(A) Comparison of the exon structure of the human TβRI mRNA with the pseudogene on chromosome 19. A detailed alignment of the pseudogene with exons 2 to 4 and the 3'-UTR is available from the authors upon request. Lines depict the 5'-UTR and 3'-UTR. The repetitive elements AluSX, AluSB and L1Pa13 are encircled. (B) Expression pattern of the TβRI gene in human prostatic cells. Expression of both transcript variants (upper panel, 5-TB1RL/3-TB1RL) and expression of the splice variant TβRIB (lower panel; 5-TB1RL/3-HTB1RL) is demonstrated. (C) Scheme of the TβRI protein (EC, extracellular domain; TM, transmembrane domain; kinase, Ser/Thr kinase domain) with the nucleotide and amino acid sequence of exon 2 and exon 3 (capital letters) and the alternatively spliced exon 3B (lower case letters). Additionally, the partial sequence without the alternatively spliced exon is given below. The sequence of TβRI was not available for canis familiaris. The splice site junctions are indicated by italic letters. Bold letters mark the amino acid and nucleotide exchanges with respect to the human sequence. The accession numbers are given below (hs, homo sapiens; mm, mus musculus; rn, rattus norvegicus; ss, sus scrofa; cf, canis familiaris). Arrows indicate the exon boundaries. Ctrl, control.