Figure 2.

Coexpression of the two different bovine PrP 5′ UTR exons in 17 different tissues. RNA fractions were subjected to reverse transcription–PCR using primers specific to exon 1a and exon 3. The PCR products were analyzed by Southern blot hybridization with a ³²P-labeled oligonucleotide specific for exon 1a (A and B). The hybridization revealed two fragments (250 and 350 bp). Hybridization with a ³²P-labeled oligonucleotide specific for exons 3 or 2 gave identical results. Hybridization with an exon 1b-specific oligonucleotide revealed only the 350-bp fragment, as shown for brain and spleen (C). All tissues tested gave identical results (data not shown). Lu, lung; Br, brain; Ce, cerebellum; Ad, adrenal gland; Mu, skeletal muscle; He, heart; To, tonsil; Sp, spleen; Re, retina; On, optic nerve; Ln, lymph node; In, intestine; Sk, skin; Th, thymus; Me, mesentery; Li, liver; Ki, kidney. A and B differ by the autoradiography exposure conditions, 2 h at room temperature or at −80°C, respectively. Autoradiography in C was exposed overnight at −80°C.