Cloning and sequencing of baboon and cynomolgus monkey intra-acrosomal protein SP-10: homology with human SP-10 and a mouse sperm antigen (MSA-63).

In this study, cDNAs encoding the intraacrosomal protein SP-10 were cloned and sequenced from baboon (Papio papio) and macaque (Macaca fascicularis) testis libraries and the sequence compared to that of human SP-10. Two alternatively spliced SP-10 cDNAs were obtained from both baboon and macaque testis libraries. The two cDNAs in each species contained open reading frames encoding proteins of exactly 285 and 251 amino acids. A 98% homology between baboon and macaque SP-10 was found at the protein and DNA levels. An 85% and 89% homology between baboon and macaque SP-10 and human SP-10 was present at the protein and DNA level, respectively. A mouse intraacrosomal protein, MSA-63, considered to be an SP-10 homologue, exhibited an overall 53% homology to nonhuman primate SP-10 and a 60% homology to human SP-10 at the protein level. Polymerase chain reaction analysis of testis mRNA confirmed the existence of two alternatively spliced SP-10 mRNAs in both nonhuman primates. Primer extension analysis indicated a common major transcriptional start site in baboon, macaque, and human SP-10 67 nucleotides 5' to the ATG codon. The amino acid sequence data for nonhuman primate SP-10s suggest that antibodies generated by vaccinating baboons and macaques with human SP-10 will likely recognize nonhuman primate SP-10, supporting the testing of an SP-10 contraceptive vaccine based on human SP-10 in these nonhuman primate models.