Xenopus laevis oocyte Gα subunits mRNAs Detection and quantitation during oogenesis and early embryogenesis by competitive reverse PCR

• Published in: FEBS letters 1992-11, Vol.313 (3), p.213-219
• Main Authors: Oñate, Alejandro, Herrera, Luisa, Antonelli, Marcelo, Birnbaumer, Lutz, Olate, Juan
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Biological and medical sciences; Embryology: invertebrates and vertebrates. Teratology; Fundamental and applied biological sciences. Psychology; G-protein; Gene Expression; GTP-Binding Proteins - genetics; Molecular embryology; Molecular Sequence Data; Oligodeoxyribonucleotides - chemistry; Oocyte; Oocytes - physiology; Oogenesis; PCR; Polymerase Chain Reaction; RNA, Messenger - genetics; Signal transduction; Xenopus laevis; Xenopus laevis - embryology; Xenopus laevis - genetics; α subunit
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(92)81194-Q

The expression of mRNAs coding for different Xenopus laevis oocyte Gα subunits was analyzed by the PCR technique. Using the nucleotide sequences of five previously cloned cDNAs for oocyte Gα subunits [FEBS Lett. 244, 188–192, 1989; FEBS Lett. 268, 27–31, 1990] and the highly sensitive reverse PCR reaction we found that Gαo, Gαi-1, Gαi-3 and Gαs species are present in oocyte stage VI, Gαo mRNA being the most abundant transcript. Gαo mRNA was further quantitated through oogenesis, unfertilized eggs and early embryogenesis stages by a competitive PCR reaction using an ‘in vitro’ deleted Gαo mRNA as the internal standard. Using this approach we found that Xenopus Gαo mRNA levels were constant during oogenesis and unfertilized eggs at a concentration of 3.5 pg of mRNA/stage (5 × 10 5 molecules) and diminish gradually during early embryogenesis, reaching a level of 0.3 pg in the gastrula stage. These findings show that oocyte Gαo, and perhaps the rest of the α subunits, are expressed as maternal mRNAs and could play an important role in signal transduction at the beginning of oocyte cell differentiation.