Activation of Ciona Intestinalis at Fertilisation is Controlled by Nicotinamide Nucleotide Metabolism

Abstract

Fertilisation is characterised by an ion current across the oocyte plasma membrane (DeFelice et al., 1986), a transient increase in intracellular calcium (see Jaffe, 1985), and the release of the cell cycle block controlled at the level of MPF (Newport and Kirschner, 1984). The fertilisation calcium signal appears to trigger the resumption of the cell cycle at fertilisation in oocytes arrested at meiosis II or after the completion of meiosis (reviewed in Whitaker and Patel, 1990). However, the role of intracellular second messengers, including calcium, in the control of progression through the early meiotic cell cycle, is less well defined (see Whitaker and Patel, 1990; Whitaker, 1996).