- Title
- Different Ca²⁺-releasing abilities of sperm extracts compared with tissue extracts and phospholipase C isoforms in sea urchin egg homogenate and mouse eggs
- Creator
- Jones, Keith T.; Matsuda, Miho; Parrington, John; Katan, Matilda; Swann, Karl
- Relation
- Biochemical Journal Vol. 346, Issue 3, p. 743-749
- Publisher Link
- http://dx.doi.org/10.1042/0264-6021:3460743
- Publisher
- Portland Press
- Resource Type
- journal article
- Date
- 2000
- Description
- A soluble phospholipase C (PLC) from boar sperm generates InsP₃and hence causes Ca²⁺ release when added to sea urchin egg homogenate. This PLC activity is associated with the ability of sperm extracts to cause Ca²⁺ oscillations in mammalian eggs following fractionation. A sperm PLC may, therefore, be responsible for causing the observed Ca²⁺ oscillations at fertilization. In the present study we have further characterized this boar sperm PLC activity using sea urchin egg homogenate. Consistent with a sperm PLC acting on egg PtdIns(4,5)P₂, the ability of sperm extracts to release Ca²⁺ was blocked by preincubation with the PLC inhibitor U73122 or by the addition of neomycin to the homogenate. The Ca²⁺-releasing activity was also detectable in sperm from other species and in whole testis extracts. However, activity was not observed in extracts from other tissues. Moreover recombinant PLCβ1, -γ1, -γ2, -δ1, all of which had higher specific activities than boar sperm extracts, were not able to release Ca²⁺ in the sea urchin egg homogenate. In addition these PLCs were not able to cause Ca²⁺ oscillations following microinjection into mouse eggs. These results imply that the sperm PLC possesses distinct properties that allow it to hydrolyse PtdIns(4,5)P₂in eggs.
- Subject
- inositol 1,4,5-trisphosphate.; sperm; Ca²⁺; egg; fertilization; oscillations
- Identifier
- uon:6571
- Identifier
- http://hdl.handle.net/1959.13/804265
- Identifier
- ISSN:0264-6021
- Language
- eng
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