title: Connexin43 is expressed in mouse fetal ovary.
abstract: Developmental studies have shown that connexin43 (Cx43) is expressed in the ovary from the first day of life and throughout the rest of postnatal development. In both mouse embryonic ovaries and testes, target-directed deletion of Cx43 gene induces a significant decrease in germinal cells, but the exact mechanism determining this reduction remains unknown. Moreover, recently we found that Cx43 is abundantly expressed in mouse testes from the earliest stages of its fetal development. In the present work we investigate whether Cx43 transcript and protein are expressed in mouse embryonic ovaries. Total RNA was analyzed with specific Cx43 oligonucleotides in RT-PCR studies. A Cx43 PCR product was detected in ovaries at 16.5 and 18.5 days postcoitum (dpc). Bands of 43-45 kDa, characteristic of Cx43, were detected in immunoblots of total homogenates of ovaries at 14.5 and 18.5 dpc. Cell type-specific expression of Cx43 was investigated using double-labeled sections incubated with specific antibodies against Cx43 and the enzyme 3beta-hydroxysteroid dehydrogenase (3betaHSD) or a germ cell nuclear antigen (GCNA1), which are cell markers of steroidogenic and germinal cells, respectively. At 18.5 dpc, Cx43 was found in conglomerates of 3betaHSD-positive cells. Cx43 was also localized at homocellular junctions between parenchyma pregranulosa cells, and at heterocellular junctions between pregranulosa and germinal cells. At these two latter localizations, Cx43 was traced back to 12.5 dpc. In conclusion, this study demonstrates for the first time that from the earliest stages of embryonic ovary development, Cx43 is expressed in principal cell types involved in control of female fertility. These data suggest that the gap junctions formed with Cx43 between somatic and germinal cells may be necessary for prenatal expansion of germinal cells at initial stages of fetal gonadal development.
authors.affiliation: Unidad de Salud Reproductiva, UNISSER, Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Hospital General de México, México DF, México. eperez@servidor.unam.mx
authors.forename: E Martha
authors.initials: EM
authors.lastname: Pérez-Armendariz
authors.forename: Juan C
authors.initials: JC
authors.lastname: Sáez
authors.forename: J Francisco
authors.initials: JF
authors.lastname: Bravo-Moreno
authors.forename: Victoria
authors.initials: V
authors.lastname: López-Olmos
authors.forename: George C
authors.initials: GC
authors.lastname: Enders
authors.forename: Irma
authors.initials: I
authors.lastname: Villalpando
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000818:Animals; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005333:Fetus / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007124:Immunoenzyme Techniques; D051379:Mice / Q000378:metabolism*; D010053:Ovary / Q000196:embryology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013799:Theca Cells / Q000378:metabolism
chemical_list: D018031:Connexin 43; D017931:DNA Primers; D012333:RNA, Messenger; D015096:3-Hydroxysteroid Dehydrogenases