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  • Cell & Developmental Biology  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Acrogranin, an acrosomal cysteine-rich glycoprotein, is the precursor of the growth-modulating peptides, granulins, and epithelins, and is expressed in somatic as well as male germ cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 34 (1993), S. 233-243 
    Details
    ISSN: 1040-452X
    Keywords: Acrogranin ; Spermatogenesis ; Acrosomal marker ; Sperm ; Testis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Spermatogenesis is a unique system of differentiation involving cellular remodeling and the biogenesis of sperm-specific organelles. To study the biogenesis of one such organelle, the acrosome, we have been examining the gene expression, biosynthesis, and targeting of specific acrosomal proteins during mammalian spermatogenesis. An acrosomal marker that we recently purified and began characterizing is acrogranin, a 67,000-molecular-weight glycoprotein originally isolated from guinea pig testes. This glycoprotein is detected in pachytene spermatocytes and is found later in the acrosomes of developing spermatids and sperm. Immunoblotting of several tissues and immunofluorescent localization in frozen sections of guinea pig testes suggested that acrogranin was a germ cell-specific glycoprotein that was expressed meiotically and post-meiotically. However, Northern blot analysis demonstrated that the mRNA for acrogranin was ubiquitously expressed in all guinea pig and mouse tissues examined. Furthermore, the primary structures of guinea pig and mouse acrogranins, deduced from the cDNA sequences, reveal that this glycoprotein is a cysteine-rich molecule with a motif that is tandemly repeated seven times, very similar to that of the human epithelin/granulin precursor. We conclude that guinea pig and mouse acrogranins are homologues of the precursor of the human and rat epithelin/granulin peptides previously demonstrated to have growth-modulating properties. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080340302
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  • 2
    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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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    Radioiodination studies of the envelopes from Xenopus laevis eggs (1983)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 22 (1983), S. 235-244 
    Details
    ISSN: 0730-2312
    Keywords: fertilization ; egg envelopes ; glycoproteins ; molecular topography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: To investigate the molecular basis of the observed morphological and biological characteristics of coelomic egg envelopes (CE), vitelline envelopes (VE), and fertilization envelopes (FE) of Xenopus laevis eggs, envelopes were radioiodinated under a variety of conditions: in situ, isolated and intact, or solubilized. The distribution of 125I in envelope components was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Each envelope type displayed unique profiles when iodinated in the intact state. A major constituent of VE, the 41,500 molecular weight component, was not labeled in the intact state, although the corresponding component of CE was heavily labeled. After dissociation of the envelope by guanidine-HCl or sodium dodecyl sulfate, all of the components could be radioiodinated. However, when the envelopes (VE and FE) were dissolved by heating and subsequently radioiodinated by lactoperoxidase, the resulting radioactivity profile was similar to that of the intact envelopes, suggesting that in the heat-dissolved envelope, the individual components retain similar structural relations as in the intact envelope. Quantitative but not qualitative differences were found between the inner and outer aspects of VE and FE. The significance of these findings is discussed in relation to what is known about the morphological, biological, and molecular properties of the envelopes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240220405
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  • 5
    Electronic Resource
    Electronic Resource
    The coelomic envelope to vitelline envelope conversion in eggs of Xenopus laevis (1986)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 30 (1986), S. 341-350 
    Details
    ISSN: 0730-2312
    Keywords: egg ; vitelline envelope ; glycoprotein ; processing ; proteolysis ; sperm ; Xenopus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: An amphibian egg recovered from the body cavity is enclosed by a coelomic egg envelope. Upon transport down the oviduct, the envelope is converted to the vitelline envelope. The coelomic and vitelline envelopes are distinct in terms of sperm penetrability, ultrastructural morphology, and radioiodination profiles. In this study, the macromolecular compositions of these two envelopes were determined. Isolated envelopes were compared by one- and two-dimensional gel electrophoresis, peptide mapping, and radiolabeling. A protein with a molecular weight of 57,000 (57K) was present in the vitelline envelope but was absent in the coelomic envelope. A glycoprotein with a molecular weight of 43K in the coelomic envelope was converted to a component with a molecular weight of 4lK in the vitelline envelope. The 43K-molecular weight component of the coelomic envelopes could be radioiodinated by lactoperoxidase but no labeling of the 41K-molecular weight component occurred in the vitelline envelope. Peptide mapping using limited proteolysis established that the 43K-molecular weight component of the coelomic envelope was a precursor to the 41K-molecular weight component of the vitelline envelope. These molecular alterations may underlie the ultrastructural and physiological changes occurring in these envelopes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240300407
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