PubMed · 1012000
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K L Polakoski, L J Zaneveld. 1976. Proacrosin.. https://doi.org/10.1016/s0076-6879(76)45029-2
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In the present study, molecular cloning, sequencing and restriction mapping of the genomic sequence encoding human proacrosin is described. The full-length cDNA encoding human proacrosin was utilized to recover a 17-kb human genomic clone which was sequenced without further subcloning. The nucleotide sequences of the exons agree with the sequence of the cDNA reported previously. More than 500 bases of the promoter region were sequenced and found to be highly GC rich but devoid of an identifiable TATA box. These findings are generally consistent with a recently published report [Keime, S., Adham, I. M. & Engel, W. (1990) Eur. J. Biochem. 190, 195-200]. However, further sequence analysis revealed discrepancies between our clone and that previously reported. Sequencing of the first intron showed similarity with the published data for 54 bases of the 5' region, beginning with the donor splice site, and for 114 bases at the 3' end. However, 500 bases sequenced distal to the initial 54 bases at the 5' end of intron 1 showed no similarity with the published sequence. In addition, the boundaries of intron 3 differed such that a cytosine residue previously reported to be in exon 3 was found to be the first base of exon 4. Detailed studies were undertaken to confirm that our clone constitutes the authentic sequence of human proacrosin. Cloning and characterization of the human proacrosin gene may allow for informative studies of its regulation, and for a more detailed examination of its role in fertilization.
A testicular protein band has been identified and shown to be immunoreactive to both of the proacrosin (53-55 kd) and the proacrosin binding protein (28 kd) antibodies. pH 4.5 extracts of boar testis were prepared and subjected to Western blot analysis using polyclonal antibodies of the proacrosin and the proacrosin binding protein. In addition to their respective antigens, a distinct high molecular weight protein band of approximately 200 kd was detected by both of the antibodies. Gelatin SDS-PAGE analysis of the extracts showed that this protein band was proteinase active. These results suggest that the proacrosin molecule is present as a much higher molecular weight form in the boar testis than the currently known 53-55 kd forms that have been isolated from spermatozoa.
Trypsin-like inhibitors secreted by the male accessory sex glands have been identified in the seminal plasma of every mammalian species so far investigated. They bind to acceptor molecules on the anterior part of ejaculated sperm, and are thought to play a role in the capacitation of spermatozoa stabilizing zona pellucida binding sites during sperm uterine passage, and then dissociating to allow sperm-egg's zona pellucida interaction. Here we report the identification of acrosin inhibitor acceptor molecules isolated from boar seminal plasma. These proteins, termed AQN-1 and AWN, belong to the recently described spermadhesin protein family, whose members have been implicated in sperm-zona pellucida recognition events. Thus, members of the spermadhesin family, although not possessing detectable enzymatic activity, show features of serine proteinases, and may be involved in both sperm capacitation and sperm-egg recognition and binding events.