4 resulted from amplification using primers EPCR-3 and EPCR-4; 5/8 resulted from amplification of EPCR-5 and EPCR-8 (Table 1). These primer pairs were exon-specific. Fragments 1A/1B, 2C/2B, 3A/3B, and 4A/4B were amplified using primer pairs EP1A and EP1B, EP2C and EP2B, EP3A and EP3B, and EP4A and EP4B (Table 1). Use of these primers resulted in the amplification of each exon and its associated intron/exon boundaries. The lower diagram represents the EPCR polypeptide. The position of the introns within the amino acid sequence are represented by dotted lines. The residue number is indicated above the position of each intron. The signal peptide, extracellular regions, transmembrane domain, and cytoplasmic tail are also indicated.