Expression of Fas-Fas ligand system associated with atresia through apoptosis in murine ovary.
We examined the contribution of Fas and its ligand (FasL) in the process of follicular atresia using murine intraovarian follicles and pregnant mare's serum gonadotropin (PMSG)-hyperovulated eggs. Reverse transcriptase/polymerase chain reaction-Southern blot hybridization demonstrated positive expression of Fas in both intraovarian oocytes and hyperovulated eggs. In contrast, expression of FasL was only detected in granulosa cells. These findings were histologically confirmed by in situ hybridization using Fas- and FasL-specific probes. A time-course study showed that Fas mRNA was positive in atretic follicles through day 0 and day 2 of PMSG stimulation and negative thereafter. Levels of FasL mRNA were the highest on day 1 and tapered off toward day 5 of PMSG stimulation. Levels of elongation factor 1 alpha mRNA, a constitutive element, were constantly maintained throughout the experimental period. Coculture of ovulated eggs, intact and zona-free, and granulosa cells demonstrated positive TUNEL staining only in zona-free eggs. These findings indicate that follicular atresia is caused by apoptosis, and the apoptosis associated with internucleosomal DNA fragmentation is directly regulated by the Fas/FasL system.
Mori
T
T
Department of Immunology, University of Tokyo, Japan. ts-mori@hge.ims.u-tokyo.ac.jp
Xu
J P
JP
Mori
E
E
Sato
E
E
Saito
S
S
Guo
M W
MW
D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D015139:Blotting, Southern; D053938:DNA Fragmentation; D018076:DNA, Complementary / Q000302:isolation & purification; D053222:Fas Ligand Protein; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005496:Follicular Atresia / Q000276:immunology* / Q000378:metabolism; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006107:Granulosa Cells / Q000276:immunology* / Q000378:metabolism; D008024:Ligands; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008815:Mice, Inbred Strains; D009707:Nucleosomes / Q000737:chemistry; D006080:Ovarian Follicle / Q000276:immunology* / Q000378:metabolism; D010063:Ovum / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D019014:fas Receptor / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics
D000954:Antigens, Surface; D018076:DNA, Complementary; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D006064:Gonadotropins, Equine; D008024:Ligands; D008562:Membrane Glycoproteins; D009707:Nucleosomes; D012333:RNA, Messenger; D019014:fas Receptor