Expression of epithelial cadherin in the developing and adult pig ovary.
Epithelial cadherin (E-cadherin) is one member of a family of intracellular calcium (Ca(2+))-dependent adhesion molecules that mediates selective cell-cell adhesion in a variety of species. Since changes in adhesive function accompany ovarian tissue development and remodeling, we were interested in studying the expression of E-cadherin during ovarian maturation in the pig. The objectives of this study were 1) to investigate the pattern of E-cadherin mRNA and protein expression during ovarian ontogeny in the pig, 2) to identify specific cells expressing E-cadherin in the mature porcine ovary, and 3) to compare E-cadherin expression in cells of morphologically healthy and atretic follicles. The results showed the presence of a 120-kDa protein, corresponding to E-cadherin, which was highest in fetal and neonatal ovaries and declined markedly (3- to 8-fold, p < 0.05) with maturity (16 wk to adult). In the adult ovary, E-cadherin was highest in ovarian surface epithelium (OSE) whereas in healthy follicles, granulosa cells had the highest levels. A significant decline (p < 0.05) in E-cadherin expression was evident in granulosa and theca cells from atretic follicles when compared with E-cadherin expression in cells of healthy follicles. A 4.2-kb E-cadherin transcript was detected in ovaries from 15-day-old pigs, and expression was markedly reduced (p < 0.05) by 16 wk of age. In the ovary of pregnancy, there was a faint E-cadherin mRNA signal, whereas in follicles the signal was stronger and uniform across follicle size. This is the first report that E-cadherin is expressed by the porcine ovary during ontogeny and that follicular and OSE cells of the adult ovary express the protein. Although the role of E-cadherin in the porcine ovary is unknown, the decline in E-cadherin expression in atretic follicular cells suggests that E-cadherin has a role in maintaining the structural integrity of the ovarian follicle during growth and development.
Ryan
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PL
Department of Animal Sciences, Rutgers, State University of New Jersey, New Brunswick 08903, USA.
Valentine
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AF
Bagnell
C A
CA
D000375:Aging; D000818:Animals; D015152:Blotting, Northern; D015820:Cadherins / Q000235:genetics*; D004848:Epithelium / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006107:Granulosa Cells / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism; D010053:Ovary / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D013552:Swine; D013799:Theca Cells / Q000378:metabolism
D015820:Cadherins; D012333:RNA, Messenger