IDENTIFICATION BY SUBTRACTIVE HYBRIDIZATION OF A SPECTRUM OF NOVEL AND UNEXPECTED GENES ASSOCIATED WITH IN-VITRO DIFFERENTIATION OF HUMAN CYTOTROPHOBLAST CELLS

We have previously demonstrated that epidermal growth factor (EGF), co lony stimulating factor-1 (CSF-1), and granulocyte-monocyte colony sti mulating factor (GMCSF) stimulate, while transforming growth factor be ta 1 (TGF beta 1) inhibits, cytotrophoblast differentiation. To identi fy genes mediating EGF-induced differentiation, we constructed a subtr acted cDNA library between undifferentiated cytotrophoblast and differ entiating cytotrophoblast. We identified six novel genes and four know n syncytial products alpha-human chorionic gonadotrophin (alpha hCG) p regnancy-specific beta 1-glycoprotein, 3 beta-hydroxysteroid dehydroge nase, and plasminogen activator inhibitor type 1 whose mRNAs increased during differentiation. Ten other genes were identified whose mRNAs i ncreased during differentiation. Five of these (keratin 19, calcreticu lin, heat shock protein 27, serum and glucocorticoid-regulated kinase and adrenomedullin) were not previously reported to be expressed in pl acenta. Five other genes known to be expressed in placenta were identi fied: keratin 8, fibronectin, mitochondrial ATP synthase, H19, and cyt osolic copper-zinc superoxide dismutase (SOD-1). Several of these gene s may have regulatory functions in trophoblast differentiation. (C) 19 96 W. B. Saunders Company Ltd