Chicken protamine genes are intronless. The complete genomic sequence and organization of the two loci

Abstract

A positive cosmid clone obtained from a pwe15-rooster DNA library using a chicken protamine cDNA probe reveals the complete sequence of the two loci for the rooster protamine genes. The organization of these two loci within the cosmid clone matches that of genomic DNA. The copy number per haploid genome is two. The sequence for the rooster protamine predicted from the coding region shows differences from that previously determined at the protein level (Nakano, M., Tobita, T., and Ando, T. (1976) Int. J. Peptide Protein Res. 8, 565-578). A recent re-determination of the rooster protamine amino acid sequence (28 residues from the N terminus) matches that predicted from the genome rather than the sequence of Nakano et al. (1976). Both loci are intronless and the gene is extremely GC-rich (88% in the coding region). The 5' region of the gene contains a typical TATAAA box, several CG boxes, as well as other characteristic motifs. The 3' region of the gene contains the polyadenylation signal and several GT repeats of known Z-DNA forming potential. A correlation between the functional map of the gene and the tendency of the DNA to bend or to adopt the Z-conformation is presented and possible roles for these conformations in the transcription of this gene are discussed.