Increased expression of alphaq family G-proteins during oocyte maturation and early development of Xenopus laevis

G-proteins of the alphaq family link extracellular stimulation of plasma membrane receptors to phospholipase C and consequently to intracellular Ca2+ release. Because they might function in initiating Ca2+ release at fertilization, we examined Galphaq family proteins in oocytes and eggs of Xenopus l...

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Bibliographic Details
Published in:Developmental biology 1996-07, Vol.177 (1), p.300-308
Main Authors: Gallo, C J, Jones, T L, Aragay, A M, Jaffe, L A
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Brain Chemistry
Embryo, Nonmammalian - chemistry
Embryo, Nonmammalian - embryology
Gene Expression Regulation, Developmental - physiology
GTP-Binding Proteins - analysis
GTP-Binding Proteins - physiology
Immunoblotting
Molecular Sequence Data
Oligonucleotides, Antisense - pharmacology
Oocytes - chemistry
Oocytes - drug effects
Oogenesis - physiology
Signal Transduction - physiology
Xenopus - embryology
Xenopus - genetics
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Summary:G-proteins of the alphaq family link extracellular stimulation of plasma membrane receptors to phospholipase C and consequently to intracellular Ca2+ release. Because they might function in initiating Ca2+ release at fertilization, we examined Galphaq family proteins in oocytes and eggs of Xenopus laevis. Three members of this protein family were identified by immunoblotting and antisense depletion. These proteins are barely detectable in the immature oocyte, but undergo a 6-fold increase in amount during oocyte maturation. This increase in Galphaq family protein expression correlates with the acquisition, during oocyte maturation, of the ability to release Ca2+ at fertilization (Schlichter and Elinson, 1981, Dev. Biol. 83, 33-41). In contrast, amounts of Galphas and Galphai3 are constant during maturation. We also examined the amounts of Galphaq, Galphas, and Galphai3 proteins during early development. While amounts of Galphas and Galphai3 show little or no change, Galphaq family protein expression increases 27-fold between the egg and neurula stages, suggesting that these proteins may be important in initiating Ca2+ release during early development.
ISSN:0012-1606