FOG-2 and GATA-4 Are Coexpressed in the Mouse Ovary and Can Modulate Müllerian-Inhibiting Substance Expression

• Published in: Biology of reproduction 2003-04, Vol.68 (4), p.1333
• Main Authors: Mikko Anttonen, Ilkka Ketola, Helka Parviainen, Anna-Kaisa Pusa, Markku Heikinheimo
• Format: Article
• Language: English
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod.102.008599

Transcription factor GATA-4 has been suggested to have a role in mammalian gonadogenesis, e.g., through activation of the Müllerian-inhibiting substance ( MIS ) gene expression. Although the expression of GATA-4 during gonadogenesis has been elucidated in detail, very little is known about FOG-2, an essential cofactor for GATA-4, in ovarian development. We explored in detail the expression of FOG-2 and GATA-4 in the fetal and postnatal mouse ovary and in the fetal testis using Northern blotting, RNA in situ hybridization, and immunohistochemistry. GATA-4 and FOG-2 are evident in the bipotential urogenital ridge, and their expression persists in the fetal mouse ovary; this result is different from earlier reports of GATA-4 downregulation in the fetal ovary. In contrast to ovary, FOG-2 expression is lost in the fetal Sertoli cells along with the formation of the testicular cords, leading to the hypothesis that FOG-2 has a specific role in the fetal ovaries counteracting the transactivation of the MIS gene by GATA-4. In vitro transfection assays verified that FOG-2 is able to repress the effect of GATA-4 on MIS transactivation in granulosa cells. In postnatal ovary, granulosa cells of growing follicles express FOG-2, partially overlapping with the expression of MIS. These data suggest an important role for FOG-2 and the GATA transcription factors in the developing ovary.