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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #170122
Title: UBIQUITIN AS AN OBJECTIVE MARKER OF SEMEN QUALITY AND FERTILITY IN BULLS

Author
item SUTOVSKY, PETER - U OF MO-COLUMBIA
item Geary, Thomas
item BASKA, KATHLEEN - U OF MO-COLUMBIA
item MANANDAHAR, GAURISHANKAR - U OF MO-COLUMBIA
item FENG, DONGYAN - U OF MO-COLUMBIA
item LOVERCAMP, KYLE - U OF MO-COLUMBIA
item SUTOVSKY, MIRIAM - U OF MO-COLUMBIA

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2004
Publication Date: 8/31/2004
Citation: Sutovsky, P., Geary, T.W., Baska, K., Manandahar, G., Feng, D., Lovercamp, K.W., Sutovsky, M. 2004. Ubiquitin as an objective marker of semen quality and fertility in bulls. Proceedings of Nebraska Applied Reproductive Strategies in Beef Cattle p.185-199.

Interpretive Summary: Our and other research indicates that ubiquitin protein is secreted by the epididymal epithelium into epididymal fluid and covalently linked to the surface of defective mammalian spermatozoa. Since many of such spermatozoa can be found in the semen, ubiquitin is a suitable marker of sperm abnormalities. Ubiquitin-based sperm quality assays are relatively easy and not costly to perform and have a number of advantages over other methods of semen evaluation including objectivity, independence from semen handling and storage methods, and universality with regard to recognizing multiple types of obvious and cryptic sperm defects. Further effort will be focused on validation of such assays and their dissemination of artificial insemination and natural breeding programs.

Technical Abstract: Andrology is one of few fields of medicine and biology in which biochemical and molecular tools are not routinely used for sample evaluation. Consequently, it is highly desirable to develop methods for accurate semen analysis and estimation of current fertility and future fertility in large farm animals including bulls, boars, and stallions. Toward this goal, we have been working on the identification of 'negative' sperm quality markers, i.e. proteins associated with morphologically and/or functionally defective spermatozoa in male farm animals and humans. Ubiquitin, a universal chaperone protein, marks other proteins for degradation by multi-subunit protease, the proteasome. We have discovered that ubiquitin binds selectively to the surface of defective bull spermatozoa during sperm maturation and passage through epididymis. Consequently, ubiquitinated defective spermatozoa can be detected in bull semen samples by various immunological and immunocytochemical techniques which provide an objective, quantifiable marker of bull sperm quality. Further, to the utility of ubiquitin as a 'negative' sperm/semen quality marker, increased bull sperm ubiquitin levels correlate negatively with bulls' fertility. Such a relationship was documented by comparing sperm ubiquitin levels with reproductive efficiency in artificial insemination as well as parentage from natural breeding in a two-sire pasture system. Ubiquitin-based sperm quality assays are relatively easy and not costly to perform and have a number of advantages over other methods of semen evaluation including objectivity, independence from semen handling and storage methods, and universality with regard to recognizing multiple types of obvious and cryptic sperm defects. Further effort will be focused on validation of such assays and their dissemination of artificial insemination and natural breeding programs.