Isolation, characterization, and localization of a sperm-bound N-acetylglucosaminidase that is indispensable for fertilization in the ascidian, Phallusia mammillata

Godknecht, Alexander J.; Honegger, Thomas G.

doi:10.1016/0012-1606(91)90090-p

Cited by 57 publications

(34 citation statements)

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“…Earlier findings from our laboratory (Godknecht & Honegger 1991;Honegger 1992) showed the existence of three ␤-hexosaminidase isoforms of 180, 165 and 148 kDa in mature P. mammillata eggs. In eggs from which the follicle and test cells had been removed, only the 180 kDa ␤-hexosaminidase was present.…”

Section: Discussionmentioning

confidence: 74%

“…In testis, expression of ␤-hexosaminidase mRNA was not detectable by in situ hybridization, although a high level of ␤-hexosaminidase activity was reported in mature sperm (Godknecht & Honegger 1991). There are three possible explanations: (i) a very low level of mRNA expression was present but not detectable; (ii) mRNA was expressed only at a later stage of spermatogenesis, which may take place not in the testis but in the spermiduct; or (although rather unlikely) (iii) sperm ␤-hexosaminidase has a completely different primary structure and cannot be detected by the egg enzyme-targeted probe.…”

Section: Discussionmentioning

confidence: 94%

“…They suggested that sperm binding could be mediated by an enzymesubstrate complex established between a sperm surface glycosidase and glycoside moieties on the egg coat. Because glycosidases usually have a low activity at neutral and alkaline conditions, a transitory stable lectin-like enzyme-substrate binding would be established in sea water (Hoshi 1984;Honegger 1986;Lambert 1989b;Godknecht & Honegger 1991;Godknecht & Honegger 1995). The currently favored model of ascidian fertilization claims that sperm ␤ -hexosaminidase participates in transient spermegg binding and that ␤ -hexosaminidase released from the egg contributes to the block against polyspermy (Lambert 1989a,b;Lambert et al .…”

Section: Introductionmentioning

confidence: 99%

“…Most models are based mainly on glycosidase assays and/or inhibition of enzyme activity in fertilization assays. Direct approaches to purify and/or characterize sperm (Godknecht & Honegger 1991;Downey & Lambert 1994) or egg (Lambert & Goode 1992;Matsuura et al . 1993;Matsuura et al .…”

Section: Introductionmentioning

confidence: 99%

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Molecular cloning and sequence analysis of an ascidian egg β‐N‐acetylhexosaminidase with a potential role in fertilization

Koyanagi

Honegger²

2003

Dev Growth Differ

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␤ -N-Acetylhexosaminidase, which is found almost ubiquitously in sperm of invertebrates and vertebrates, supposedly mediates a carbohydrate-based transient sperm-egg coat binding. In ascidians and mammals, ␤ -hexosaminidase released at fertilization from eggs has been proposed to modify sperm receptor glycoproteins of the egg envelope, thus setting up a block to polyspermy. Previously, it was shown that in potential sperm receptor glycoproteins of the ascidian Phallusia mammillata , N-acetylglucosamine is the prevailing glycoside residue and that the egg harbors three active molecular forms of ␤ -hexosaminidase. In the present study, P. mammillata ␤ -hexosaminidase cDNA was isolated from an ovarian cDNA library and characterized. The deduced amino acid sequence showed a high similarity with other known ␤ -hexosaminidases; however, P. mammillata ␤ -hexosaminidase had a unique potential N-glycosylation site. A phylogenetic analysis suggested that P. mammillata ␤ -hexosaminidase developed independently after having branched off from the common ancestor gene of the chordate enzyme before two isoforms of the mammalian enzyme appeared. In situ hybridization revealed stage-specific expression of ␤ -hexosaminidase mRNA during oogenesis in the oocyte and in the accessory test and follicle cells. This suggests that the three egg ␤ -hexosaminidase forms are specific for the oocyte, test cells and follicle cells.

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Section: Discussionmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular cloning and sequence analysis of an ascidian egg β‐N‐acetylhexosaminidase with a potential role in fertilization

Koyanagi

Honegger²

2003

Dev Growth Differ

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“…Several glycosidases are implicated in the process of recognition and binding in ascidian species, for example, ␣-L-fucosidase in self-sterile ascidians Ciona intestinalis (Hoshi et al 1983) and Halocynthia roretzi (Hoshi et al 1994), ␤-N-Acetylglucosaminidase in Phallusia mammillata (Godknecht & Honegger 1991;Honegger 1992). It is also suggested that sulfated, fucose-containing glycans of vitelline coat glycoproteins are responsible for the sperm binding to the vitelline coat in H. roretzi (Hirohashi 1995).…”

Section: Introductionmentioning

confidence: 99%

Sulfated O‐linked glycans of the vitelline coat as ligands in gamete interaction in the ascidian, Halocynthia roretzi

1999

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In the ascidian Halocynthia roretzi, sperm-egg binding is probably mediated through the interaction between ␣-L-fucosidase present on the sperm surface and anionic saccharide chains of the egg vitelline coat. To characterize biologically active glycans, total glycans were chemically released from the glycopeptide fraction of the vitelline coat. The fraction of uncharged glycans and two fractions of negatively charged glycans were separated by diethylaminoethyl-anion exchange chromatography. In a competitive inhibition assay of fertilization, both anionic fractions showed inhibitory activity, with more anionic glycans being most potent, while uncharged glycans were biologically inactive. Chemical desulfation combined with a competitive inhibition assay of fertilization and ion analysis determined that sulfate groups were responsible for anionic character and crucial for biological activity. Monosaccharide analysis of anionic fractions showed a high content of N-acetylgalactosamine, galactose, xylose and the presence of arabinose, mannose, N-acetylglucosamine, glucose and rhamnose. Glycans were O-linked and galactose and xylose residues were detected at reducing termini. Linkage analysis suggested that 1,4-linked xylose, 1,3-linked galactose and N-acetylgalactosamine residues, substituted to different degrees by sulfate groups on the C-3 and C-4 carbons, respectively, constituted the core structures of anionic glycans.

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Mercuric ions impair the fertilization potential, the resumption of meiosis, the formation of male pronucleus, and increase polyspermy, in the egg of the ascidianPhallusia mammillata

Franchet

Goudeau

1997

J. Exp. Zool.

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Isolation, characterization, and localization of a sperm-bound N-acetylglucosaminidase that is indispensable for fertilization in the ascidian, Phallusia mammillata

Cited by 57 publications

References 32 publications

Molecular cloning and sequence analysis of an ascidian egg β‐N‐acetylhexosaminidase with a potential role in fertilization

Molecular cloning and sequence analysis of an ascidian egg β‐N‐acetylhexosaminidase with a potential role in fertilization

Sulfated O‐linked glycans of the vitelline coat as ligands in gamete interaction in the ascidian, Halocynthia roretzi

Mercuric ions impair the fertilization potential, the resumption of meiosis, the formation of male pronucleus, and increase polyspermy, in the egg of the ascidianPhallusia mammillata

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