(A, top) Three previously uncharacterized clones showing statistically significant high expression in TS6.5cells were used as probes for Northern blots. The probe for β-actin was used as a control. (Middle) DNA probe for H3138C09 showed E12.5 placenta-specific signal by Northern hybridization. The probe for β-actin was used as a control. (Bottom) Schematic representation of one novel TS-specific gene, TC527107, from the TIGR Gene Index (Quackenbush et al. 2001). The cDNA clone H3138C09 is localized to the 3′UTR of this gene. See text for details. (B, top) Total RNA was extracted from extraembryonic and embryonic parts at the different stages indicated and transferred onto nylon membranes, which were probed with either H3001A06 or β-actin and exposed for 8 d to a Phosphorscreen. (Middle) DIG-labeled RNA probe for H3001A06 was hybridized in situ to a section of E9.5 conceptus. (Bottom left) HE-staining shows three different layers of the placenta at E11.5. Bottom right: DIG-labeled RNA probe for H3001A06 was hybridized in situ to a section of E11.5 placenta. The signals were weak, but detectable in the spongiotrophoblast and labyrinthine trophoblast layers, but undetectable in surrounding decidua. (TG2) Secondary trophoblast giant cells; (De) decidua; (P1) placenta; (A1) allantois; (Ex) exocoelom; (vYS) visceral yolk sac; (Sp) spongiotrophoblast layer; (La) labyrinthine trophoblast layer.
