- Title
- Repetitive sperm-induced Ca²⁺ transients in mouse oocytes are cell cycle dependent
- Creator
- Jones, Keith T.; Carroll, John; Merriman, Julie A.; Whittingham , David G.; Kono, Tomohiro
- Relation
- Development Vol. 121, Issue 10, p. 3259-3266
- Relation
- http://dev.biologists.org./content/121/10/3259.abstract
- Publisher
- The Company of Biologists
- Resource Type
- journal article
- Date
- 1995
- Description
- Mature mouse oocytes are arrested at metaphase of the second meiotic division. Completion of meiosis and a block to polyspermy is caused by a series of repetitive Ca²⁺ transients triggered by the sperm at fertilization. These Ca²⁺ transients have been widely reported to last for a number of hours but when, or why, they cease is not known. Here we show that Ca²⁺ transients cease during entry into interphase, at the time when pronuclei are forming. In fertilized oocytes arrested at metaphase using colcemid, Ca²⁺ transients continued for as long as measurements were made, up to 18 hours after fertilization. Therefore sperm is able to induce Ca²⁺ transients during metaphase but not during interphase. In addition metaphase II oocytes, but not pronuclear stage 1-cell embryos showed highly repetitive Ca²⁺ oscillations in response to microinjection of inositol trisphosphate. This was explored further by treating in vitro maturing oocytes at metaphase I for 4–5 hours with cycloheximide, which induced nuclear progression to interphase (nucleus formation) and subsequent re-entry to metaphase (nuclear envelope breakdown). Fertilization of cycloheximide-treated oocytes revealed that continuous Ca²⁺ oscillations in response to sperm were observed after nuclear envelope breakdown but not during interphase. However interphase oocytes were able to generate Ca²⁺ transients in response to thimerosal. This data suggests that the ability of the sperm to trigger repetitive Ca²⁺ transients in oocytes is modulated in a cell cycle-dependent manner.
- Subject
- cycloheximide; mitosis; meiosis; fertilization; mouse oocyte; Ca²⁺ transients
- Identifier
- uon:6546
- Identifier
- http://hdl.handle.net/1959.13/804185
- Identifier
- ISSN:0950-1991
- Language
- eng
- Full Text
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