Meiotic arrest in human oocytes is maintained by a Gs signaling pathway.
In mammalian oocytes, the maintenance of meiotic prophase I arrest prior to the surge of LH that stimulates meiotic maturation depends on a high level of cAMP within the oocyte. In mouse and rat, the cAMP is generated in the oocyte, and this requires the activity of a constitutively active, Gs-linked receptor, GPR3 or GPR12, respectively. To examine if human oocyte meiotic arrest depends on a similar pathway, we used RT-PCR and Western blotting to look at whether human oocytes express the same components for maintaining arrest as rodent oocytes. RNA encoding GPR3, but not GPR12, was expressed. RNA encoding adenylate cyclase type 3, which is the major adenylate cyclase required for maintaining meiotic arrest in the mouse oocyte, was also expressed, as was Galphas protein. To determine if this pathway is functional in the human oocyte, we examined the effect of injecting a function-blocking antibody against Galphas on meiotic resumption. This antibody stimulated meiotic resumption of human oocytes that were maintained at the prophase I stage using a phosphodiesterase inhibitor. These results demonstrate that human oocytes maintain meiotic arrest prior to the LH surge using a signaling pathway similar to that of rodent oocytes.
DiLuigi
Andrea
A
Department of Cell Biology and Center for Advanced Reproductive Services, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
Weitzman
Vanessa N
VN
Pace
Margaret C
MC
Siano
Linda J
LJ
Maier
Donald
D
Mehlmann
Lisa M
LM
D000262:Adenylyl Cyclases / Q000235:genetics; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western; D005260:Female; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D049469:Meiotic Prophase I / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000737:chemistry / Q000166:cytology*; D012313:RNA / Q000032:analysis; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*
D000906:Antibodies; C097350:GPR12 protein, human; C092794:GPR3 protein, human; D043562:Receptors, G-Protein-Coupled; D012313:RNA; D007986:Luteinizing Hormone; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases