(A). Expression of transthyretin in CPEC cells at the transcript level. Total mRNA was isolated from sheep 4 V whole CP, EECF and CPEC in primary culture at 48 h, 72 h and 8d after seeding. The 436-bp-long and 332-bp-long fragments amplified using oligonucleotides specific for transthyretin and GAPDH, respectively, were visible in samples from both fresh tissue and cellular cultures at various periods after seeding. From these gels the expression of TTR was estimated relative to GAPDH and the values presented in the bar graphs. They show that TTR mRNA expression is similar to that of fresh tissue in 8d-old cultured cells. Sheep liver and heart homogenate were processed in parallel as positive and negative controls, respectively (not shown). Far left lane contains DNA molecular weight markers. (B) Expression of transthyretin in 8d-old monolayers of CPEC cells at the protein level. CPEC were treated with goat anti-transthyretin polyclonal IgG (1:400) and then with mouse anti-goat IgG. There was intensive fluorescence in the cytoplasm, while the nuclei were not stained. Scale bar 10 μm.