Injection of a boar sperm factor causes calcium oscillations in oocytes of the marsupial opossum, Monodelphis domestica.
At fertilisation, the sperm triggers an abrupt and transient increase in intracellular calcium ([Ca2+]i) in the oocyte cytoplasm. In eutherian mammals, oocytes exhibit multiple [Ca2+]i transients which are necessary for egg activation. We investigated [Ca2+]i in the marsupial opossum, Monodelphis domestica. Embryo development in this therian mammal is quite distinct from that in most Eutheria. Oestrus was induced in an adult female opossum by introduction of a male into her cage. Injection of a boar sperm extract induced repetitive increases in [Ca2+]i. Each oscillation travelled across and around the periphery of the egg in a wave-like manner. A control injection of KCl elicited no change in [Ca2+]i. This is the first observation of [Ca2+]i oscillations in the oocyte of a marsupial. The repetitive nature of the [Ca2+]i changes were more similar to those in oocytes of Eutheria than those in oocytes of non-mammalian vertebrates.
Witton
C J
CJ
Department of Molecular Biology & Biotechnology, University of Sheffield, UK.
Swann
K
K
Carroll
J
J
Moore
H D
HD
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002457:Cell Extracts / Q000737:chemistry; D005260:Female; D005306:Fertilization; D016257:Fura-2; D008297:Male; D008845:Microinjections; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000378:metabolism*; D009893:Opossums / Q000378:metabolism*; D013094:Spermatozoa / Q000737:chemistry*; D013552:Swine / Q000378:metabolism*
D002457:Cell Extracts; D002118:Calcium; D016257:Fura-2