Oocyte maturation in starfish is mediated by the beta gamma-subunit complex of a G-protein.
The stimulation of meiotic maturation of starfish oocytes by the hormone 1-methyladenine is mimicked by injection of beta gamma subunits of G-proteins from either retina or brain. Conversely, the hormone response is inhibited by injection of the GDP-bound forms of alpha i1 or alpha t subunits, or by injection of phosducin; all of these proteins should bind free beta gamma. alpha-subunit forms with reduced affinity for beta gamma (alpha i1 or alpha t bound to hydrolysis-resistant GTP analogs, or alpha i1-GMPPCP treated with trypsin to remove the amino terminus of the protein) are less effective inhibitors of 1-methyladenine action. These results indicate that the beta gamma subunit of a G-protein mediates 1-methyladenine stimulation of oocyte maturation.
Physiology Department, University of Connecticut Health Center, Farmington 06032.
L A
LA
Jaffe
C J
CJ
Gallo
R H
RH
Lee
Y K
YK
Ho
T L
TL
Jones
D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D005136:Eye Proteins / Q000494:pharmacology; D020555:GTP-Binding Protein Regulators; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D008540:Meiosis; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D009866:Oogenesis; D010750:Phosphoproteins / Q000494:pharmacology; D051381:Rats; D013215:Starfish; D015293:Transducin
D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D010750:Phosphoproteins; C065631:phosducin; C008407:1-methyladenine; D019204:GTP-Binding Proteins; D015293:Transducin; D000225:Adenine