Bac4 is a bovine cathelicidin gene contiguous to another member of this family named Bac7. Although mutations in the sequence suggested that Bac4 gene might be non-functional, primers based on Bac4 specific sequences allowed amplification of a 900 bp cDNA. The transcript comprises the sequences of exons 1, 2 and 3 of Bac7, and of exons 2, 3 and 4 of Bac4 gene and may result from a weak termination control of the transcription of the upstream Bac7 gene.