Analysis of the CD46 and CD46-TV transcripts. (A) Diagram of CD46 structure. The CD46 protein contains four short consensus repeats (SCRs), and a serine, threonine and proline-rich (STP) region that is followed by a short region of unknown function, a transmembrane domain (TM) and a cytoplasmic domain (cyt). The arrow indicates the signaling path after accepting the ligand. (B) Comparison of the bovine and porcine CD46 amino acid sequences. The bovine CD46 amino acid sequence (NCBI: NP_001229490.1) was aligned to the porcine sequence (NCBI: NP_999053.1) by BLAST. Identical amino acid residues within the two species are indicated in grey. The positions of the SCRs, STP, TM and CT (cyt) domains corresponding to different amino acids are shown above the sequences. Amino acids of the CD46-TV retention transcript in comparison to the porcine CD46 are bolded.