Bovine protamine genes contain a single intron. The structures of the two alleles.

In a recent paper, we described the isolation of the first bovine protamine cDNA (BPK59), demonstrating that the gene was autosomal and single copy (Krawetz, S. A., Connor, W., and Dixon, G. H. (1987) DNA 6, 45-57). We have since utilized the BPK59 clone as a probe, to isolate both alleles of the protamine gene from a bovine genomic library constructed in Charon 28. The sequenced alleles are highly homologous and code for identical mRNAs. Unlike the trout protamine genes, the bovine gene is not contiguous as it possesses a single intron. This intron divides the highly variable mammalian carboxyl domain from the conserved protamine basic core. Three tandemly repeated CG-like ("enhancer") sequences upstream from the CAAT box have been identified, separated by a conserved spacer region. Their possible role in the transcription of this P1 gene is discussed. The bovine genome immediately surrounding (approximately equal to 20 kilobase pairs) the protamine gene has been mapped and reveals that the sequence flanking the 5' segment of the gene is unique, while the sequence flanking the 3' segment is repetitive.