G protein gene expression during mouse oocyte growth and maturation, and preimplantation embryo development

Mol Reprod Dev. 1996 Jul;44(3):315-23. doi: 10.1002/(SICI)1098-2795(199607)44:3<315::AID-MRD5>3.0.CO;2-P.

Abstract

Fertilization in mammals initiates "egg activation," a series of events leading to embryo development. The signal transduction events that occur as a result of sperm-egg interactions and that initiate egg activation may be analogous to a ligand-receptor-effector pathway, but the details of this signaling pathway are poorly understood. Several lines of evidence support a role for guanine nucleotide-binding regulatory proteins (G proteins) in mammalian egg activation. Prior to initiating studies to examine further the role of specific G proteins in sperm-induced mouse egg activation, we needed to define the complement of G proteins expressed in the egg. Using a reverse transcription-polymerase chain reaction (RT-PCR) assay, the relative levels of mRNAs encoding specific G protein alpha, beta, and gamma subunits were determined in meiotically incompetent oocytes, fully-grown competent oocytes, metaphase II-arrested eggs, one-, two-, and eight-cell embryos, and blastocysts. mRNA transcripts representing all of the heterotrimeric G protein families were present at all of the stages examined, and all underwent significant changes in their patterns of expression. The following heterotrimeric G protein mRNA transcripts were present in oocytes, eggs, or preimplantation embryos: G alpha q family (q, 11, and 14), G alpha 12 family (12 and 13), G alpha i family (i1, i2, i3, t2, z, and s), beta subunits 1, 2, 4, and 5, and gamma subunits 2, 3, 5, and 7. A recently described large molecular weight G protein, G alpha h (Nakaoka et al., 1994: Science 264:1593-1596), was also present, G alpha 15, G alpha t1, G alpha olf, G alpha oA, G beta 3, G gamma 1, and G gamma 8 mRNA transcripts were not detected using this method. The most common pattern of expression observed was a maturation-associated decrease followed by an increase after the two-cell stage. Some transcripts, however, were expressed at low levels until the eight-cell to blastocyst stages, whereas others were expressed at high levels in the oocyte but following maturation declined and remained at a low level throughout preimplantation development.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • DNA, Complementary
  • Embryonic Development
  • Female
  • GTP-Binding Proteins / genetics*
  • Gene Expression*
  • Male
  • Mice
  • Molecular Sequence Data
  • Oocytes / metabolism
  • Pregnancy
  • RNA, Messenger

Substances

  • DNA, Complementary
  • RNA, Messenger
  • GTP-Binding Proteins

Associated data

  • GENBANK/L10666
  • GENBANK/L17074
  • GENBANK/U38494
  • GENBANK/U38495
  • GENBANK/U38496
  • GENBANK/U38497
  • GENBANK/U38498
  • GENBANK/U38499
  • GENBANK/U38500
  • GENBANK/U38501
  • GENBANK/U38502
  • GENBANK/U38503
  • GENBANK/U38505