The major maturation glycoprotein found on rat cauda epididymal sperm surface is linked to the membrane via phosphatidylinositol

Male-specific Modification of Human CD52

“…Surface carbohydrate labeling experiments on intact rat spermatozoa from the cauda epididymidis (14 -16) show a very high selectivity: the only accessible molecule is the rat counterpart of CD52 (7,16,17). Since it appears on the sperm surface coinciding with the acquisition of fertilizing capacity, it was also called the "major maturation-associated antigen" (18,19). Thus, acquisition of the CD52 antigen seems to be one of the major events forming the glycocalyx of mammalian spermatozoa (7,10,17).…”

Synthesis and glycosylation of CD52, the major 'maturation-associated' antigen of rat spermatozoa, in the cauda epididymidis

“…cauda spermatozoa) were collected and treated with phosphatidylinositol-specific phospholipase C (PI-specific PLC; Sigma; Type III) as described by Moore et al (1989). Briefly, the number of spermatozoa was determined and the sample was divided into aliquots, each containing approximately 2 ϫ 10 7 to 1 ϫ 10 8 spermatozoa.…”

“…As an alternative mechanism, it has been suggested that modifications of carbohydrates of pre-existing sperm glycoproteins from the testis occur during epididymal transit, possibly catalysed by a variety of extracellular carbohydrate-modifying enzyme activities in the epididymal fluid and on the sperm surface (for a review, see Tulsiani et al, 1999). Rat CD52, previously named the 'major maturation-associated sperm membrane antigen' (Zeheb and Orr, 1984;Moore et al, 1989), an approximately 26 kDa protein (Myles, 1993), and sperm membrane glycoprotein (SmemG) (Eccleston et al, 1994) may be an example of such a glycoprotein. Rat CD52 was originally identified as the principal molecule labelled by surface carbohydrate-labelling experiments using intact mature spermatozoa from the cauda epididymidis (Olson and Hamilton, 1978;Jones et al, 1981;Brown et al, 1983;Zeheb and Orr, 1984;Hamilton et al, 1986;Olson et al, 1987;Moore et al, 1989;Eccleston et al, 1994).…”

“…Rat CD52, previously named the 'major maturation-associated sperm membrane antigen' (Zeheb and Orr, 1984;Moore et al, 1989), an approximately 26 kDa protein (Myles, 1993), and sperm membrane glycoprotein (SmemG) (Eccleston et al, 1994) may be an example of such a glycoprotein. Rat CD52 was originally identified as the principal molecule labelled by surface carbohydrate-labelling experiments using intact mature spermatozoa from the cauda epididymidis (Olson and Hamilton, 1978;Jones et al, 1981;Brown et al, 1983;Zeheb and Orr, 1984;Hamilton et al, 1986;Olson et al, 1987;Moore et al, 1989;Eccleston et al, 1994). Furthermore, carbohydrate labelling of rat sperm glycoproteins on western blots in vitro (Pera et al, 1997) showed an unexpectedly high selectivity: the only molecule accessible to the periodate oxidation reaction was the counterpart of CD52.…”

“…As a glycosylphosphatidyl-inositol (GPI)-anchored integral sperm membrane protein, it was initially assumed to be a preexisting component originating at spermatogenesis and that its carbohydrate moiety underwent extensive modification only at a later stage within the epididymal duct (Hamilton et al, 1986;Moore et al, 1989;Eccleston et al, 1994; for a review, see Myles, 1993). However, molecular cloning and in situ transcript hybridization proved that the CD52 mRNA is synthesized by the epididymal duct epithelium (Kirchhoff, 1994(Kirchhoff, , 1996.…”