Molecular cloning of preproacrosin and analysis of its expression pattern in spermatogenesis

Complementary DNA clones for the boar preproacrosin have been isolated from a randomly primed testis cDNA library in lambda gt10 and from an oligo(dT)-primed testis cDNA in lambda gt11. The nucleotide sequence of the 1418-bp cDNA insert includes a 46-bp 5'-untranslated region, an open reading frame of 1248 bp corresponding to 416 amino acids (45.59 kDa) and a 121-bp 3'-untranslated region. The deduced amino acid sequence includes the active-site residues histidine, asparagine and serine of the catalytic triad of the serine proteinase super-family and is colinear with that determined by amino acid sequencing of the boar acrosin light chain and of a small region of the NH2-terminal sequence of the heavy chain. The preproacrosin cDNA contains at the 3' end a 381-bp sequence which codes for an amino acid sequence not yet found in any other serine proteinase. This amino acid sequence is rich in proline (42 out of 127 amino acids) and is suggested to be involved in the recognition and binding of the spermatozoa to the zona pellucida of the ovum. The mRNA for preproacrosin is synthesized as an approximately 1.6-kb-long molecule only in the postmeiotic stages of boar and bull spermatogenesis.