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  • 1
    Electronic Resource
    Electronic Resource
    Guinea pig proacrosin is synthesized principally by round spermatids and contains O-linked as well as N-linked oligosaccharide side chains (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 172-179 
    Details
    ISSN: 1040-452X
    Keywords: Acrosin ; Spermatogenic cells ; Guinea pig testis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Proacrosin is the zymogen precursor of acrosin, a sperm protease believed to play an essential role in fertilization. In this study, we used primary cultures of guinea pig spermatogenic cells to examine the temporal appearance and mechanisms of synthesis and processing of proacrosin during acrosome development. Following [35S]methionine incorporation and immunoprecipitation, cultured spermatogenic cells were found to synthesize two forms of proacrosin (Mr 54,000 and 57,000). Proacrosin was synthesized mainly by round spermatids. By immunoblotting, proacrosin became very prominent in round spermatids and persisted throughout spermiogenesis. Pluse-chase experiments demonstrated that the Mr 54,000 form of proacrosin was converted to the Mr 57,000 form, presumably reflecting posttranslational processing of carbohydrate side chains. When spermatogenic cells were cultured in the presence of tunicamycin, the synthesized proacrosin had an Mr of 54,000. However, in vitro translation of mRNA extracted from guinea pig testis followed by immunoprecipitation indicated that the core polypeptide of procrosin has an Mr of 44,000. Guinea pig spermatogenic cells incorporated glucosamine and fucose into the oligosaccharides of proacrosin. Treatment of guinea pig testis proacrosin with N-glycosidase or O-glycosidase reduced the Mr by 3-7%. These results indicate that proacrosin is synthesized by postmeiotic cells and the enzyme contains N- and O-linked oligosaccharides.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290213
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  • 2
    Electronic Resource
    Electronic Resource
    Maturation of guinea pig sperm in the epididymis involves the modification of proacrosin oligosaccharide side chains (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 294-301 
    Details
    ISSN: 1040-452X
    Keywords: Sperm ; Testis ; Epididymis ; Acrosome ; Proacrosin ; Glycoprotein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Proacrosin from guinea pig cauda epididymal sperm has a lower molecular weight compared with the testicular zymogen. In this study, we have examined the structural basis of this change and where the conversion in proacrosin molecular weight occurs during sperm maturation. Immunoblotting of trifluoromethane-sulfonic acid-deglycosylated testicular and cauda epididymal sperm extracts with antibody to guinea pig testicular proacrosin demonstrated that the polypeptide backbones of proacrosins from the testis and cauda epididymal sperm had the same molecular weights (∽44,000). Keratanase, an endo-β-galactosidase specific for lactosaminoglycans, partially digested testicular proacrosin but had no effect on proacrosin from cauda epididymal sperm. In extracts of testis, caput epididymis, and corpus epididymis analyzed by immunoblotting, anti-proacrosin recognized a major antigen with an apparent molecular weight (Mr) of 55,000, although a 50,000-Mr minor antigen began to appear in the corpus epididymis. By contrast, extracts of cauda epididymis, vas deferens, and cauda epididymal sperm had the 50,000 Mr protein as the only immunoreactive antigen. By enzymography following electrophoresis, the major bands of proteolytic activity in extracts of testis, caput epididymis, and corpus epididymis had 55,000 Mr. A band of protease activity with 55,000 Mr also appeared in extracts of the corpus epididymis. However, the most prominent bands of proteolytic activity in cauda epididymis, vas deferens, and cauda epididymal sperm had 50,000 Mr. In addition, two other major protease activities were detected with 32,000 and 34,000 Mr; the relationships of these proteases to proacrosin are unclear. From these results, we conclude that the oligosaccharides of proacrosin are altered during epididymal transit and that this modification occurs in the corpus epididymis. Such structural alterations may be functionally significant, since sperm acquire the ability to fertilize eggs during epididymal maturation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290313
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    Paper (German National Licenses)
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