Multiple forms of messenger ribonucleic acid encoding glycodelin in male genital tract

Abstract

Glycodelin-A is a human endometrium-derived glycoprotein with contraceptive and immunosuppressive activities. Recently, we found that seminal plasma contains immunoreactive glycodelin (GdS) that is differentially glycosylated and has no contraceptive activity. We now report localization and variant forms of GdS in the male genital tract. Northern blot and reverse transcription-PCR analyses showed that GdS mRNA is expressed in the seminal vesicles and ampulla of the vas deferens. Immunohistochemical staining localized GdS to the epithelial cells and lumen of glands in the seminal vesicles and ampullary part of the vas deferens. The same tissues and cells contained glycodelin mRNA as localized by in situ hybridization. Whereas the major reverse transcription-PCR products were identical to the glycodelin-A cDNA from decidual expression library, there were also several splicing variants of GdS mRNA. Seminal plasma also contained smaller immunoreactive forms of the GdS protein. Some of them were posttranslational cleavage products of GdS, because incubation of 125I-labeled GdS in seminal plasma resulted in smaller molecular weight cleavage products. Based on these results, we concluded that multiple forms of glycodelin mRNA are expressed in the male genital tract, including those lacking the coding sequences for the glycosylation sites, and that seminal plasma has proteolytic activity that cleaves GdS.